content: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.media;
  
  import android.annotation.IntDef;
  import android.annotation.IntRange;
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.annotation.RequiresPermission;
  import android.annotation.SdkConstant;
  import android.annotation.SdkConstant.SdkConstantType;
  import android.annotation.SuppressLint;
  import android.annotation.SystemApi;
  import android.annotation.SystemService;
  import android.annotation.TestApi;
  import android.annotation.UnsupportedAppUsage;
  import android.app.NotificationManager;
  import android.app.PendingIntent;
  import android.bluetooth.BluetoothCodecConfig;
  import android.bluetooth.BluetoothDevice;
  import android.bluetooth.BluetoothProfile;
  import android.content.ComponentName;
  import android.content.Context;
  import android.content.Intent;
  import android.media.audiopolicy.AudioPolicy;
  import android.media.audiopolicy.AudioPolicy.AudioPolicyFocusListener;
  import android.media.audiopolicy.AudioProductStrategy;
  import android.media.audiopolicy.AudioVolumeGroup;
  import android.media.audiopolicy.AudioVolumeGroupChangeHandler;
  import android.media.projection.MediaProjection;
  import android.media.session.MediaController;
  import android.media.session.MediaSession;
  import android.media.session.MediaSessionLegacyHelper;
  import android.media.session.MediaSessionManager;
  import android.net.Uri;
  import android.os.Binder;
  import android.os.Build;
  import android.os.Handler;
  import android.os.IBinder;
  import android.os.Looper;
  import android.os.Message;
  import android.os.Process;
  import android.os.RemoteException;
  import android.os.ServiceManager;
  import android.os.SystemClock;
  import android.os.UserHandle;
  import android.provider.Settings;
  import android.text.TextUtils;
  import android.util.ArrayMap;
  import android.util.Log;
  import android.util.Pair;
  import android.view.KeyEvent;
  
  import com.android.internal.annotations.GuardedBy;
  import com.android.internal.util.Preconditions;
  
  import java.io.IOException;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.Executor;
  
  
  /**
   * AudioManager provides access to volume and ringer mode control.
   */
  @SystemService(Context.AUDIO_SERVICE)
  public class AudioManager {
  
      private Context mOriginalContext;
      private Context mApplicationContext;
      private long mVolumeKeyUpTime;
      private final boolean mUseVolumeKeySounds;
      private final boolean mUseFixedVolume;
      private static final String TAG = "AudioManager";
      private static final boolean DEBUG = false;
      private static final AudioPortEventHandler sAudioPortEventHandler = new AudioPortEventHandler();
      private static final AudioVolumeGroupChangeHandler sAudioAudioVolumeGroupChangedHandler =
              new AudioVolumeGroupChangeHandler();
  
      /**
       * Broadcast intent, a hint for applications that audio is about to become
       * 'noisy' due to a change in audio outputs. For example, this intent may
       * be sent when a wired headset is unplugged, or when an A2DP audio
       * sink is disconnected, and the audio system is about to automatically
       * switch audio route to the speaker. Applications that are controlling
       * audio streams may consider pausing, reducing volume or some other action
       * on receipt of this intent so as not to surprise the user with audio
       * from the speaker.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_AUDIO_BECOMING_NOISY = "android.media.AUDIO_BECOMING_NOISY";
  
      /**
       * Sticky broadcast intent action indicating that the ringer mode has
       * changed. Includes the new ringer mode.
       *
       * @see #EXTRA_RINGER_MODE
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String RINGER_MODE_CHANGED_ACTION = "android.media.RINGER_MODE_CHANGED";
  
      /**
       * @hide
       * Sticky broadcast intent action indicating that the internal ringer mode has
       * changed. Includes the new ringer mode.
       *
       * @see #EXTRA_RINGER_MODE
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String INTERNAL_RINGER_MODE_CHANGED_ACTION =
              "android.media.INTERNAL_RINGER_MODE_CHANGED_ACTION";
  
      /**
       * The new ringer mode.
       *
       * @see #RINGER_MODE_CHANGED_ACTION
       * @see #RINGER_MODE_NORMAL
       * @see #RINGER_MODE_SILENT
       * @see #RINGER_MODE_VIBRATE
       */
      public static final String EXTRA_RINGER_MODE = "android.media.EXTRA_RINGER_MODE";
  
      /**
       * Broadcast intent action indicating that the vibrate setting has
       * changed. Includes the vibrate type and its new setting.
       *
       * @see #EXTRA_VIBRATE_TYPE
       * @see #EXTRA_VIBRATE_SETTING
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode and listen to {@link #RINGER_MODE_CHANGED_ACTION} instead.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String VIBRATE_SETTING_CHANGED_ACTION =
          "android.media.VIBRATE_SETTING_CHANGED";
  
      /**
       * @hide Broadcast intent when the volume for a particular stream type changes.
       * Includes the stream, the new volume and previous volumes.
       * Notes:
       *  - for internal platform use only, do not make public,
       *  - never used for "remote" volume changes
       *
       * @see #EXTRA_VOLUME_STREAM_TYPE
       * @see #EXTRA_VOLUME_STREAM_VALUE
       * @see #EXTRA_PREV_VOLUME_STREAM_VALUE
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      @UnsupportedAppUsage
      public static final String VOLUME_CHANGED_ACTION = "android.media.VOLUME_CHANGED_ACTION";
  
      /**
       * @hide Broadcast intent when the devices for a particular stream type changes.
       * Includes the stream, the new devices and previous devices.
       * Notes:
       *  - for internal platform use only, do not make public,
       *  - never used for "remote" volume changes
       *
       * @see #EXTRA_VOLUME_STREAM_TYPE
       * @see #EXTRA_VOLUME_STREAM_DEVICES
       * @see #EXTRA_PREV_VOLUME_STREAM_DEVICES
       * @see #getDevicesForStream
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String STREAM_DEVICES_CHANGED_ACTION =
          "android.media.STREAM_DEVICES_CHANGED_ACTION";
  
      /**
       * @hide Broadcast intent when a stream mute state changes.
       * Includes the stream that changed and the new mute state
       *
       * @see #EXTRA_VOLUME_STREAM_TYPE
       * @see #EXTRA_STREAM_VOLUME_MUTED
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String STREAM_MUTE_CHANGED_ACTION =
          "android.media.STREAM_MUTE_CHANGED_ACTION";
  
      /**
       * @hide Broadcast intent when the master mute state changes.
       * Includes the the new volume
       *
       * @see #EXTRA_MASTER_VOLUME_MUTED
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String MASTER_MUTE_CHANGED_ACTION =
          "android.media.MASTER_MUTE_CHANGED_ACTION";
  
      /**
       * The new vibrate setting for a particular type.
       *
       * @see #VIBRATE_SETTING_CHANGED_ACTION
       * @see #EXTRA_VIBRATE_TYPE
       * @see #VIBRATE_SETTING_ON
       * @see #VIBRATE_SETTING_OFF
       * @see #VIBRATE_SETTING_ONLY_SILENT
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode and listen to {@link #RINGER_MODE_CHANGED_ACTION} instead.
       */
      public static final String EXTRA_VIBRATE_SETTING = "android.media.EXTRA_VIBRATE_SETTING";
  
      /**
       * The vibrate type whose setting has changed.
       *
       * @see #VIBRATE_SETTING_CHANGED_ACTION
       * @see #VIBRATE_TYPE_NOTIFICATION
       * @see #VIBRATE_TYPE_RINGER
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode and listen to {@link #RINGER_MODE_CHANGED_ACTION} instead.
       */
      public static final String EXTRA_VIBRATE_TYPE = "android.media.EXTRA_VIBRATE_TYPE";
  
      /**
       * @hide The stream type for the volume changed intent.
       */
      @UnsupportedAppUsage
      public static final String EXTRA_VOLUME_STREAM_TYPE = "android.media.EXTRA_VOLUME_STREAM_TYPE";
  
      /**
       * @hide
       * The stream type alias for the volume changed intent.
       * For instance the intent may indicate a change of the {@link #STREAM_NOTIFICATION} stream
       * type (as indicated by the {@link #EXTRA_VOLUME_STREAM_TYPE} extra), but this is also
       * reflected by a change of the volume of its alias, {@link #STREAM_RING} on some devices,
       * {@link #STREAM_MUSIC} on others (e.g. a television).
       */
      public static final String EXTRA_VOLUME_STREAM_TYPE_ALIAS =
              "android.media.EXTRA_VOLUME_STREAM_TYPE_ALIAS";
  
      /**
       * @hide The volume associated with the stream for the volume changed intent.
       */
      @UnsupportedAppUsage
      public static final String EXTRA_VOLUME_STREAM_VALUE =
          "android.media.EXTRA_VOLUME_STREAM_VALUE";
  
      /**
       * @hide The previous volume associated with the stream for the volume changed intent.
       */
      public static final String EXTRA_PREV_VOLUME_STREAM_VALUE =
          "android.media.EXTRA_PREV_VOLUME_STREAM_VALUE";
  
      /**
       * @hide The devices associated with the stream for the stream devices changed intent.
       */
      public static final String EXTRA_VOLUME_STREAM_DEVICES =
          "android.media.EXTRA_VOLUME_STREAM_DEVICES";
  
      /**
       * @hide The previous devices associated with the stream for the stream devices changed intent.
       */
      public static final String EXTRA_PREV_VOLUME_STREAM_DEVICES =
          "android.media.EXTRA_PREV_VOLUME_STREAM_DEVICES";
  
      /**
       * @hide The new master volume mute state for the master mute changed intent.
       * Value is boolean
       */
      public static final String EXTRA_MASTER_VOLUME_MUTED =
          "android.media.EXTRA_MASTER_VOLUME_MUTED";
  
      /**
       * @hide The new stream volume mute state for the stream mute changed intent.
       * Value is boolean
       */
      public static final String EXTRA_STREAM_VOLUME_MUTED =
          "android.media.EXTRA_STREAM_VOLUME_MUTED";
  
      /**
       * Broadcast Action: Wired Headset plugged in or unplugged.
       *
       * You <em>cannot</em> receive this through components declared
       * in manifests, only by explicitly registering for it with
       * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)
       * Context.registerReceiver()}.
       *
       * <p>The intent will have the following extra values:
       * <ul>
       *   <li><em>state</em> - 0 for unplugged, 1 for plugged. </li>
       *   <li><em>name</em> - Headset type, human readable string </li>
       *   <li><em>microphone</em> - 1 if headset has a microphone, 0 otherwise </li>
       * </ul>
       * </ul>
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_HEADSET_PLUG =
              "android.intent.action.HEADSET_PLUG";
  
      /**
       * Broadcast Action: A sticky broadcast indicating an HDMI cable was plugged or unplugged.
       *
       * The intent will have the following extra values: {@link #EXTRA_AUDIO_PLUG_STATE},
       * {@link #EXTRA_MAX_CHANNEL_COUNT}, {@link #EXTRA_ENCODINGS}.
       * <p>It can only be received by explicitly registering for it with
       * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)}.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_HDMI_AUDIO_PLUG =
              "android.media.action.HDMI_AUDIO_PLUG";
  
      /**
       * Extra used in {@link #ACTION_HDMI_AUDIO_PLUG} to communicate whether HDMI is plugged in
       * or unplugged.
       * An integer value of 1 indicates a plugged-in state, 0 is unplugged.
       */
      public static final String EXTRA_AUDIO_PLUG_STATE = "android.media.extra.AUDIO_PLUG_STATE";
  
      /**
       * Extra used in {@link #ACTION_HDMI_AUDIO_PLUG} to define the maximum number of channels
       * supported by the HDMI device.
       * The corresponding integer value is only available when the device is plugged in (as expressed
       * by {@link #EXTRA_AUDIO_PLUG_STATE}).
       */
      public static final String EXTRA_MAX_CHANNEL_COUNT = "android.media.extra.MAX_CHANNEL_COUNT";
  
      /**
       * Extra used in {@link #ACTION_HDMI_AUDIO_PLUG} to define the audio encodings supported by
       * the connected HDMI device.
       * The corresponding array of encoding values is only available when the device is plugged in
       * (as expressed by {@link #EXTRA_AUDIO_PLUG_STATE}). Encoding values are defined in
       * {@link AudioFormat} (for instance see {@link AudioFormat#ENCODING_PCM_16BIT}). Use
       * {@link android.content.Intent#getIntArrayExtra(String)} to retrieve the encoding values.
       */
      public static final String EXTRA_ENCODINGS = "android.media.extra.ENCODINGS";
  
      /** Used to identify the volume of audio streams for phone calls */
      public static final int STREAM_VOICE_CALL = AudioSystem.STREAM_VOICE_CALL;
      /** Used to identify the volume of audio streams for system sounds */
      public static final int STREAM_SYSTEM = AudioSystem.STREAM_SYSTEM;
      /** Used to identify the volume of audio streams for the phone ring */
      public static final int STREAM_RING = AudioSystem.STREAM_RING;
      /** Used to identify the volume of audio streams for music playback */
      public static final int STREAM_MUSIC = AudioSystem.STREAM_MUSIC;
      /** Used to identify the volume of audio streams for alarms */
      public static final int STREAM_ALARM = AudioSystem.STREAM_ALARM;
      /** Used to identify the volume of audio streams for notifications */
      public static final int STREAM_NOTIFICATION = AudioSystem.STREAM_NOTIFICATION;
      /** @hide Used to identify the volume of audio streams for phone calls when connected
       *        to bluetooth */
      @UnsupportedAppUsage
      public static final int STREAM_BLUETOOTH_SCO = AudioSystem.STREAM_BLUETOOTH_SCO;
      /** @hide Used to identify the volume of audio streams for enforced system sounds
       *        in certain countries (e.g camera in Japan) */
      @UnsupportedAppUsage
      public static final int STREAM_SYSTEM_ENFORCED = AudioSystem.STREAM_SYSTEM_ENFORCED;
      /** Used to identify the volume of audio streams for DTMF Tones */
      public static final int STREAM_DTMF = AudioSystem.STREAM_DTMF;
      /** @hide Used to identify the volume of audio streams exclusively transmitted through the
       *        speaker (TTS) of the device */
      @UnsupportedAppUsage
      public static final int STREAM_TTS = AudioSystem.STREAM_TTS;
      /** Used to identify the volume of audio streams for accessibility prompts */
      public static final int STREAM_ACCESSIBILITY = AudioSystem.STREAM_ACCESSIBILITY;
  
      /** Number of audio streams */
      /**
       * @deprecated Do not iterate on volume stream type values.
       */
      @Deprecated public static final int NUM_STREAMS = AudioSystem.NUM_STREAMS;
  
      /**
       * Increase the ringer volume.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int ADJUST_RAISE = 1;
  
      /**
       * Decrease the ringer volume.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int ADJUST_LOWER = -1;
  
      /**
       * Maintain the previous ringer volume. This may be useful when needing to
       * show the volume toast without actually modifying the volume.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int ADJUST_SAME = 0;
  
      /**
       * Mute the volume. Has no effect if the stream is already muted.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int ADJUST_MUTE = -100;
  
      /**
       * Unmute the volume. Has no effect if the stream is not muted.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int ADJUST_UNMUTE = 100;
  
      /**
       * Toggle the mute state. If muted the stream will be unmuted. If not muted
       * the stream will be muted.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int ADJUST_TOGGLE_MUTE = 101;
  
      /** @hide */
      @IntDef(flag = false, prefix = "ADJUST", value = {
              ADJUST_RAISE,
              ADJUST_LOWER,
              ADJUST_SAME,
              ADJUST_MUTE,
              ADJUST_UNMUTE,
              ADJUST_TOGGLE_MUTE }
              )
      @Retention(RetentionPolicy.SOURCE)
      public @interface VolumeAdjustment {}
  
      /** @hide */
      public static final String adjustToString(int adj) {
          switch (adj) {
              case ADJUST_RAISE: return "ADJUST_RAISE";
              case ADJUST_LOWER: return "ADJUST_LOWER";
              case ADJUST_SAME: return "ADJUST_SAME";
              case ADJUST_MUTE: return "ADJUST_MUTE";
              case ADJUST_UNMUTE: return "ADJUST_UNMUTE";
              case ADJUST_TOGGLE_MUTE: return "ADJUST_TOGGLE_MUTE";
              default: return new StringBuilder("unknown adjust mode ").append(adj).toString();
          }
      }
  
      // Flags should be powers of 2!
  
      /**
       * Show a toast containing the current volume.
       *
       * @see #adjustStreamVolume(int, int, int)
       * @see #adjustVolume(int, int)
       * @see #setStreamVolume(int, int, int)
       * @see #setRingerMode(int)
       */
      public static final int FLAG_SHOW_UI = 1 << 0;
  
      /**
       * Whether to include ringer modes as possible options when changing volume.
       * For example, if true and volume level is 0 and the volume is adjusted
       * with {@link #ADJUST_LOWER}, then the ringer mode may switch the silent or
       * vibrate mode.
       * <p>
       * By default this is on for the ring stream. If this flag is included,
       * this behavior will be present regardless of the stream type being
       * affected by the ringer mode.
       *
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       */
      public static final int FLAG_ALLOW_RINGER_MODES = 1 << 1;
  
      /**
       * Whether to play a sound when changing the volume.
       * <p>
       * If this is given to {@link #adjustVolume(int, int)} or
       * {@link #adjustSuggestedStreamVolume(int, int, int)}, it may be ignored
       * in some cases (for example, the decided stream type is not
       * {@link AudioManager#STREAM_RING}, or the volume is being adjusted
       * downward).
       *
       * @see #adjustStreamVolume(int, int, int)
       * @see #adjustVolume(int, int)
       * @see #setStreamVolume(int, int, int)
       */
      public static final int FLAG_PLAY_SOUND = 1 << 2;
  
      /**
       * Removes any sounds/vibrate that may be in the queue, or are playing (related to
       * changing volume).
       */
      public static final int FLAG_REMOVE_SOUND_AND_VIBRATE = 1 << 3;
  
      /**
       * Whether to vibrate if going into the vibrate ringer mode.
       */
      public static final int FLAG_VIBRATE = 1 << 4;
  
      /**
       * Indicates to VolumePanel that the volume slider should be disabled as user
       * cannot change the stream volume
       * @hide
       */
      public static final int FLAG_FIXED_VOLUME = 1 << 5;
  
      /**
       * Indicates the volume set/adjust call is for Bluetooth absolute volume
       * @hide
       */
      public static final int FLAG_BLUETOOTH_ABS_VOLUME = 1 << 6;
  
      /**
       * Adjusting the volume was prevented due to silent mode, display a hint in the UI.
       * @hide
       */
      public static final int FLAG_SHOW_SILENT_HINT = 1 << 7;
  
      /**
       * Indicates the volume call is for Hdmi Cec system audio volume
       * @hide
       */
      public static final int FLAG_HDMI_SYSTEM_AUDIO_VOLUME = 1 << 8;
  
      /**
       * Indicates that this should only be handled if media is actively playing.
       * @hide
       */
      public static final int FLAG_ACTIVE_MEDIA_ONLY = 1 << 9;
  
      /**
       * Like FLAG_SHOW_UI, but only dialog warnings and confirmations, no sliders.
       * @hide
       */
      public static final int FLAG_SHOW_UI_WARNINGS = 1 << 10;
  
      /**
       * Adjusting the volume down from vibrated was prevented, display a hint in the UI.
       * @hide
       */
      public static final int FLAG_SHOW_VIBRATE_HINT = 1 << 11;
  
      /**
       * Adjusting the volume due to a hardware key press.
       * This flag can be used in the places in order to denote (or check) that a volume adjustment
       * request is from a hardware key press. (e.g. {@link MediaController}).
       * @hide
       */
      public static final int FLAG_FROM_KEY = 1 << 12;
  
      // The iterator of TreeMap#entrySet() returns the entries in ascending key order.
      private static final TreeMap<Integer, String> FLAG_NAMES = new TreeMap<>();
  
      static {
          FLAG_NAMES.put(FLAG_SHOW_UI, "FLAG_SHOW_UI");
          FLAG_NAMES.put(FLAG_ALLOW_RINGER_MODES, "FLAG_ALLOW_RINGER_MODES");
          FLAG_NAMES.put(FLAG_PLAY_SOUND, "FLAG_PLAY_SOUND");
          FLAG_NAMES.put(FLAG_REMOVE_SOUND_AND_VIBRATE, "FLAG_REMOVE_SOUND_AND_VIBRATE");
          FLAG_NAMES.put(FLAG_VIBRATE, "FLAG_VIBRATE");
          FLAG_NAMES.put(FLAG_FIXED_VOLUME, "FLAG_FIXED_VOLUME");
          FLAG_NAMES.put(FLAG_BLUETOOTH_ABS_VOLUME, "FLAG_BLUETOOTH_ABS_VOLUME");
          FLAG_NAMES.put(FLAG_SHOW_SILENT_HINT, "FLAG_SHOW_SILENT_HINT");
          FLAG_NAMES.put(FLAG_HDMI_SYSTEM_AUDIO_VOLUME, "FLAG_HDMI_SYSTEM_AUDIO_VOLUME");
          FLAG_NAMES.put(FLAG_ACTIVE_MEDIA_ONLY, "FLAG_ACTIVE_MEDIA_ONLY");
          FLAG_NAMES.put(FLAG_SHOW_UI_WARNINGS, "FLAG_SHOW_UI_WARNINGS");
          FLAG_NAMES.put(FLAG_SHOW_VIBRATE_HINT, "FLAG_SHOW_VIBRATE_HINT");
          FLAG_NAMES.put(FLAG_FROM_KEY, "FLAG_FROM_KEY");
      }
  
      /** @hide */
      public static String flagsToString(int flags) {
          final StringBuilder sb = new StringBuilder();
          for (Map.Entry<Integer, String> entry : FLAG_NAMES.entrySet()) {
              final int flag = entry.getKey();
              if ((flags & flag) != 0) {
                  if (sb.length() > 0) {
                      sb.append(',');
                  }
                  sb.append(entry.getValue());
                  flags &= ~flag;
              }
          }
          if (flags != 0) {
              if (sb.length() > 0) {
                  sb.append(',');
              }
              sb.append(flags);
          }
          return sb.toString();
      }
  
      /**
       * Ringer mode that will be silent and will not vibrate. (This overrides the
       * vibrate setting.)
       *
       * @see #setRingerMode(int)
       * @see #getRingerMode()
       */
      public static final int RINGER_MODE_SILENT = 0;
  
      /**
       * Ringer mode that will be silent and will vibrate. (This will cause the
       * phone ringer to always vibrate, but the notification vibrate to only
       * vibrate if set.)
       *
       * @see #setRingerMode(int)
       * @see #getRingerMode()
       */
      public static final int RINGER_MODE_VIBRATE = 1;
  
      /**
       * Ringer mode that may be audible and may vibrate. It will be audible if
       * the volume before changing out of this mode was audible. It will vibrate
       * if the vibrate setting is on.
       *
       * @see #setRingerMode(int)
       * @see #getRingerMode()
       */
      public static final int RINGER_MODE_NORMAL = 2;
  
      /**
       * Maximum valid ringer mode value. Values must start from 0 and be contiguous.
       * @hide
       */
      public static final int RINGER_MODE_MAX = RINGER_MODE_NORMAL;
  
      /**
       * Vibrate type that corresponds to the ringer.
       *
       * @see #setVibrateSetting(int, int)
       * @see #getVibrateSetting(int)
       * @see #shouldVibrate(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public static final int VIBRATE_TYPE_RINGER = 0;
  
      /**
       * Vibrate type that corresponds to notifications.
       *
       * @see #setVibrateSetting(int, int)
       * @see #getVibrateSetting(int)
       * @see #shouldVibrate(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public static final int VIBRATE_TYPE_NOTIFICATION = 1;
  
      /**
       * Vibrate setting that suggests to never vibrate.
       *
       * @see #setVibrateSetting(int, int)
       * @see #getVibrateSetting(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public static final int VIBRATE_SETTING_OFF = 0;
  
      /**
       * Vibrate setting that suggests to vibrate when possible.
       *
       * @see #setVibrateSetting(int, int)
       * @see #getVibrateSetting(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public static final int VIBRATE_SETTING_ON = 1;
  
      /**
       * Vibrate setting that suggests to only vibrate when in the vibrate ringer
       * mode.
       *
       * @see #setVibrateSetting(int, int)
       * @see #getVibrateSetting(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public static final int VIBRATE_SETTING_ONLY_SILENT = 2;
  
      /**
       * Suggests using the default stream type. This may not be used in all
       * places a stream type is needed.
       */
      public static final int USE_DEFAULT_STREAM_TYPE = Integer.MIN_VALUE;
  
      private static IAudioService sService;
  
      /**
       * @hide
       * For test purposes only, will throw NPE with some methods that require a Context.
       */
      @UnsupportedAppUsage
      public AudioManager() {
          mUseVolumeKeySounds = true;
          mUseFixedVolume = false;
      }
  
      /**
       * @hide
       */
      @UnsupportedAppUsage
      public AudioManager(Context context) {
          setContext(context);
          mUseVolumeKeySounds = getContext().getResources().getBoolean(
                  com.android.internal.R.bool.config_useVolumeKeySounds);
          mUseFixedVolume = getContext().getResources().getBoolean(
                  com.android.internal.R.bool.config_useFixedVolume);
      }
  
      private Context getContext() {
          if (mApplicationContext == null) {
              setContext(mOriginalContext);
          }
          if (mApplicationContext != null) {
              return mApplicationContext;
          }
          return mOriginalContext;
      }
  
      private void setContext(Context context) {
          mApplicationContext = context.getApplicationContext();
          if (mApplicationContext != null) {
              mOriginalContext = null;
          } else {
              mOriginalContext = context;
          }
      }
  
      @UnsupportedAppUsage
      private static IAudioService getService()
      {
          if (sService != null) {
              return sService;
          }
          IBinder b = ServiceManager.getService(Context.AUDIO_SERVICE);
          sService = IAudioService.Stub.asInterface(b);
          return sService;
      }
  
      /**
       * Sends a simulated key event for a media button.
       * To simulate a key press, you must first send a KeyEvent built with a
       * {@link KeyEvent#ACTION_DOWN} action, then another event with the {@link KeyEvent#ACTION_UP}
       * action.
       * <p>The key event will be sent to the current media key event consumer which registered with
       * {@link AudioManager#registerMediaButtonEventReceiver(PendingIntent)}.
       * @param keyEvent a {@link KeyEvent} instance whose key code is one of
       *     {@link KeyEvent#KEYCODE_MUTE},
       *     {@link KeyEvent#KEYCODE_HEADSETHOOK},
       *     {@link KeyEvent#KEYCODE_MEDIA_PLAY},
       *     {@link KeyEvent#KEYCODE_MEDIA_PAUSE},
       *     {@link KeyEvent#KEYCODE_MEDIA_PLAY_PAUSE},
       *     {@link KeyEvent#KEYCODE_MEDIA_STOP},
       *     {@link KeyEvent#KEYCODE_MEDIA_NEXT},
       *     {@link KeyEvent#KEYCODE_MEDIA_PREVIOUS},
       *     {@link KeyEvent#KEYCODE_MEDIA_REWIND},
       *     {@link KeyEvent#KEYCODE_MEDIA_RECORD},
       *     {@link KeyEvent#KEYCODE_MEDIA_FAST_FORWARD},
       *     {@link KeyEvent#KEYCODE_MEDIA_CLOSE},
       *     {@link KeyEvent#KEYCODE_MEDIA_EJECT},
       *     or {@link KeyEvent#KEYCODE_MEDIA_AUDIO_TRACK}.
       */
      public void dispatchMediaKeyEvent(KeyEvent keyEvent) {
          MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
          helper.sendMediaButtonEvent(keyEvent, false);
      }
  
      /**
       * @hide
       */
      public void preDispatchKeyEvent(KeyEvent event, int stream) {
          /*
           * If the user hits another key within the play sound delay, then
           * cancel the sound
           */
          int keyCode = event.getKeyCode();
          if (keyCode != KeyEvent.KEYCODE_VOLUME_DOWN && keyCode != KeyEvent.KEYCODE_VOLUME_UP
                  && keyCode != KeyEvent.KEYCODE_VOLUME_MUTE
                  && mVolumeKeyUpTime + AudioSystem.PLAY_SOUND_DELAY > SystemClock.uptimeMillis()) {
              /*
               * The user has hit another key during the delay (e.g., 300ms)
               * since the last volume key up, so cancel any sounds.
               */
              adjustSuggestedStreamVolume(ADJUST_SAME,
                      stream, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
          }
      }
  
      /**
       * Indicates if the device implements a fixed volume policy.
       * <p>Some devices may not have volume control and may operate at a fixed volume,
       * and may not enable muting or changing the volume of audio streams.
       * This method will return true on such devices.
       * <p>The following APIs have no effect when volume is fixed:
       * <ul>
       *   <li> {@link #adjustVolume(int, int)}
       *   <li> {@link #adjustSuggestedStreamVolume(int, int, int)}
       *   <li> {@link #adjustStreamVolume(int, int, int)}
       *   <li> {@link #setStreamVolume(int, int, int)}
       *   <li> {@link #setRingerMode(int)}
       *   <li> {@link #setStreamSolo(int, boolean)}
       *   <li> {@link #setStreamMute(int, boolean)}
       * </ul>
       */
      public boolean isVolumeFixed() {
          return mUseFixedVolume;
      }
  
      /**
       * Adjusts the volume of a particular stream by one step in a direction.
       * <p>
       * This method should only be used by applications that replace the platform-wide
       * management of audio settings or the main telephony application.
       * <p>This method has no effect if the device implements a fixed volume policy
       * as indicated by {@link #isVolumeFixed()}.
       * <p>From N onward, ringer mode adjustments that would toggle Do Not Disturb are not allowed
       * unless the app has been granted Do Not Disturb Access.
       * See {@link NotificationManager#isNotificationPolicyAccessGranted()}.
       *
       * @param streamType The stream type to adjust. One of {@link #STREAM_VOICE_CALL},
       * {@link #STREAM_SYSTEM}, {@link #STREAM_RING}, {@link #STREAM_MUSIC},
       * {@link #STREAM_ALARM} or {@link #STREAM_ACCESSIBILITY}.
       * @param direction The direction to adjust the volume. One of
       *            {@link #ADJUST_LOWER}, {@link #ADJUST_RAISE}, or
       *            {@link #ADJUST_SAME}.
       * @param flags One or more flags.
       * @see #adjustVolume(int, int)
       * @see #setStreamVolume(int, int, int)
       * @throws SecurityException if the adjustment triggers a Do Not Disturb change
       *   and the caller is not granted notification policy access.
       */
      public void adjustStreamVolume(int streamType, int direction, int flags) {
          final IAudioService service = getService();
          try {
              service.adjustStreamVolume(streamType, direction, flags,
                      getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Adjusts the volume of the most relevant stream. For example, if a call is
       * active, it will have the highest priority regardless of if the in-call
       * screen is showing. Another example, if music is playing in the background
       * and a call is not active, the music stream will be adjusted.
       * <p>
       * This method should only be used by applications that replace the
       * platform-wide management of audio settings or the main telephony
       * application.
       * <p>
       * This method has no effect if the device implements a fixed volume policy
       * as indicated by {@link #isVolumeFixed()}.
       *
       * @param direction The direction to adjust the volume. One of
       *            {@link #ADJUST_LOWER}, {@link #ADJUST_RAISE},
       *            {@link #ADJUST_SAME}, {@link #ADJUST_MUTE},
       *            {@link #ADJUST_UNMUTE}, or {@link #ADJUST_TOGGLE_MUTE}.
       * @param flags One or more flags.
       * @see #adjustSuggestedStreamVolume(int, int, int)
       * @see #adjustStreamVolume(int, int, int)
       * @see #setStreamVolume(int, int, int)
       * @see #isVolumeFixed()
       */
      public void adjustVolume(int direction, int flags) {
          MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
          helper.sendAdjustVolumeBy(USE_DEFAULT_STREAM_TYPE, direction, flags);
      }
  
      /**
       * Adjusts the volume of the most relevant stream, or the given fallback
       * stream.
       * <p>
       * This method should only be used by applications that replace the
       * platform-wide management of audio settings or the main telephony
       * application.
       * <p>
       * This method has no effect if the device implements a fixed volume policy
       * as indicated by {@link #isVolumeFixed()}.
       *
       * @param direction The direction to adjust the volume. One of
       *            {@link #ADJUST_LOWER}, {@link #ADJUST_RAISE},
       *            {@link #ADJUST_SAME}, {@link #ADJUST_MUTE},
       *            {@link #ADJUST_UNMUTE}, or {@link #ADJUST_TOGGLE_MUTE}.
       * @param suggestedStreamType The stream type that will be used if there
       *            isn't a relevant stream. {@link #USE_DEFAULT_STREAM_TYPE} is
       *            valid here.
       * @param flags One or more flags.
       * @see #adjustVolume(int, int)
       * @see #adjustStreamVolume(int, int, int)
       * @see #setStreamVolume(int, int, int)
       * @see #isVolumeFixed()
       */
      public void adjustSuggestedStreamVolume(int direction, int suggestedStreamType, int flags) {
          MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
          helper.sendAdjustVolumeBy(suggestedStreamType, direction, flags);
      }
  
      /** @hide */
      @UnsupportedAppUsage
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public void setMasterMute(boolean mute, int flags) {
          final IAudioService service = getService();
          try {
              service.setMasterMute(mute, flags, getContext().getOpPackageName(),
                      UserHandle.getCallingUserId());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the current ringtone mode.
       *
       * @return The current ringtone mode, one of {@link #RINGER_MODE_NORMAL},
       *         {@link #RINGER_MODE_SILENT}, or {@link #RINGER_MODE_VIBRATE}.
       * @see #setRingerMode(int)
       */
      public int getRingerMode() {
          final IAudioService service = getService();
          try {
              return service.getRingerModeExternal();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Checks valid ringer mode values.
       *
       * @return true if the ringer mode indicated is valid, false otherwise.
       *
       * @see #setRingerMode(int)
       * @hide
       */
      @UnsupportedAppUsage
      public static boolean isValidRingerMode(int ringerMode) {
          if (ringerMode < 0 || ringerMode > RINGER_MODE_MAX) {
              return false;
          }
          final IAudioService service = getService();
          try {
              return service.isValidRingerMode(ringerMode);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the maximum volume index for a particular stream.
       *
       * @param streamType The stream type whose maximum volume index is returned.
       * @return The maximum valid volume index for the stream.
       * @see #getStreamVolume(int)
       */
      public int getStreamMaxVolume(int streamType) {
          final IAudioService service = getService();
          try {
              return service.getStreamMaxVolume(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the minimum volume index for a particular stream.
       * @param streamType The stream type whose minimum volume index is returned. Must be one of
       *     {@link #STREAM_VOICE_CALL}, {@link #STREAM_SYSTEM},
       *     {@link #STREAM_RING}, {@link #STREAM_MUSIC}, {@link #STREAM_ALARM},
       *     {@link #STREAM_NOTIFICATION}, {@link #STREAM_DTMF} or {@link #STREAM_ACCESSIBILITY}.
       * @return The minimum valid volume index for the stream.
       * @see #getStreamVolume(int)
       */
      public int getStreamMinVolume(int streamType) {
          if (!isPublicStreamType(streamType)) {
              throw new IllegalArgumentException("Invalid stream type " + streamType);
          }
          return getStreamMinVolumeInt(streamType);
      }
  
      /**
       * @hide
       * Same as {@link #getStreamMinVolume(int)} but without the check on the public stream type.
       * @param streamType The stream type whose minimum volume index is returned.
       * @return The minimum valid volume index for the stream.
       * @see #getStreamVolume(int)
       */
      public int getStreamMinVolumeInt(int streamType) {
          final IAudioService service = getService();
          try {
              return service.getStreamMinVolume(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the current volume index for a particular stream.
       *
       * @param streamType The stream type whose volume index is returned.
       * @return The current volume index for the stream.
       * @see #getStreamMaxVolume(int)
       * @see #setStreamVolume(int, int, int)
       */
      public int getStreamVolume(int streamType) {
          final IAudioService service = getService();
          try {
              return service.getStreamVolume(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      // keep in sync with frameworks/av/services/audiopolicy/common/include/Volume.h
      private static final float VOLUME_MIN_DB = -758.0f;
  
      /** @hide */
      @IntDef(flag = false, prefix = "STREAM", value = {
              STREAM_VOICE_CALL,
              STREAM_SYSTEM,
              STREAM_RING,
              STREAM_MUSIC,
              STREAM_ALARM,
              STREAM_NOTIFICATION,
              STREAM_DTMF,
              STREAM_ACCESSIBILITY }
      )
      @Retention(RetentionPolicy.SOURCE)
      public @interface PublicStreamTypes {}
  
      /**
       * Returns the volume in dB (decibel) for the given stream type at the given volume index, on
       * the given type of audio output device.
       * @param streamType stream type for which the volume is queried.
       * @param index the volume index for which the volume is queried. The index value must be
       *     between the minimum and maximum index values for the given stream type (see
       *     {@link #getStreamMinVolume(int)} and {@link #getStreamMaxVolume(int)}).
       * @param deviceType the type of audio output device for which volume is queried.
       * @return a volume expressed in dB.
       *     A negative value indicates the audio signal is attenuated. A typical maximum value
       *     at the maximum volume index is 0 dB (no attenuation nor amplification). Muting is
       *     reflected by a value of {@link Float#NEGATIVE_INFINITY}.
       */
      public float getStreamVolumeDb(@PublicStreamTypes int streamType, int index,
              @AudioDeviceInfo.AudioDeviceTypeOut int deviceType) {
          if (!isPublicStreamType(streamType)) {
              throw new IllegalArgumentException("Invalid stream type " + streamType);
          }
          if (index > getStreamMaxVolume(streamType) || index < getStreamMinVolume(streamType)) {
              throw new IllegalArgumentException("Invalid stream volume index " + index);
          }
          if (!AudioDeviceInfo.isValidAudioDeviceTypeOut(deviceType)) {
              throw new IllegalArgumentException("Invalid audio output device type " + deviceType);
          }
          final float gain = AudioSystem.getStreamVolumeDB(streamType, index,
                  AudioDeviceInfo.convertDeviceTypeToInternalDevice(deviceType));
          if (gain <= VOLUME_MIN_DB) {
              return Float.NEGATIVE_INFINITY;
          } else {
              return gain;
          }
      }
  
      private static boolean isPublicStreamType(int streamType) {
          switch (streamType) {
              case STREAM_VOICE_CALL:
              case STREAM_SYSTEM:
              case STREAM_RING:
              case STREAM_MUSIC:
              case STREAM_ALARM:
              case STREAM_NOTIFICATION:
              case STREAM_DTMF:
              case STREAM_ACCESSIBILITY:
                  return true;
              default:
                  return false;
          }
      }
  
      /**
       * Get last audible volume before stream was muted.
       *
       * @hide
       */
      @UnsupportedAppUsage
      public int getLastAudibleStreamVolume(int streamType) {
          final IAudioService service = getService();
          try {
              return service.getLastAudibleStreamVolume(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Get the stream type whose volume is driving the UI sounds volume.
       * UI sounds are screen lock/unlock, camera shutter, key clicks...
       * It is assumed that this stream type is also tied to ringer mode changes.
       * @hide
       */
      public int getUiSoundsStreamType() {
          final IAudioService service = getService();
          try {
              return service.getUiSoundsStreamType();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Sets the ringer mode.
       * <p>
       * Silent mode will mute the volume and will not vibrate. Vibrate mode will
       * mute the volume and vibrate. Normal mode will be audible and may vibrate
       * according to user settings.
       * <p>This method has no effect if the device implements a fixed volume policy
       * as indicated by {@link #isVolumeFixed()}.
       * * <p>From N onward, ringer mode adjustments that would toggle Do Not Disturb are not allowed
       * unless the app has been granted Do Not Disturb Access.
       * See {@link NotificationManager#isNotificationPolicyAccessGranted()}.
       * @param ringerMode The ringer mode, one of {@link #RINGER_MODE_NORMAL},
       *            {@link #RINGER_MODE_SILENT}, or {@link #RINGER_MODE_VIBRATE}.
       * @see #getRingerMode()
       * @see #isVolumeFixed()
       */
      public void setRingerMode(int ringerMode) {
          if (!isValidRingerMode(ringerMode)) {
              return;
          }
          final IAudioService service = getService();
          try {
              service.setRingerModeExternal(ringerMode, getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Sets the volume index for a particular stream.
       * <p>This method has no effect if the device implements a fixed volume policy
       * as indicated by {@link #isVolumeFixed()}.
       * <p>From N onward, volume adjustments that would toggle Do Not Disturb are not allowed unless
       * the app has been granted Do Not Disturb Access.
       * See {@link NotificationManager#isNotificationPolicyAccessGranted()}.
       * @param streamType The stream whose volume index should be set.
       * @param index The volume index to set. See
       *            {@link #getStreamMaxVolume(int)} for the largest valid value.
       * @param flags One or more flags.
       * @see #getStreamMaxVolume(int)
       * @see #getStreamVolume(int)
       * @see #isVolumeFixed()
       * @throws SecurityException if the volume change triggers a Do Not Disturb change
       *   and the caller is not granted notification policy access.
       */
      public void setStreamVolume(int streamType, int index, int flags) {
          final IAudioService service = getService();
          try {
              service.setStreamVolume(streamType, index, flags, getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Sets the volume index for a particular {@link AudioAttributes}.
       * @param attr The {@link AudioAttributes} whose volume index should be set.
       * @param index The volume index to set. See
       *          {@link #getMaxVolumeIndexForAttributes(AudioAttributes)} for the largest valid value
       *          {@link #getMinVolumeIndexForAttributes(AudioAttributes)} for the lowest valid value.
       * @param flags One or more flags.
       * @see #getMaxVolumeIndexForAttributes(AudioAttributes)
       * @see #getMinVolumeIndexForAttributes(AudioAttributes)
       * @see #isVolumeFixed()
       * @hide
       */
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public void setVolumeIndexForAttributes(@NonNull AudioAttributes attr, int index, int flags) {
          Preconditions.checkNotNull(attr, "attr must not be null");
          final IAudioService service = getService();
          try {
              service.setVolumeIndexForAttributes(attr, index, flags,
                                                  getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the current volume index for a particular {@link AudioAttributes}.
       *
       * @param attr The {@link AudioAttributes} whose volume index is returned.
       * @return The current volume index for the stream.
       * @see #getMaxVolumeIndexForAttributes(AudioAttributes)
       * @see #getMinVolumeIndexForAttributes(AudioAttributes)
       * @see #setVolumeForAttributes(AudioAttributes, int, int)
       * @hide
       */
      @SystemApi
      @IntRange(from = 0)
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public int getVolumeIndexForAttributes(@NonNull AudioAttributes attr) {
          Preconditions.checkNotNull(attr, "attr must not be null");
          final IAudioService service = getService();
          try {
              return service.getVolumeIndexForAttributes(attr);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the maximum volume index for a particular {@link AudioAttributes}.
       *
       * @param attr The {@link AudioAttributes} whose maximum volume index is returned.
       * @return The maximum valid volume index for the {@link AudioAttributes}.
       * @see #getVolumeIndexForAttributes(AudioAttributes)
       * @hide
       */
      @SystemApi
      @IntRange(from = 0)
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public int getMaxVolumeIndexForAttributes(@NonNull AudioAttributes attr) {
          Preconditions.checkNotNull(attr, "attr must not be null");
          final IAudioService service = getService();
          try {
              return service.getMaxVolumeIndexForAttributes(attr);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the minimum volume index for a particular {@link AudioAttributes}.
       *
       * @param attr The {@link AudioAttributes} whose minimum volume index is returned.
       * @return The minimum valid volume index for the {@link AudioAttributes}.
       * @see #getVolumeIndexForAttributes(AudioAttributes)
       * @hide
       */
      @SystemApi
      @IntRange(from = 0)
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public int getMinVolumeIndexForAttributes(@NonNull AudioAttributes attr) {
          Preconditions.checkNotNull(attr, "attr must not be null");
          final IAudioService service = getService();
          try {
              return service.getMinVolumeIndexForAttributes(attr);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Solo or unsolo a particular stream.
       * <p>
       * Do not use. This method has been deprecated and is now a no-op.
       * {@link #requestAudioFocus} should be used for exclusive audio playback.
       *
       * @param streamType The stream to be soloed/unsoloed.
       * @param state The required solo state: true for solo ON, false for solo
       *            OFF
       * @see #isVolumeFixed()
       * @deprecated Do not use. If you need exclusive audio playback use
       *             {@link #requestAudioFocus}.
       */
      @Deprecated
      public void setStreamSolo(int streamType, boolean state) {
          Log.w(TAG, "setStreamSolo has been deprecated. Do not use.");
      }
  
      /**
       * Mute or unmute an audio stream.
       * <p>
       * This method should only be used by applications that replace the
       * platform-wide management of audio settings or the main telephony
       * application.
       * <p>
       * This method has no effect if the device implements a fixed volume policy
       * as indicated by {@link #isVolumeFixed()}.
       * <p>
       * This method was deprecated in API level 22. Prior to API level 22 this
       * method had significantly different behavior and should be used carefully.
       * The following applies only to pre-22 platforms:
       * <ul>
       * <li>The mute command is protected against client process death: if a
       * process with an active mute request on a stream dies, this stream will be
       * unmuted automatically.</li>
       * <li>The mute requests for a given stream are cumulative: the AudioManager
       * can receive several mute requests from one or more clients and the stream
       * will be unmuted only when the same number of unmute requests are
       * received.</li>
       * <li>For a better user experience, applications MUST unmute a muted stream
       * in onPause() and mute is again in onResume() if appropriate.</li>
       * </ul>
       *
       * @param streamType The stream to be muted/unmuted.
       * @param state The required mute state: true for mute ON, false for mute
       *            OFF
       * @see #isVolumeFixed()
       * @deprecated Use {@link #adjustStreamVolume(int, int, int)} with
       *             {@link #ADJUST_MUTE} or {@link #ADJUST_UNMUTE} instead.
       */
      @Deprecated
      public void setStreamMute(int streamType, boolean state) {
          Log.w(TAG, "setStreamMute is deprecated. adjustStreamVolume should be used instead.");
          int direction = state ? ADJUST_MUTE : ADJUST_UNMUTE;
          if (streamType == AudioManager.USE_DEFAULT_STREAM_TYPE) {
              adjustSuggestedStreamVolume(direction, streamType, 0);
          } else {
              adjustStreamVolume(streamType, direction, 0);
          }
      }
  
      /**
       * Returns the current mute state for a particular stream.
       *
       * @param streamType The stream to get mute state for.
       * @return The mute state for the given stream.
       * @see #adjustStreamVolume(int, int, int)
       */
      public boolean isStreamMute(int streamType) {
          final IAudioService service = getService();
          try {
              return service.isStreamMute(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * get master mute state.
       *
       * @hide
       */
      @UnsupportedAppUsage
      public boolean isMasterMute() {
          final IAudioService service = getService();
          try {
              return service.isMasterMute();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * forces the stream controlled by hard volume keys
       * specifying streamType == -1 releases control to the
       * logic.
       *
       * @hide
       */
      @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
      @UnsupportedAppUsage
      public void forceVolumeControlStream(int streamType) {
          final IAudioService service = getService();
          try {
              service.forceVolumeControlStream(streamType, mICallBack);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns whether a particular type should vibrate according to user
       * settings and the current ringer mode.
       * <p>
       * This shouldn't be needed by most clients that use notifications to
       * vibrate. The notification manager will not vibrate if the policy doesn't
       * allow it, so the client should always set a vibrate pattern and let the
       * notification manager control whether or not to actually vibrate.
       *
       * @param vibrateType The type of vibrate. One of
       *            {@link #VIBRATE_TYPE_NOTIFICATION} or
       *            {@link #VIBRATE_TYPE_RINGER}.
       * @return Whether the type should vibrate at the instant this method is
       *         called.
       * @see #setVibrateSetting(int, int)
       * @see #getVibrateSetting(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public boolean shouldVibrate(int vibrateType) {
          final IAudioService service = getService();
          try {
              return service.shouldVibrate(vibrateType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns whether the user's vibrate setting for a vibrate type.
       * <p>
       * This shouldn't be needed by most clients that want to vibrate, instead
       * see {@link #shouldVibrate(int)}.
       *
       * @param vibrateType The type of vibrate. One of
       *            {@link #VIBRATE_TYPE_NOTIFICATION} or
       *            {@link #VIBRATE_TYPE_RINGER}.
       * @return The vibrate setting, one of {@link #VIBRATE_SETTING_ON},
       *         {@link #VIBRATE_SETTING_OFF}, or
       *         {@link #VIBRATE_SETTING_ONLY_SILENT}.
       * @see #setVibrateSetting(int, int)
       * @see #shouldVibrate(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public int getVibrateSetting(int vibrateType) {
          final IAudioService service = getService();
          try {
              return service.getVibrateSetting(vibrateType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Sets the setting for when the vibrate type should vibrate.
       * <p>
       * This method should only be used by applications that replace the platform-wide
       * management of audio settings or the main telephony application.
       *
       * @param vibrateType The type of vibrate. One of
       *            {@link #VIBRATE_TYPE_NOTIFICATION} or
       *            {@link #VIBRATE_TYPE_RINGER}.
       * @param vibrateSetting The vibrate setting, one of
       *            {@link #VIBRATE_SETTING_ON},
       *            {@link #VIBRATE_SETTING_OFF}, or
       *            {@link #VIBRATE_SETTING_ONLY_SILENT}.
       * @see #getVibrateSetting(int)
       * @see #shouldVibrate(int)
       * @deprecated Applications should maintain their own vibrate policy based on
       * current ringer mode that can be queried via {@link #getRingerMode()}.
       */
      public void setVibrateSetting(int vibrateType, int vibrateSetting) {
          final IAudioService service = getService();
          try {
              service.setVibrateSetting(vibrateType, vibrateSetting);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Sets the speakerphone on or off.
       * <p>
       * This method should only be used by applications that replace the platform-wide
       * management of audio settings or the main telephony application.
       *
       * @param on set <var>true</var> to turn on speakerphone;
       *           <var>false</var> to turn it off
       */
      public void setSpeakerphoneOn(boolean on){
          final IAudioService service = getService();
          try {
              service.setSpeakerphoneOn(on);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Checks whether the speakerphone is on or off.
       *
       * @return true if speakerphone is on, false if it's off
       */
      public boolean isSpeakerphoneOn() {
          final IAudioService service = getService();
          try {
              return service.isSpeakerphoneOn();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
       }
  
      /**
       * Specifies whether the audio played by this app may or may not be captured by other apps or
       * the system.
       *
       * The default is {@link AudioAttributes#ALLOW_CAPTURE_BY_ALL}.
       *
       * There are multiple ways to set this policy:
       * <ul>
       * <li> for each track independently, see
       *    {@link AudioAttributes.Builder#setAllowedCapturePolicy(int)} </li>
       * <li> application-wide at runtime, with this method </li>
       * <li> application-wide at build time, see {@code allowAudioPlaybackCapture} in the application
       *       manifest. </li>
       * </ul>
       * The most restrictive policy is always applied.
       *
       * See {@link AudioPlaybackCaptureConfiguration} for more details on
       * which audio signals can be captured.
       *
       * @param capturePolicy one of
       *     {@link AudioAttributes#ALLOW_CAPTURE_BY_ALL},
       *     {@link AudioAttributes#ALLOW_CAPTURE_BY_SYSTEM},
       *     {@link AudioAttributes#ALLOW_CAPTURE_BY_NONE}.
       * @throws RuntimeException if the argument is not a valid value.
       */
      public void setAllowedCapturePolicy(@AudioAttributes.CapturePolicy int capturePolicy) {
          // TODO: also pass the package in case multiple packages have the same UID
          final IAudioService service = getService();
          try {
              int result = service.setAllowedCapturePolicy(capturePolicy);
              if (result != AudioSystem.AUDIO_STATUS_OK) {
                  Log.e(TAG, "Could not setAllowedCapturePolicy: " + result);
                  return;
              }
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Return the capture policy.
       * @return the capture policy set by {@link #setAllowedCapturePolicy(int)} or
       *         the default if it was not called.
       */
      @AudioAttributes.CapturePolicy
      public int getAllowedCapturePolicy() {
          int result = AudioAttributes.ALLOW_CAPTURE_BY_ALL;
          try {
              result = getService().getAllowedCapturePolicy();
          } catch (RemoteException e) {
              Log.e(TAG, "Failed to query allowed capture policy: " + e);
          }
          return result;
      }
  
      //====================================================================
      // Offload query
      /**
       * Returns whether offloaded playback of an audio format is supported on the device.
       * <p>Offloaded playback is the feature where the decoding and playback of an audio stream
       * is not competing with other software resources. In general, it is supported by dedicated
       * hardware, such as audio DSPs.
       * <p>Note that this query only provides information about the support of an audio format,
       * it does not indicate whether the resources necessary for the offloaded playback are
       * available at that instant.
       * @param format the audio format (codec, sample rate, channels) being checked.
       * @param attributes the {@link AudioAttributes} to be used for playback
       * @return true if the given audio format can be offloaded.
       */
      public static boolean isOffloadedPlaybackSupported(@NonNull AudioFormat format,
              @NonNull AudioAttributes attributes) {
          if (format == null) {
              throw new NullPointerException("Illegal null AudioFormat");
          }
          if (attributes == null) {
              throw new NullPointerException("Illegal null AudioAttributes");
          }
          return AudioSystem.isOffloadSupported(format, attributes);
      }
  
      //====================================================================
      // Bluetooth SCO control
      /**
       * Sticky broadcast intent action indicating that the Bluetooth SCO audio
       * connection state has changed. The intent contains on extra {@link #EXTRA_SCO_AUDIO_STATE}
       * indicating the new state which is either {@link #SCO_AUDIO_STATE_DISCONNECTED}
       * or {@link #SCO_AUDIO_STATE_CONNECTED}
       *
       * @see #startBluetoothSco()
       * @deprecated Use  {@link #ACTION_SCO_AUDIO_STATE_UPDATED} instead
       */
      @Deprecated
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_SCO_AUDIO_STATE_CHANGED =
              "android.media.SCO_AUDIO_STATE_CHANGED";
  
       /**
       * Sticky broadcast intent action indicating that the Bluetooth SCO audio
       * connection state has been updated.
       * <p>This intent has two extras:
       * <ul>
       *   <li> {@link #EXTRA_SCO_AUDIO_STATE} - The new SCO audio state. </li>
       *   <li> {@link #EXTRA_SCO_AUDIO_PREVIOUS_STATE}- The previous SCO audio state. </li>
       * </ul>
       * <p> EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE can be any of:
       * <ul>
       *   <li> {@link #SCO_AUDIO_STATE_DISCONNECTED}, </li>
       *   <li> {@link #SCO_AUDIO_STATE_CONNECTING} or </li>
       *   <li> {@link #SCO_AUDIO_STATE_CONNECTED}, </li>
       * </ul>
       * @see #startBluetoothSco()
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_SCO_AUDIO_STATE_UPDATED =
              "android.media.ACTION_SCO_AUDIO_STATE_UPDATED";
  
      /**
       * Extra for intent {@link #ACTION_SCO_AUDIO_STATE_CHANGED} or
       * {@link #ACTION_SCO_AUDIO_STATE_UPDATED} containing the new bluetooth SCO connection state.
       */
      public static final String EXTRA_SCO_AUDIO_STATE =
              "android.media.extra.SCO_AUDIO_STATE";
  
      /**
       * Extra for intent {@link #ACTION_SCO_AUDIO_STATE_UPDATED} containing the previous
       * bluetooth SCO connection state.
       */
      public static final String EXTRA_SCO_AUDIO_PREVIOUS_STATE =
              "android.media.extra.SCO_AUDIO_PREVIOUS_STATE";
  
      /**
       * Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE
       * indicating that the SCO audio channel is not established
       */
      public static final int SCO_AUDIO_STATE_DISCONNECTED = 0;
      /**
       * Value for extra {@link #EXTRA_SCO_AUDIO_STATE} or {@link #EXTRA_SCO_AUDIO_PREVIOUS_STATE}
       * indicating that the SCO audio channel is established
       */
      public static final int SCO_AUDIO_STATE_CONNECTED = 1;
      /**
       * Value for extra EXTRA_SCO_AUDIO_STATE or EXTRA_SCO_AUDIO_PREVIOUS_STATE
       * indicating that the SCO audio channel is being established
       */
      public static final int SCO_AUDIO_STATE_CONNECTING = 2;
      /**
       * Value for extra EXTRA_SCO_AUDIO_STATE indicating that
       * there was an error trying to obtain the state
       */
      public static final int SCO_AUDIO_STATE_ERROR = -1;
  
  
      /**
       * Indicates if current platform supports use of SCO for off call use cases.
       * Application wanted to use bluetooth SCO audio when the phone is not in call
       * must first call this method to make sure that the platform supports this
       * feature.
       * @return true if bluetooth SCO can be used for audio when not in call
       *         false otherwise
       * @see #startBluetoothSco()
      */
      public boolean isBluetoothScoAvailableOffCall() {
          return getContext().getResources().getBoolean(
                 com.android.internal.R.bool.config_bluetooth_sco_off_call);
      }
  
      /**
       * Start bluetooth SCO audio connection.
       * <p>Requires Permission:
       *   {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}.
       * <p>This method can be used by applications wanting to send and received audio
       * to/from a bluetooth SCO headset while the phone is not in call.
       * <p>As the SCO connection establishment can take several seconds,
       * applications should not rely on the connection to be available when the method
       * returns but instead register to receive the intent {@link #ACTION_SCO_AUDIO_STATE_UPDATED}
       * and wait for the state to be {@link #SCO_AUDIO_STATE_CONNECTED}.
       * <p>As the ACTION_SCO_AUDIO_STATE_UPDATED intent is sticky, the application can check the SCO
       * audio state before calling startBluetoothSco() by reading the intent returned by the receiver
       * registration. If the state is already CONNECTED, no state change will be received via the
       * intent after calling startBluetoothSco(). It is however useful to call startBluetoothSco()
       * so that the connection stays active in case the current initiator stops the connection.
       * <p>Unless the connection is already active as described above, the state will always
       * transition from DISCONNECTED to CONNECTING and then either to CONNECTED if the connection
       * succeeds or back to DISCONNECTED if the connection fails (e.g no headset is connected).
       * <p>When finished with the SCO connection or if the establishment fails, the application must
       * call {@link #stopBluetoothSco()} to clear the request and turn down the bluetooth connection.
       * <p>Even if a SCO connection is established, the following restrictions apply on audio
       * output streams so that they can be routed to SCO headset:
       * <ul>
       *   <li> the stream type must be {@link #STREAM_VOICE_CALL} </li>
       *   <li> the format must be mono </li>
       *   <li> the sampling must be 16kHz or 8kHz </li>
       * </ul>
       * <p>The following restrictions apply on input streams:
       * <ul>
       *   <li> the format must be mono </li>
       *   <li> the sampling must be 8kHz </li>
       * </ul>
       * <p>Note that the phone application always has the priority on the usage of the SCO
       * connection for telephony. If this method is called while the phone is in call
       * it will be ignored. Similarly, if a call is received or sent while an application
       * is using the SCO connection, the connection will be lost for the application and NOT
       * returned automatically when the call ends.
       * <p>NOTE: up to and including API version
       * {@link android.os.Build.VERSION_CODES#JELLY_BEAN_MR1}, this method initiates a virtual
       * voice call to the bluetooth headset.
       * After API version {@link android.os.Build.VERSION_CODES#JELLY_BEAN_MR2} only a raw SCO audio
       * connection is established.
       * @see #stopBluetoothSco()
       * @see #ACTION_SCO_AUDIO_STATE_UPDATED
       */
      public void startBluetoothSco(){
          final IAudioService service = getService();
          try {
              service.startBluetoothSco(mICallBack,
                      getContext().getApplicationInfo().targetSdkVersion);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Start bluetooth SCO audio connection in virtual call mode.
       * <p>Requires Permission:
       *   {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}.
       * <p>Similar to {@link #startBluetoothSco()} with explicit selection of virtual call mode.
       * Telephony and communication applications (VoIP, Video Chat) should preferably select
       * virtual call mode.
       * Applications using voice input for search or commands should first try raw audio connection
       * with {@link #startBluetoothSco()} and fall back to startBluetoothScoVirtualCall() in case of
       * failure.
       * @see #startBluetoothSco()
       * @see #stopBluetoothSco()
       * @see #ACTION_SCO_AUDIO_STATE_UPDATED
       */
      @UnsupportedAppUsage
      public void startBluetoothScoVirtualCall() {
          final IAudioService service = getService();
          try {
              service.startBluetoothScoVirtualCall(mICallBack);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Stop bluetooth SCO audio connection.
       * <p>Requires Permission:
       *   {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}.
       * <p>This method must be called by applications having requested the use of
       * bluetooth SCO audio with {@link #startBluetoothSco()} when finished with the SCO
       * connection or if connection fails.
       * @see #startBluetoothSco()
       */
      // Also used for connections started with {@link #startBluetoothScoVirtualCall()}
      public void stopBluetoothSco(){
          final IAudioService service = getService();
          try {
              service.stopBluetoothSco(mICallBack);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Request use of Bluetooth SCO headset for communications.
       * <p>
       * This method should only be used by applications that replace the platform-wide
       * management of audio settings or the main telephony application.
       *
       * @param on set <var>true</var> to use bluetooth SCO for communications;
       *               <var>false</var> to not use bluetooth SCO for communications
       */
      public void setBluetoothScoOn(boolean on){
          final IAudioService service = getService();
          try {
              service.setBluetoothScoOn(on);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Checks whether communications use Bluetooth SCO.
       *
       * @return true if SCO is used for communications;
       *         false if otherwise
       */
      public boolean isBluetoothScoOn() {
          final IAudioService service = getService();
          try {
              return service.isBluetoothScoOn();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @param on set <var>true</var> to route A2DP audio to/from Bluetooth
       *           headset; <var>false</var> disable A2DP audio
       * @deprecated Do not use.
       */
      @Deprecated public void setBluetoothA2dpOn(boolean on){
      }
  
      /**
       * Checks whether a Bluetooth A2DP audio peripheral is connected or not.
       *
       * @return true if a Bluetooth A2DP peripheral is connected
       *         false if otherwise
       * @deprecated Use {@link AudioManager#getDevices(int)} instead to list available audio devices.
       */
      public boolean isBluetoothA2dpOn() {
          if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_BLUETOOTH_A2DP,"")
                  == AudioSystem.DEVICE_STATE_AVAILABLE) {
              return true;
          } else if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES,"")
                  == AudioSystem.DEVICE_STATE_AVAILABLE) {
              return true;
          } else if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER,"")
                  == AudioSystem.DEVICE_STATE_AVAILABLE) {
              return true;
          }
          return false;
      }
  
      /**
       * Sets audio routing to the wired headset on or off.
       *
       * @param on set <var>true</var> to route audio to/from wired
       *           headset; <var>false</var> disable wired headset audio
       * @deprecated Do not use.
       */
      @Deprecated public void setWiredHeadsetOn(boolean on){
      }
  
      /**
       * Checks whether a wired headset is connected or not.
       * <p>This is not a valid indication that audio playback is
       * actually over the wired headset as audio routing depends on other conditions.
       *
       * @return true if a wired headset is connected.
       *         false if otherwise
       * @deprecated Use {@link AudioManager#getDevices(int)} instead to list available audio devices.
       */
      public boolean isWiredHeadsetOn() {
          if (AudioSystem.getDeviceConnectionState(DEVICE_OUT_WIRED_HEADSET,"")
                  == AudioSystem.DEVICE_STATE_UNAVAILABLE &&
              AudioSystem.getDeviceConnectionState(DEVICE_OUT_WIRED_HEADPHONE,"")
                  == AudioSystem.DEVICE_STATE_UNAVAILABLE &&
              AudioSystem.getDeviceConnectionState(DEVICE_OUT_USB_HEADSET, "")
                == AudioSystem.DEVICE_STATE_UNAVAILABLE) {
              return false;
          } else {
              return true;
          }
      }
  
      /**
       * Sets the microphone mute on or off.
       * <p>
       * This method should only be used by applications that replace the platform-wide
       * management of audio settings or the main telephony application.
       *
       * @param on set <var>true</var> to mute the microphone;
       *           <var>false</var> to turn mute off
       */
      public void setMicrophoneMute(boolean on) {
          final IAudioService service = getService();
          try {
              service.setMicrophoneMute(on, getContext().getOpPackageName(),
                      UserHandle.getCallingUserId());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Checks whether the microphone mute is on or off.
       *
       * @return true if microphone is muted, false if it's not
       */
      public boolean isMicrophoneMute() {
          return AudioSystem.isMicrophoneMuted();
      }
  
      /**
       * Broadcast Action: microphone muting state changed.
       *
       * You <em>cannot</em> receive this through components declared
       * in manifests, only by explicitly registering for it with
       * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)
       * Context.registerReceiver()}.
       *
       * <p>The intent has no extra values, use {@link #isMicrophoneMute} to check whether the
       * microphone is muted.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_MICROPHONE_MUTE_CHANGED =
              "android.media.action.MICROPHONE_MUTE_CHANGED";
  
      /**
       * Broadcast Action: speakerphone state changed.
       *
       * You <em>cannot</em> receive this through components declared
       * in manifests, only by explicitly registering for it with
       * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)
       * Context.registerReceiver()}.
       *
       * <p>The intent has no extra values, use {@link #isSpeakerphoneOn} to check whether the
       * speakerphone functionality is enabled or not.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
      public static final String ACTION_SPEAKERPHONE_STATE_CHANGED =
              "android.media.action.SPEAKERPHONE_STATE_CHANGED";
  
      /**
       * Sets the audio mode.
       * <p>
       * The audio mode encompasses audio routing AND the behavior of
       * the telephony layer. Therefore this method should only be used by applications that
       * replace the platform-wide management of audio settings or the main telephony application.
       * In particular, the {@link #MODE_IN_CALL} mode should only be used by the telephony
       * application when it places a phone call, as it will cause signals from the radio layer
       * to feed the platform mixer.
       *
       * @param mode  the requested audio mode ({@link #MODE_NORMAL}, {@link #MODE_RINGTONE},
       *              {@link #MODE_IN_CALL} or {@link #MODE_IN_COMMUNICATION}).
       *              Informs the HAL about the current audio state so that
       *              it can route the audio appropriately.
       */
      public void setMode(int mode) {
          final IAudioService service = getService();
          try {
              service.setMode(mode, mICallBack, mApplicationContext.getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns the current audio mode.
       *
       * @return      the current audio mode ({@link #MODE_NORMAL}, {@link #MODE_RINGTONE},
       *              {@link #MODE_IN_CALL} or {@link #MODE_IN_COMMUNICATION}).
       *              Returns the current current audio state from the HAL.
       */
      public int getMode() {
          final IAudioService service = getService();
          try {
              return service.getMode();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /* modes for setMode/getMode/setRoute/getRoute */
      /**
       * Audio harware modes.
       */
      /**
       * Invalid audio mode.
       */
      public static final int MODE_INVALID            = AudioSystem.MODE_INVALID;
      /**
       * Current audio mode. Used to apply audio routing to current mode.
       */
      public static final int MODE_CURRENT            = AudioSystem.MODE_CURRENT;
      /**
       * Normal audio mode: not ringing and no call established.
       */
      public static final int MODE_NORMAL             = AudioSystem.MODE_NORMAL;
      /**
       * Ringing audio mode. An incoming is being signaled.
       */
      public static final int MODE_RINGTONE           = AudioSystem.MODE_RINGTONE;
      /**
       * In call audio mode. A telephony call is established.
       */
      public static final int MODE_IN_CALL            = AudioSystem.MODE_IN_CALL;
      /**
       * In communication audio mode. An audio/video chat or VoIP call is established.
       */
      public static final int MODE_IN_COMMUNICATION   = AudioSystem.MODE_IN_COMMUNICATION;
  
      /* Routing bits for setRouting/getRouting API */
      /**
       * Routing audio output to earpiece
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_EARPIECE          = AudioSystem.ROUTE_EARPIECE;
      /**
       * Routing audio output to speaker
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_SPEAKER           = AudioSystem.ROUTE_SPEAKER;
      /**
       * @deprecated use {@link #ROUTE_BLUETOOTH_SCO}
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_BLUETOOTH = AudioSystem.ROUTE_BLUETOOTH_SCO;
      /**
       * Routing audio output to bluetooth SCO
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_BLUETOOTH_SCO     = AudioSystem.ROUTE_BLUETOOTH_SCO;
      /**
       * Routing audio output to headset
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_HEADSET           = AudioSystem.ROUTE_HEADSET;
      /**
       * Routing audio output to bluetooth A2DP
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_BLUETOOTH_A2DP    = AudioSystem.ROUTE_BLUETOOTH_A2DP;
      /**
       * Used for mask parameter of {@link #setRouting(int,int,int)}.
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated public static final int ROUTE_ALL               = AudioSystem.ROUTE_ALL;
  
      /**
       * Sets the audio routing for a specified mode
       *
       * @param mode   audio mode to change route. E.g., MODE_RINGTONE.
       * @param routes bit vector of routes requested, created from one or
       *               more of ROUTE_xxx types. Set bits indicate that route should be on
       * @param mask   bit vector of routes to change, created from one or more of
       * ROUTE_xxx types. Unset bits indicate the route should be left unchanged
       *
       * @deprecated   Do not set audio routing directly, use setSpeakerphoneOn(),
       * setBluetoothScoOn() methods instead.
       */
      @Deprecated
      public void setRouting(int mode, int routes, int mask) {
      }
  
      /**
       * Returns the current audio routing bit vector for a specified mode.
       *
       * @param mode audio mode to get route (e.g., MODE_RINGTONE)
       * @return an audio route bit vector that can be compared with ROUTE_xxx
       * bits
       * @deprecated   Do not query audio routing directly, use isSpeakerphoneOn(),
       * isBluetoothScoOn(), isBluetoothA2dpOn() and isWiredHeadsetOn() methods instead.
       */
      @Deprecated
      public int getRouting(int mode) {
          return -1;
      }
  
      /**
       * Checks whether any music is active.
       *
       * @return true if any music tracks are active.
       */
      public boolean isMusicActive() {
          return AudioSystem.isStreamActive(STREAM_MUSIC, 0);
      }
  
      /**
       * @hide
       * Checks whether any music or media is actively playing on a remote device (e.g. wireless
       *   display). Note that BT audio sinks are not considered remote devices.
       * @return true if {@link AudioManager#STREAM_MUSIC} is active on a remote device
       */
      @UnsupportedAppUsage
      public boolean isMusicActiveRemotely() {
          return AudioSystem.isStreamActiveRemotely(STREAM_MUSIC, 0);
      }
  
      /**
       * @hide
       * Checks whether the current audio focus is exclusive.
       * @return true if the top of the audio focus stack requested focus
       *     with {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE}
       */
      public boolean isAudioFocusExclusive() {
          final IAudioService service = getService();
          try {
              return service.getCurrentAudioFocus() == AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE;
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Return a new audio session identifier not associated with any player or effect.
       * An audio session identifier is a system wide unique identifier for a set of audio streams
       * (one or more mixed together).
       * <p>The primary use of the audio session ID is to associate audio effects to audio players,
       * such as {@link MediaPlayer} or {@link AudioTrack}: all audio effects sharing the same audio
       * session ID will be applied to the mixed audio content of the players that share the same
       * audio session.
       * <p>This method can for instance be used when creating one of the
       * {@link android.media.audiofx.AudioEffect} objects to define the audio session of the effect,
       * or to specify a session for a speech synthesis utterance
       * in {@link android.speech.tts.TextToSpeech.Engine}.
       * @return a new unclaimed and unused audio session identifier, or {@link #ERROR} when the
       *   system failed to generate a new session, a condition in which audio playback or recording
       *   will subsequently fail as well.
       */
      public int generateAudioSessionId() {
          int session = AudioSystem.newAudioSessionId();
          if (session > 0) {
              return session;
          } else {
              Log.e(TAG, "Failure to generate a new audio session ID");
              return ERROR;
          }
      }
  
      /**
       * A special audio session ID to indicate that the audio session ID isn't known and the
       * framework should generate a new value. This can be used when building a new
       * {@link AudioTrack} instance with
       * {@link AudioTrack#AudioTrack(AudioAttributes, AudioFormat, int, int, int)}.
       */
      public static final int AUDIO_SESSION_ID_GENERATE = AudioSystem.AUDIO_SESSION_ALLOCATE;
  
  
      /*
       * Sets a generic audio configuration parameter. The use of these parameters
       * are platform dependant, see libaudio
       *
       * ** Temporary interface - DO NOT USE
       *
       * TODO: Replace with a more generic key:value get/set mechanism
       *
       * param key   name of parameter to set. Must not be null.
       * param value value of parameter. Must not be null.
       */
      /**
       * @hide
       * @deprecated Use {@link #setParameters(String)} instead
       */
      @Deprecated public void setParameter(String key, String value) {
          setParameters(key+"="+value);
      }
  
      /**
       * Sets a variable number of parameter values to audio hardware.
       *
       * @param keyValuePairs list of parameters key value pairs in the form:
       *    key1=value1;key2=value2;...
       *
       */
      public void setParameters(String keyValuePairs) {
          AudioSystem.setParameters(keyValuePairs);
      }
  
      /**
       * Gets a variable number of parameter values from audio hardware.
       *
       * @param keys list of parameters
       * @return list of parameters key value pairs in the form:
       *    key1=value1;key2=value2;...
       */
      public String getParameters(String keys) {
          return AudioSystem.getParameters(keys);
      }
  
      /* Sound effect identifiers */
      /**
       * Keyboard and direction pad click sound
       * @see #playSoundEffect(int)
       */
      public static final int FX_KEY_CLICK = 0;
      /**
       * Focus has moved up
       * @see #playSoundEffect(int)
       */
      public static final int FX_FOCUS_NAVIGATION_UP = 1;
      /**
       * Focus has moved down
       * @see #playSoundEffect(int)
       */
      public static final int FX_FOCUS_NAVIGATION_DOWN = 2;
      /**
       * Focus has moved left
       * @see #playSoundEffect(int)
       */
      public static final int FX_FOCUS_NAVIGATION_LEFT = 3;
      /**
       * Focus has moved right
       * @see #playSoundEffect(int)
       */
      public static final int FX_FOCUS_NAVIGATION_RIGHT = 4;
      /**
       * IME standard keypress sound
       * @see #playSoundEffect(int)
       */
      public static final int FX_KEYPRESS_STANDARD = 5;
      /**
       * IME spacebar keypress sound
       * @see #playSoundEffect(int)
       */
      public static final int FX_KEYPRESS_SPACEBAR = 6;
      /**
       * IME delete keypress sound
       * @see #playSoundEffect(int)
       */
      public static final int FX_KEYPRESS_DELETE = 7;
      /**
       * IME return_keypress sound
       * @see #playSoundEffect(int)
       */
      public static final int FX_KEYPRESS_RETURN = 8;
  
      /**
       * Invalid keypress sound
       * @see #playSoundEffect(int)
       */
      public static final int FX_KEYPRESS_INVALID = 9;
      /**
       * @hide Number of sound effects
       */
      @UnsupportedAppUsage
      public static final int NUM_SOUND_EFFECTS = 10;
  
      /**
       * Plays a sound effect (Key clicks, lid open/close...)
       * @param effectType The type of sound effect. One of
       *            {@link #FX_KEY_CLICK},
       *            {@link #FX_FOCUS_NAVIGATION_UP},
       *            {@link #FX_FOCUS_NAVIGATION_DOWN},
       *            {@link #FX_FOCUS_NAVIGATION_LEFT},
       *            {@link #FX_FOCUS_NAVIGATION_RIGHT},
       *            {@link #FX_KEYPRESS_STANDARD},
       *            {@link #FX_KEYPRESS_SPACEBAR},
       *            {@link #FX_KEYPRESS_DELETE},
       *            {@link #FX_KEYPRESS_RETURN},
       *            {@link #FX_KEYPRESS_INVALID},
       * NOTE: This version uses the UI settings to determine
       * whether sounds are heard or not.
       */
      public void  playSoundEffect(int effectType) {
          if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
              return;
          }
  
          if (!querySoundEffectsEnabled(Process.myUserHandle().getIdentifier())) {
              return;
          }
  
          final IAudioService service = getService();
          try {
              service.playSoundEffect(effectType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Plays a sound effect (Key clicks, lid open/close...)
       * @param effectType The type of sound effect. One of
       *            {@link #FX_KEY_CLICK},
       *            {@link #FX_FOCUS_NAVIGATION_UP},
       *            {@link #FX_FOCUS_NAVIGATION_DOWN},
       *            {@link #FX_FOCUS_NAVIGATION_LEFT},
       *            {@link #FX_FOCUS_NAVIGATION_RIGHT},
       *            {@link #FX_KEYPRESS_STANDARD},
       *            {@link #FX_KEYPRESS_SPACEBAR},
       *            {@link #FX_KEYPRESS_DELETE},
       *            {@link #FX_KEYPRESS_RETURN},
       *            {@link #FX_KEYPRESS_INVALID},
       * @param userId The current user to pull sound settings from
       * NOTE: This version uses the UI settings to determine
       * whether sounds are heard or not.
       * @hide
       */
      public void  playSoundEffect(int effectType, int userId) {
          if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
              return;
          }
  
          if (!querySoundEffectsEnabled(userId)) {
              return;
          }
  
          final IAudioService service = getService();
          try {
              service.playSoundEffect(effectType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Plays a sound effect (Key clicks, lid open/close...)
       * @param effectType The type of sound effect. One of
       *            {@link #FX_KEY_CLICK},
       *            {@link #FX_FOCUS_NAVIGATION_UP},
       *            {@link #FX_FOCUS_NAVIGATION_DOWN},
       *            {@link #FX_FOCUS_NAVIGATION_LEFT},
       *            {@link #FX_FOCUS_NAVIGATION_RIGHT},
       *            {@link #FX_KEYPRESS_STANDARD},
       *            {@link #FX_KEYPRESS_SPACEBAR},
       *            {@link #FX_KEYPRESS_DELETE},
       *            {@link #FX_KEYPRESS_RETURN},
       *            {@link #FX_KEYPRESS_INVALID},
       * @param volume Sound effect volume.
       * The volume value is a raw scalar so UI controls should be scaled logarithmically.
       * If a volume of -1 is specified, the AudioManager.STREAM_MUSIC stream volume minus 3dB will be used.
       * NOTE: This version is for applications that have their own
       * settings panel for enabling and controlling volume.
       */
      public void  playSoundEffect(int effectType, float volume) {
          if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
              return;
          }
  
          final IAudioService service = getService();
          try {
              service.playSoundEffectVolume(effectType, volume);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Settings has an in memory cache, so this is fast.
       */
      private boolean querySoundEffectsEnabled(int user) {
          return Settings.System.getIntForUser(getContext().getContentResolver(),
                  Settings.System.SOUND_EFFECTS_ENABLED, 0, user) != 0;
      }
  
      /**
       *  Load Sound effects.
       *  This method must be called when sound effects are enabled.
       */
      public void loadSoundEffects() {
          final IAudioService service = getService();
          try {
              service.loadSoundEffects();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       *  Unload Sound effects.
       *  This method can be called to free some memory when
       *  sound effects are disabled.
       */
      public void unloadSoundEffects() {
          final IAudioService service = getService();
          try {
              service.unloadSoundEffects();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Used to indicate no audio focus has been gained or lost, or requested.
       */
      public static final int AUDIOFOCUS_NONE = 0;
  
      /**
       * Used to indicate a gain of audio focus, or a request of audio focus, of unknown duration.
       * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
       * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
       */
      public static final int AUDIOFOCUS_GAIN = 1;
      /**
       * Used to indicate a temporary gain or request of audio focus, anticipated to last a short
       * amount of time. Examples of temporary changes are the playback of driving directions, or an
       * event notification.
       * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
       * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
       */
      public static final int AUDIOFOCUS_GAIN_TRANSIENT = 2;
      /**
       * Used to indicate a temporary request of audio focus, anticipated to last a short
       * amount of time, and where it is acceptable for other audio applications to keep playing
       * after having lowered their output level (also referred to as "ducking").
       * Examples of temporary changes are the playback of driving directions where playback of music
       * in the background is acceptable.
       * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
       * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
       */
      public static final int AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK = 3;
      /**
       * Used to indicate a temporary request of audio focus, anticipated to last a short
       * amount of time, during which no other applications, or system components, should play
       * anything. Examples of exclusive and transient audio focus requests are voice
       * memo recording and speech recognition, during which the system shouldn't play any
       * notifications, and media playback should have paused.
       * @see #requestAudioFocus(OnAudioFocusChangeListener, int, int)
       */
      public static final int AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE = 4;
      /**
       * Used to indicate a loss of audio focus of unknown duration.
       * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
       */
      public static final int AUDIOFOCUS_LOSS = -1 * AUDIOFOCUS_GAIN;
      /**
       * Used to indicate a transient loss of audio focus.
       * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
       */
      public static final int AUDIOFOCUS_LOSS_TRANSIENT = -1 * AUDIOFOCUS_GAIN_TRANSIENT;
      /**
       * Used to indicate a transient loss of audio focus where the loser of the audio focus can
       * lower its output volume if it wants to continue playing (also referred to as "ducking"), as
       * the new focus owner doesn't require others to be silent.
       * @see OnAudioFocusChangeListener#onAudioFocusChange(int)
       */
      public static final int AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK =
              -1 * AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK;
  
      /**
       * Interface definition for a callback to be invoked when the audio focus of the system is
       * updated.
       */
      public interface OnAudioFocusChangeListener {
          /**
           * Called on the listener to notify it the audio focus for this listener has been changed.
           * The focusChange value indicates whether the focus was gained,
           * whether the focus was lost, and whether that loss is transient, or whether the new focus
           * holder will hold it for an unknown amount of time.
           * When losing focus, listeners can use the focus change information to decide what
           * behavior to adopt when losing focus. A music player could for instance elect to lower
           * the volume of its music stream (duck) for transient focus losses, and pause otherwise.
           * @param focusChange the type of focus change, one of {@link AudioManager#AUDIOFOCUS_GAIN},
           *   {@link AudioManager#AUDIOFOCUS_LOSS}, {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT}
           *   and {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK}.
           */
          public void onAudioFocusChange(int focusChange);
      }
  
      /**
       * Internal class to hold the AudioFocusRequest as well as the Handler for the callback
       */
      private static class FocusRequestInfo {
          @NonNull  final AudioFocusRequest mRequest;
          @Nullable final Handler mHandler;
          FocusRequestInfo(@NonNull AudioFocusRequest afr, @Nullable Handler handler) {
              mRequest = afr;
              mHandler = handler;
          }
      }
  
      /**
       * Map to convert focus event listener IDs, as used in the AudioService audio focus stack,
       * to actual listener objects.
       */
      @UnsupportedAppUsage
      private final ConcurrentHashMap<String, FocusRequestInfo> mAudioFocusIdListenerMap =
              new ConcurrentHashMap<String, FocusRequestInfo>();
  
      private FocusRequestInfo findFocusRequestInfo(String id) {
          return mAudioFocusIdListenerMap.get(id);
      }
  
      /**
       * Handler for events (audio focus change, recording config change) coming from the
       * audio service.
       */
      private final ServiceEventHandlerDelegate mServiceEventHandlerDelegate =
              new ServiceEventHandlerDelegate(null);
  
      /**
       * Event types
       */
      private final static int MSSG_FOCUS_CHANGE = 0;
      private final static int MSSG_RECORDING_CONFIG_CHANGE = 1;
      private final static int MSSG_PLAYBACK_CONFIG_CHANGE = 2;
  
      /**
       * Helper class to handle the forwarding of audio service events to the appropriate listener
       */
      private class ServiceEventHandlerDelegate {
          private final Handler mHandler;
  
          ServiceEventHandlerDelegate(Handler handler) {
              Looper looper;
              if (handler == null) {
                  if ((looper = Looper.myLooper()) == null) {
                      looper = Looper.getMainLooper();
                  }
              } else {
                  looper = handler.getLooper();
              }
  
              if (looper != null) {
                  // implement the event handler delegate to receive events from audio service
                  mHandler = new Handler(looper) {
                      @Override
                      public void handleMessage(Message msg) {
                          switch (msg.what) {
                              case MSSG_FOCUS_CHANGE: {
                                  final FocusRequestInfo fri = findFocusRequestInfo((String)msg.obj);
                                  if (fri != null)  {
                                      final OnAudioFocusChangeListener listener =
                                              fri.mRequest.getOnAudioFocusChangeListener();
                                      if (listener != null) {
                                          Log.d(TAG, "dispatching onAudioFocusChange("
                                                  + msg.arg1 + ") to " + msg.obj);
                                          listener.onAudioFocusChange(msg.arg1);
                                      }
                                  }
                              } break;
                              case MSSG_RECORDING_CONFIG_CHANGE: {
                                  final RecordConfigChangeCallbackData cbData =
                                          (RecordConfigChangeCallbackData) msg.obj;
                                  if (cbData.mCb != null) {
                                      cbData.mCb.onRecordingConfigChanged(cbData.mConfigs);
                                  }
                              } break;
                              case MSSG_PLAYBACK_CONFIG_CHANGE: {
                                  final PlaybackConfigChangeCallbackData cbData =
                                          (PlaybackConfigChangeCallbackData) msg.obj;
                                  if (cbData.mCb != null) {
                                      if (DEBUG) {
                                          Log.d(TAG, "dispatching onPlaybackConfigChanged()");
                                      }
                                      cbData.mCb.onPlaybackConfigChanged(cbData.mConfigs);
                                  }
                              } break;
                              default:
                                  Log.e(TAG, "Unknown event " + msg.what);
                          }
                      }
                  };
              } else {
                  mHandler = null;
              }
          }
  
          Handler getHandler() {
              return mHandler;
          }
      }
  
      private final IAudioFocusDispatcher mAudioFocusDispatcher = new IAudioFocusDispatcher.Stub() {
          @Override
          public void dispatchAudioFocusChange(int focusChange, String id) {
              final FocusRequestInfo fri = findFocusRequestInfo(id);
              if (fri != null)  {
                  final OnAudioFocusChangeListener listener =
                          fri.mRequest.getOnAudioFocusChangeListener();
                  if (listener != null) {
                      final Handler h = (fri.mHandler == null) ?
                              mServiceEventHandlerDelegate.getHandler() : fri.mHandler;
                      final Message m = h.obtainMessage(
                              MSSG_FOCUS_CHANGE/*what*/, focusChange/*arg1*/, 0/*arg2 ignored*/,
                              id/*obj*/);
                      h.sendMessage(m);
                  }
              }
          }
  
          @Override
          public void dispatchFocusResultFromExtPolicy(int requestResult, String clientId) {
              synchronized (mFocusRequestsLock) {
                  // TODO use generation counter as the key instead
                  final BlockingFocusResultReceiver focusReceiver =
                          mFocusRequestsAwaitingResult.remove(clientId);
                  if (focusReceiver != null) {
                      focusReceiver.notifyResult(requestResult);
                  } else {
                      Log.e(TAG, "dispatchFocusResultFromExtPolicy found no result receiver");
                  }
              }
          }
      };
  
      private String getIdForAudioFocusListener(OnAudioFocusChangeListener l) {
          if (l == null) {
              return new String(this.toString());
          } else {
              return new String(this.toString() + l.toString());
          }
      }
  
      /**
       * @hide
       * Registers a listener to be called when audio focus changes and keeps track of the associated
       * focus request (including Handler to use for the listener).
       * @param afr the full request parameters
       */
      public void registerAudioFocusRequest(@NonNull AudioFocusRequest afr) {
          final Handler h = afr.getOnAudioFocusChangeListenerHandler();
          final FocusRequestInfo fri = new FocusRequestInfo(afr, (h == null) ? null :
              new ServiceEventHandlerDelegate(h).getHandler());
          final String key = getIdForAudioFocusListener(afr.getOnAudioFocusChangeListener());
          mAudioFocusIdListenerMap.put(key, fri);
      }
  
      /**
       * @hide
       * Causes the specified listener to not be called anymore when focus is gained or lost.
       * @param l the listener to unregister.
       */
      public void unregisterAudioFocusRequest(OnAudioFocusChangeListener l) {
          // remove locally
          mAudioFocusIdListenerMap.remove(getIdForAudioFocusListener(l));
      }
  
  
      /**
       * A failed focus change request.
       */
      public static final int AUDIOFOCUS_REQUEST_FAILED = 0;
      /**
       * A successful focus change request.
       */
      public static final int AUDIOFOCUS_REQUEST_GRANTED = 1;
       /**
        * A focus change request whose granting is delayed: the request was successful, but the
        * requester will only be granted audio focus once the condition that prevented immediate
        * granting has ended.
        * See {@link #requestAudioFocus(AudioFocusRequest)} and
        * {@link AudioFocusRequest.Builder#setAcceptsDelayedFocusGain(boolean)}
        */
      public static final int AUDIOFOCUS_REQUEST_DELAYED = 2;
  
      /** @hide */
      @IntDef(flag = false, prefix = "AUDIOFOCUS_REQUEST", value = {
              AUDIOFOCUS_REQUEST_FAILED,
              AUDIOFOCUS_REQUEST_GRANTED,
              AUDIOFOCUS_REQUEST_DELAYED }
      )
      @Retention(RetentionPolicy.SOURCE)
      public @interface FocusRequestResult {}
  
      /**
       * @hide
       * code returned when a synchronous focus request on the client-side is to be blocked
       * until the external audio focus policy decides on the response for the client
       */
      public static final int AUDIOFOCUS_REQUEST_WAITING_FOR_EXT_POLICY = 100;
  
      /**
       * Timeout duration in ms when waiting on an external focus policy for the result for a
       * focus request
       */
      private static final int EXT_FOCUS_POLICY_TIMEOUT_MS = 200;
  
      private static final String FOCUS_CLIENT_ID_STRING = "android_audio_focus_client_id";
  
      private final Object mFocusRequestsLock = new Object();
      /**
       * Map of all receivers of focus request results, one per unresolved focus request.
       * Receivers are added before sending the request to the external focus policy,
       * and are removed either after receiving the result, or after the timeout.
       * This variable is lazily initialized.
       */
      @GuardedBy("mFocusRequestsLock")
      private HashMap<String, BlockingFocusResultReceiver> mFocusRequestsAwaitingResult;
  
  
      /**
       *  Request audio focus.
       *  Send a request to obtain the audio focus
       *  @param l the listener to be notified of audio focus changes
       *  @param streamType the main audio stream type affected by the focus request
       *  @param durationHint use {@link #AUDIOFOCUS_GAIN_TRANSIENT} to indicate this focus request
       *      is temporary, and focus will be abandonned shortly. Examples of transient requests are
       *      for the playback of driving directions, or notifications sounds.
       *      Use {@link #AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK} to indicate also that it's ok for
       *      the previous focus owner to keep playing if it ducks its audio output.
       *      Alternatively use {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE} for a temporary request
       *      that benefits from the system not playing disruptive sounds like notifications, for
       *      usecases such as voice memo recording, or speech recognition.
       *      Use {@link #AUDIOFOCUS_GAIN} for a focus request of unknown duration such
       *      as the playback of a song or a video.
       *  @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
       *  @deprecated use {@link #requestAudioFocus(AudioFocusRequest)}
       */
      public int requestAudioFocus(OnAudioFocusChangeListener l, int streamType, int durationHint) {
          PlayerBase.deprecateStreamTypeForPlayback(streamType,
                  "AudioManager", "requestAudioFocus()");
          int status = AUDIOFOCUS_REQUEST_FAILED;
  
          try {
              // status is guaranteed to be either AUDIOFOCUS_REQUEST_FAILED or
              // AUDIOFOCUS_REQUEST_GRANTED as focus is requested without the
              // AUDIOFOCUS_FLAG_DELAY_OK flag
              status = requestAudioFocus(l,
                      new AudioAttributes.Builder()
                              .setInternalLegacyStreamType(streamType).build(),
                      durationHint,
                      0 /* flags, legacy behavior */);
          } catch (IllegalArgumentException e) {
              Log.e(TAG, "Audio focus request denied due to ", e);
          }
  
          return status;
      }
  
      // when adding new flags, add them to the relevant AUDIOFOCUS_FLAGS_APPS or SYSTEM masks
      /**
       * @hide
       * Use this flag when requesting audio focus to indicate it is ok for the requester to not be
       * granted audio focus immediately (as indicated by {@link #AUDIOFOCUS_REQUEST_DELAYED}) when
       * the system is in a state where focus cannot change, but be granted focus later when
       * this condition ends.
       */
      @SystemApi
      public static final int AUDIOFOCUS_FLAG_DELAY_OK = 0x1 << 0;
      /**
       * @hide
       * Use this flag when requesting audio focus to indicate that the requester
       * will pause its media playback (if applicable) when losing audio focus with
       * {@link #AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK}, rather than ducking.
       * <br>On some platforms, the ducking may be handled without the application being aware of it
       * (i.e. it will not transiently lose focus). For applications that for instance play spoken
       * content, such as audio book or podcast players, ducking may never be acceptable, and will
       * thus always pause. This flag enables them to be declared as such whenever they request focus.
       */
      @SystemApi
      public static final int AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS = 0x1 << 1;
      /**
       * @hide
       * Use this flag to lock audio focus so granting is temporarily disabled.
       * <br>This flag can only be used by owners of a registered
       * {@link android.media.audiopolicy.AudioPolicy} in
       * {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int, AudioPolicy)}
       */
      @SystemApi
      public static final int AUDIOFOCUS_FLAG_LOCK     = 0x1 << 2;
      /** @hide */
      public static final int AUDIOFOCUS_FLAGS_APPS = AUDIOFOCUS_FLAG_DELAY_OK
              | AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS;
      /** @hide */
      public static final int AUDIOFOCUS_FLAGS_SYSTEM = AUDIOFOCUS_FLAG_DELAY_OK
              | AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS | AUDIOFOCUS_FLAG_LOCK;
  
      /**
       * Request audio focus.
       * See the {@link AudioFocusRequest} for information about the options available to configure
       * your request, and notification of focus gain and loss.
       * @param focusRequest a {@link AudioFocusRequest} instance used to configure how focus is
       *   requested.
       * @return {@link #AUDIOFOCUS_REQUEST_FAILED}, {@link #AUDIOFOCUS_REQUEST_GRANTED}
       *     or {@link #AUDIOFOCUS_REQUEST_DELAYED}.
       *     <br>Note that the return value is never {@link #AUDIOFOCUS_REQUEST_DELAYED} when focus
       *     is requested without building the {@link AudioFocusRequest} with
       *     {@link AudioFocusRequest.Builder#setAcceptsDelayedFocusGain(boolean)} set to
       *     {@code true}.
       * @throws NullPointerException if passed a null argument
       */
      public int requestAudioFocus(@NonNull AudioFocusRequest focusRequest) {
          return requestAudioFocus(focusRequest, null /* no AudioPolicy*/);
      }
  
      /**
       *  Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
       *  @param focusRequest the {@link AudioFocusRequest} that was used when requesting focus
       *      with {@link #requestAudioFocus(AudioFocusRequest)}.
       *  @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
       *  @throws IllegalArgumentException if passed a null argument
       */
      public int abandonAudioFocusRequest(@NonNull AudioFocusRequest focusRequest) {
          if (focusRequest == null) {
              throw new IllegalArgumentException("Illegal null AudioFocusRequest");
          }
          return abandonAudioFocus(focusRequest.getOnAudioFocusChangeListener(),
                  focusRequest.getAudioAttributes());
      }
  
      /**
       * @hide
       * Request audio focus.
       * Send a request to obtain the audio focus. This method differs from
       * {@link #requestAudioFocus(OnAudioFocusChangeListener, int, int)} in that it can express
       * that the requester accepts delayed grants of audio focus.
       * @param l the listener to be notified of audio focus changes. It is not allowed to be null
       *     when the request is flagged with {@link #AUDIOFOCUS_FLAG_DELAY_OK}.
       * @param requestAttributes non null {@link AudioAttributes} describing the main reason for
       *     requesting audio focus.
       * @param durationHint use {@link #AUDIOFOCUS_GAIN_TRANSIENT} to indicate this focus request
       *      is temporary, and focus will be abandonned shortly. Examples of transient requests are
       *      for the playback of driving directions, or notifications sounds.
       *      Use {@link #AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK} to indicate also that it's ok for
       *      the previous focus owner to keep playing if it ducks its audio output.
       *      Alternatively use {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE} for a temporary request
       *      that benefits from the system not playing disruptive sounds like notifications, for
       *      usecases such as voice memo recording, or speech recognition.
       *      Use {@link #AUDIOFOCUS_GAIN} for a focus request of unknown duration such
       *      as the playback of a song or a video.
       * @param flags 0 or a combination of {link #AUDIOFOCUS_FLAG_DELAY_OK},
       *     {@link #AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS} and {@link #AUDIOFOCUS_FLAG_LOCK}.
       *     <br>Use 0 when not using any flags for the request, which behaves like
       *     {@link #requestAudioFocus(OnAudioFocusChangeListener, int, int)}, where either audio
       *     focus is granted immediately, or the grant request fails because the system is in a
       *     state where focus cannot change (e.g. a phone call).
       * @return {@link #AUDIOFOCUS_REQUEST_FAILED}, {@link #AUDIOFOCUS_REQUEST_GRANTED}
       *     or {@link #AUDIOFOCUS_REQUEST_DELAYED}.
       *     The return value is never {@link #AUDIOFOCUS_REQUEST_DELAYED} when focus is requested
       *     without the {@link #AUDIOFOCUS_FLAG_DELAY_OK} flag.
       * @throws IllegalArgumentException
       */
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
      public int requestAudioFocus(OnAudioFocusChangeListener l,
              @NonNull AudioAttributes requestAttributes,
              int durationHint,
              int flags) throws IllegalArgumentException {
          if (flags != (flags & AUDIOFOCUS_FLAGS_APPS)) {
              throw new IllegalArgumentException("Invalid flags 0x"
                      + Integer.toHexString(flags).toUpperCase());
          }
          return requestAudioFocus(l, requestAttributes, durationHint,
                  flags & AUDIOFOCUS_FLAGS_APPS,
                  null /* no AudioPolicy*/);
      }
  
      /**
       * @hide
       * Request or lock audio focus.
       * This method is to be used by system components that have registered an
       * {@link android.media.audiopolicy.AudioPolicy} to request audio focus, but also to "lock" it
       * so focus granting is temporarily disabled.
       * @param l see the description of the same parameter in
       *     {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)}
       * @param requestAttributes non null {@link AudioAttributes} describing the main reason for
       *     requesting audio focus.
       * @param durationHint see the description of the same parameter in
       *     {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)}
       * @param flags 0 or a combination of {link #AUDIOFOCUS_FLAG_DELAY_OK},
       *     {@link #AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS}, and {@link #AUDIOFOCUS_FLAG_LOCK}.
       *     <br>Use 0 when not using any flags for the request, which behaves like
       *     {@link #requestAudioFocus(OnAudioFocusChangeListener, int, int)}, where either audio
       *     focus is granted immediately, or the grant request fails because the system is in a
       *     state where focus cannot change (e.g. a phone call).
       * @param ap a registered {@link android.media.audiopolicy.AudioPolicy} instance when locking
       *     focus, or null.
       * @return see the description of the same return value in
       *     {@link #requestAudioFocus(OnAudioFocusChangeListener, AudioAttributes, int, int)}
       * @throws IllegalArgumentException
       * @deprecated use {@link #requestAudioFocus(AudioFocusRequest, AudioPolicy)}
       */
      @SystemApi
      @RequiresPermission(anyOf= {
              android.Manifest.permission.MODIFY_PHONE_STATE,
              android.Manifest.permission.MODIFY_AUDIO_ROUTING
      })
      public int requestAudioFocus(OnAudioFocusChangeListener l,
              @NonNull AudioAttributes requestAttributes,
              int durationHint,
              int flags,
              AudioPolicy ap) throws IllegalArgumentException {
          // parameter checking
          if (requestAttributes == null) {
              throw new IllegalArgumentException("Illegal null AudioAttributes argument");
          }
          if (!AudioFocusRequest.isValidFocusGain(durationHint)) {
              throw new IllegalArgumentException("Invalid duration hint");
          }
          if (flags != (flags & AUDIOFOCUS_FLAGS_SYSTEM)) {
              throw new IllegalArgumentException("Illegal flags 0x"
                  + Integer.toHexString(flags).toUpperCase());
          }
          if (((flags & AUDIOFOCUS_FLAG_DELAY_OK) == AUDIOFOCUS_FLAG_DELAY_OK) && (l == null)) {
              throw new IllegalArgumentException(
                      "Illegal null focus listener when flagged as accepting delayed focus grant");
          }
          if (((flags & AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS)
                  == AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS) && (l == null)) {
              throw new IllegalArgumentException(
                      "Illegal null focus listener when flagged as pausing instead of ducking");
          }
          if (((flags & AUDIOFOCUS_FLAG_LOCK) == AUDIOFOCUS_FLAG_LOCK) && (ap == null)) {
              throw new IllegalArgumentException(
                      "Illegal null audio policy when locking audio focus");
          }
  
          final AudioFocusRequest afr = new AudioFocusRequest.Builder(durationHint)
                  .setOnAudioFocusChangeListenerInt(l, null /* no Handler for this legacy API */)
                  .setAudioAttributes(requestAttributes)
                  .setAcceptsDelayedFocusGain((flags & AUDIOFOCUS_FLAG_DELAY_OK)
                          == AUDIOFOCUS_FLAG_DELAY_OK)
                  .setWillPauseWhenDucked((flags & AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS)
                          == AUDIOFOCUS_FLAG_PAUSES_ON_DUCKABLE_LOSS)
                  .setLocksFocus((flags & AUDIOFOCUS_FLAG_LOCK) == AUDIOFOCUS_FLAG_LOCK)
                  .build();
          return requestAudioFocus(afr, ap);
      }
  
      /**
       * @hide
       * Request or lock audio focus.
       * This method is to be used by system components that have registered an
       * {@link android.media.audiopolicy.AudioPolicy} to request audio focus, but also to "lock" it
       * so focus granting is temporarily disabled.
       * @param afr see the description of the same parameter in
       *     {@link #requestAudioFocus(AudioFocusRequest)}
       * @param ap a registered {@link android.media.audiopolicy.AudioPolicy} instance when locking
       *     focus, or null.
       * @return {@link #AUDIOFOCUS_REQUEST_FAILED}, {@link #AUDIOFOCUS_REQUEST_GRANTED}
       *     or {@link #AUDIOFOCUS_REQUEST_DELAYED}.
       * @throws NullPointerException if the AudioFocusRequest is null
       * @throws IllegalArgumentException when trying to lock focus without an AudioPolicy
       */
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public int requestAudioFocus(@NonNull AudioFocusRequest afr, @Nullable AudioPolicy ap) {
          if (afr == null) {
              throw new NullPointerException("Illegal null AudioFocusRequest");
          }
          // this can only be checked now, not during the creation of the AudioFocusRequest instance
          if (afr.locksFocus() && ap == null) {
              throw new IllegalArgumentException(
                      "Illegal null audio policy when locking audio focus");
          }
          registerAudioFocusRequest(afr);
          final IAudioService service = getService();
          final int status;
          int sdk;
          try {
              sdk = getContext().getApplicationInfo().targetSdkVersion;
          } catch (NullPointerException e) {
              // some tests don't have a Context
              sdk = Build.VERSION.SDK_INT;
          }
  
          final String clientId = getIdForAudioFocusListener(afr.getOnAudioFocusChangeListener());
          final BlockingFocusResultReceiver focusReceiver;
          synchronized (mFocusRequestsLock) {
              try {
                  // TODO status contains result and generation counter for ext policy
                  status = service.requestAudioFocus(afr.getAudioAttributes(),
                          afr.getFocusGain(), mICallBack,
                          mAudioFocusDispatcher,
                          clientId,
                          getContext().getOpPackageName() /* package name */, afr.getFlags(),
                          ap != null ? ap.cb() : null,
                          sdk);
              } catch (RemoteException e) {
                  throw e.rethrowFromSystemServer();
              }
              if (status != AudioManager.AUDIOFOCUS_REQUEST_WAITING_FOR_EXT_POLICY) {
                  // default path with no external focus policy
                  return status;
              }
              if (mFocusRequestsAwaitingResult == null) {
                  mFocusRequestsAwaitingResult =
                          new HashMap<String, BlockingFocusResultReceiver>(1);
              }
              focusReceiver = new BlockingFocusResultReceiver(clientId);
              mFocusRequestsAwaitingResult.put(clientId, focusReceiver);
          }
          focusReceiver.waitForResult(EXT_FOCUS_POLICY_TIMEOUT_MS);
          if (DEBUG && !focusReceiver.receivedResult()) {
              Log.e(TAG, "requestAudio response from ext policy timed out, denying request");
          }
          synchronized (mFocusRequestsLock) {
              mFocusRequestsAwaitingResult.remove(clientId);
          }
          return focusReceiver.requestResult();
      }
  
      // helper class that abstracts out the handling of spurious wakeups in Object.wait()
      private static final class SafeWaitObject {
          private boolean mQuit = false;
  
          public void safeNotify() {
              synchronized (this) {
                  mQuit = true;
                  this.notify();
              }
          }
  
          public void safeWait(long millis) throws InterruptedException {
              final long timeOutTime = java.lang.System.currentTimeMillis() + millis;
              synchronized (this) {
                  while (!mQuit) {
                      final long timeToWait = timeOutTime - java.lang.System.currentTimeMillis();
                      if (timeToWait < 0) { break; }
                      this.wait(timeToWait);
                  }
              }
          }
      }
  
      private static final class BlockingFocusResultReceiver {
          private final SafeWaitObject mLock = new SafeWaitObject();
          @GuardedBy("mLock")
          private boolean mResultReceived = false;
          // request denied by default (e.g. timeout)
          private int mFocusRequestResult = AudioManager.AUDIOFOCUS_REQUEST_FAILED;
          private final String mFocusClientId;
  
          BlockingFocusResultReceiver(String clientId) {
              mFocusClientId = clientId;
          }
  
          boolean receivedResult() { return mResultReceived; }
          int requestResult() { return mFocusRequestResult; }
  
          void notifyResult(int requestResult) {
              synchronized (mLock) {
                  mResultReceived = true;
                  mFocusRequestResult = requestResult;
                  mLock.safeNotify();
              }
          }
  
          public void waitForResult(long timeOutMs) {
              synchronized (mLock) {
                  if (mResultReceived) {
                      // the result was received before waiting
                      return;
                  }
                  try {
                      mLock.safeWait(timeOutMs);
                  } catch (InterruptedException e) { }
              }
          }
      }
  
      /**
       * @hide
       * Used internally by telephony package to request audio focus. Will cause the focus request
       * to be associated with the "voice communication" identifier only used in AudioService
       * to identify this use case.
       * @param streamType use STREAM_RING for focus requests when ringing, VOICE_CALL for
       *    the establishment of the call
       * @param durationHint the type of focus request. AUDIOFOCUS_GAIN_TRANSIENT is recommended so
       *    media applications resume after a call
       */
      @UnsupportedAppUsage
      public void requestAudioFocusForCall(int streamType, int durationHint) {
          final IAudioService service = getService();
          try {
              service.requestAudioFocus(new AudioAttributes.Builder()
                          .setInternalLegacyStreamType(streamType).build(),
                      durationHint, mICallBack, null,
                      AudioSystem.IN_VOICE_COMM_FOCUS_ID,
                      getContext().getOpPackageName(),
                      AUDIOFOCUS_FLAG_LOCK,
                      null /* policy token */, 0 /* sdk n/a here*/);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Return the volume ramping time for a sound to be played after the given focus request,
       *   and to play a sound of the given attributes
       * @param focusGain
       * @param attr
       * @return
       */
      public int getFocusRampTimeMs(int focusGain, AudioAttributes attr) {
          final IAudioService service = getService();
          try {
              return service.getFocusRampTimeMs(focusGain, attr);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Set the result to the audio focus request received through
       * {@link AudioPolicyFocusListener#onAudioFocusRequest(AudioFocusInfo, int)}.
       * @param afi the information about the focus requester
       * @param requestResult the result to the focus request to be passed to the requester
       * @param ap a valid registered {@link AudioPolicy} configured as a focus policy.
       */
      @TestApi
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public void setFocusRequestResult(@NonNull AudioFocusInfo afi,
              @FocusRequestResult int requestResult, @NonNull AudioPolicy ap) {
          if (afi == null) {
              throw new IllegalArgumentException("Illegal null AudioFocusInfo");
          }
          if (ap == null) {
              throw new IllegalArgumentException("Illegal null AudioPolicy");
          }
          final IAudioService service = getService();
          try {
              service.setFocusRequestResultFromExtPolicy(afi, requestResult, ap.cb());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Notifies an application with a focus listener of gain or loss of audio focus.
       * This method can only be used by owners of an {@link AudioPolicy} configured with
       * {@link AudioPolicy.Builder#setIsAudioFocusPolicy(boolean)} set to true.
       * @param afi the recipient of the focus change, that has previously requested audio focus, and
       *     that was received by the {@code AudioPolicy} through
       *     {@link AudioPolicy.AudioPolicyFocusListener#onAudioFocusRequest(AudioFocusInfo, int)}.
       * @param focusChange one of focus gain types ({@link #AUDIOFOCUS_GAIN},
       *     {@link #AUDIOFOCUS_GAIN_TRANSIENT}, {@link #AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK} or
       *     {@link #AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE})
       *     or one of the focus loss types ({@link AudioManager#AUDIOFOCUS_LOSS},
       *     {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT},
       *     or {@link AudioManager#AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK}).
       *     <br>For the focus gain, the change type should be the same as the app requested.
       * @param ap a valid registered {@link AudioPolicy} configured as a focus policy.
       * @return {@link #AUDIOFOCUS_REQUEST_GRANTED} if the dispatch was successfully sent, or
       *     {@link #AUDIOFOCUS_REQUEST_FAILED} if the focus client didn't have a listener, or
       *     if there was an error sending the request.
       * @throws NullPointerException if the {@link AudioFocusInfo} or {@link AudioPolicy} are null.
       */
      @TestApi
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public int dispatchAudioFocusChange(@NonNull AudioFocusInfo afi, int focusChange,
              @NonNull AudioPolicy ap) {
          if (afi == null) {
              throw new NullPointerException("Illegal null AudioFocusInfo");
          }
          if (ap == null) {
              throw new NullPointerException("Illegal null AudioPolicy");
          }
          final IAudioService service = getService();
          try {
              return service.dispatchFocusChange(afi, focusChange, ap.cb());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Used internally by telephony package to abandon audio focus, typically after a call or
       * when ringing ends and the call is rejected or not answered.
       * Should match one or more calls to {@link #requestAudioFocusForCall(int, int)}.
       */
      @UnsupportedAppUsage
      public void abandonAudioFocusForCall() {
          final IAudioService service = getService();
          try {
              service.abandonAudioFocus(null, AudioSystem.IN_VOICE_COMM_FOCUS_ID,
                      null /*AudioAttributes, legacy behavior*/, getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       *  Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
       *  @param l the listener with which focus was requested.
       *  @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
       *  @deprecated use {@link #abandonAudioFocusRequest(AudioFocusRequest)}
       */
      public int abandonAudioFocus(OnAudioFocusChangeListener l) {
          return abandonAudioFocus(l, null /*AudioAttributes, legacy behavior*/);
      }
  
      /**
       * @hide
       * Abandon audio focus. Causes the previous focus owner, if any, to receive focus.
       *  @param l the listener with which focus was requested.
       * @param aa the {@link AudioAttributes} with which audio focus was requested
       * @return {@link #AUDIOFOCUS_REQUEST_FAILED} or {@link #AUDIOFOCUS_REQUEST_GRANTED}
       * @deprecated use {@link #abandonAudioFocusRequest(AudioFocusRequest)}
       */
      @SystemApi
      @SuppressLint("Doclava125") // no permission enforcement, but only "undoes" what would have been
                                  // done by a matching requestAudioFocus
      public int abandonAudioFocus(OnAudioFocusChangeListener l, AudioAttributes aa) {
          int status = AUDIOFOCUS_REQUEST_FAILED;
          unregisterAudioFocusRequest(l);
          final IAudioService service = getService();
          try {
              status = service.abandonAudioFocus(mAudioFocusDispatcher,
                      getIdForAudioFocusListener(l), aa, getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
          return status;
      }
  
      //====================================================================
      // Remote Control
      /**
       * Register a component to be the sole receiver of MEDIA_BUTTON intents.
       * @param eventReceiver identifier of a {@link android.content.BroadcastReceiver}
       *      that will receive the media button intent. This broadcast receiver must be declared
       *      in the application manifest. The package of the component must match that of
       *      the context you're registering from.
       * @deprecated Use {@link MediaSession#setMediaButtonReceiver(PendingIntent)} instead.
       */
      @Deprecated
      public void registerMediaButtonEventReceiver(ComponentName eventReceiver) {
          if (eventReceiver == null) {
              return;
          }
          if (!eventReceiver.getPackageName().equals(getContext().getPackageName())) {
              Log.e(TAG, "registerMediaButtonEventReceiver() error: " +
                      "receiver and context package names don't match");
              return;
          }
          // construct a PendingIntent for the media button and register it
          Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
          //     the associated intent will be handled by the component being registered
          mediaButtonIntent.setComponent(eventReceiver);
          PendingIntent pi = PendingIntent.getBroadcast(getContext(),
                  0/*requestCode, ignored*/, mediaButtonIntent, 0/*flags*/);
          registerMediaButtonIntent(pi, eventReceiver);
      }
  
      /**
       * Register a component to be the sole receiver of MEDIA_BUTTON intents.  This is like
       * {@link #registerMediaButtonEventReceiver(android.content.ComponentName)}, but allows
       * the buttons to go to any PendingIntent.  Note that you should only use this form if
       * you know you will continue running for the full time until unregistering the
       * PendingIntent.
       * @param eventReceiver target that will receive media button intents.  The PendingIntent
       * will be sent an {@link Intent#ACTION_MEDIA_BUTTON} event when a media button action
       * occurs, with {@link Intent#EXTRA_KEY_EVENT} added and holding the key code of the
       * media button that was pressed.
       * @deprecated Use {@link MediaSession#setMediaButtonReceiver(PendingIntent)} instead.
       */
      @Deprecated
      public void registerMediaButtonEventReceiver(PendingIntent eventReceiver) {
          if (eventReceiver == null) {
              return;
          }
          registerMediaButtonIntent(eventReceiver, null);
      }
  
      /**
       * @hide
       * no-op if (pi == null) or (eventReceiver == null)
       */
      public void registerMediaButtonIntent(PendingIntent pi, ComponentName eventReceiver) {
          if (pi == null) {
              Log.e(TAG, "Cannot call registerMediaButtonIntent() with a null parameter");
              return;
          }
          MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
          helper.addMediaButtonListener(pi, eventReceiver, getContext());
      }
  
      /**
       * Unregister the receiver of MEDIA_BUTTON intents.
       * @param eventReceiver identifier of a {@link android.content.BroadcastReceiver}
       *      that was registered with {@link #registerMediaButtonEventReceiver(ComponentName)}.
       * @deprecated Use {@link MediaSession} instead.
       */
      @Deprecated
      public void unregisterMediaButtonEventReceiver(ComponentName eventReceiver) {
          if (eventReceiver == null) {
              return;
          }
          // construct a PendingIntent for the media button and unregister it
          Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
          //     the associated intent will be handled by the component being registered
          mediaButtonIntent.setComponent(eventReceiver);
          PendingIntent pi = PendingIntent.getBroadcast(getContext(),
                  0/*requestCode, ignored*/, mediaButtonIntent, 0/*flags*/);
          unregisterMediaButtonIntent(pi);
      }
  
      /**
       * Unregister the receiver of MEDIA_BUTTON intents.
       * @param eventReceiver same PendingIntent that was registed with
       *      {@link #registerMediaButtonEventReceiver(PendingIntent)}.
       * @deprecated Use {@link MediaSession} instead.
       */
      @Deprecated
      public void unregisterMediaButtonEventReceiver(PendingIntent eventReceiver) {
          if (eventReceiver == null) {
              return;
          }
          unregisterMediaButtonIntent(eventReceiver);
      }
  
      /**
       * @hide
       */
      public void unregisterMediaButtonIntent(PendingIntent pi) {
          MediaSessionLegacyHelper helper = MediaSessionLegacyHelper.getHelper(getContext());
          helper.removeMediaButtonListener(pi);
      }
  
      /**
       * Registers the remote control client for providing information to display on the remote
       * controls.
       * @param rcClient The remote control client from which remote controls will receive
       *      information to display.
       * @see RemoteControlClient
       * @deprecated Use {@link MediaSession} instead.
       */
      @Deprecated
      public void registerRemoteControlClient(RemoteControlClient rcClient) {
          if ((rcClient == null) || (rcClient.getRcMediaIntent() == null)) {
              return;
          }
          rcClient.registerWithSession(MediaSessionLegacyHelper.getHelper(getContext()));
      }
  
      /**
       * Unregisters the remote control client that was providing information to display on the
       * remote controls.
       * @param rcClient The remote control client to unregister.
       * @see #registerRemoteControlClient(RemoteControlClient)
       * @deprecated Use {@link MediaSession} instead.
       */
      @Deprecated
      public void unregisterRemoteControlClient(RemoteControlClient rcClient) {
          if ((rcClient == null) || (rcClient.getRcMediaIntent() == null)) {
              return;
          }
          rcClient.unregisterWithSession(MediaSessionLegacyHelper.getHelper(getContext()));
      }
  
      /**
       * Registers a {@link RemoteController} instance for it to receive media
       * metadata updates and playback state information from applications using
       * {@link RemoteControlClient}, and control their playback.
       * <p>
       * Registration requires the {@link RemoteController.OnClientUpdateListener} listener to be
       * one of the enabled notification listeners (see
       * {@link android.service.notification.NotificationListenerService}).
       *
       * @param rctlr the object to register.
       * @return true if the {@link RemoteController} was successfully registered,
       *         false if an error occurred, due to an internal system error, or
       *         insufficient permissions.
       * @deprecated Use
       *             {@link MediaSessionManager#addOnActiveSessionsChangedListener(android.media.session.MediaSessionManager.OnActiveSessionsChangedListener, ComponentName)}
       *             and {@link MediaController} instead.
       */
      @Deprecated
      public boolean registerRemoteController(RemoteController rctlr) {
          if (rctlr == null) {
              return false;
          }
          rctlr.startListeningToSessions();
          return true;
      }
  
      /**
       * Unregisters a {@link RemoteController}, causing it to no longer receive
       * media metadata and playback state information, and no longer be capable
       * of controlling playback.
       *
       * @param rctlr the object to unregister.
       * @deprecated Use
       *             {@link MediaSessionManager#removeOnActiveSessionsChangedListener(android.media.session.MediaSessionManager.OnActiveSessionsChangedListener)}
       *             instead.
       */
      @Deprecated
      public void unregisterRemoteController(RemoteController rctlr) {
          if (rctlr == null) {
              return;
          }
          rctlr.stopListeningToSessions();
      }
  
  
      //====================================================================
      // Audio policy
      /**
       * @hide
       * Register the given {@link AudioPolicy}.
       * This call is synchronous and blocks until the registration process successfully completed
       * or failed to complete.
       * @param policy the non-null {@link AudioPolicy} to register.
       * @return {@link #ERROR} if there was an error communicating with the registration service
       *    or if the user doesn't have the required
       *    {@link android.Manifest.permission#MODIFY_AUDIO_ROUTING} permission,
       *    {@link #SUCCESS} otherwise.
       */
      @TestApi
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public int registerAudioPolicy(@NonNull AudioPolicy policy) {
          return registerAudioPolicyStatic(policy);
      }
  
      static int registerAudioPolicyStatic(@NonNull AudioPolicy policy) {
          if (policy == null) {
              throw new IllegalArgumentException("Illegal null AudioPolicy argument");
          }
          final IAudioService service = getService();
          try {
              MediaProjection projection = policy.getMediaProjection();
              String regId = service.registerAudioPolicy(policy.getConfig(), policy.cb(),
                      policy.hasFocusListener(), policy.isFocusPolicy(), policy.isTestFocusPolicy(),
                      policy.isVolumeController(),
                      projection == null ? null : projection.getProjection());
              if (regId == null) {
                  return ERROR;
              } else {
                  policy.setRegistration(regId);
              }
              // successful registration
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
          return SUCCESS;
      }
  
      /**
       * @hide
       * Unregisters an {@link AudioPolicy} asynchronously.
       * @param policy the non-null {@link AudioPolicy} to unregister.
       */
      @TestApi
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public void unregisterAudioPolicyAsync(@NonNull AudioPolicy policy) {
          unregisterAudioPolicyAsyncStatic(policy);
      }
  
      static void unregisterAudioPolicyAsyncStatic(@NonNull AudioPolicy policy) {
          if (policy == null) {
              throw new IllegalArgumentException("Illegal null AudioPolicy argument");
          }
          final IAudioService service = getService();
          try {
              service.unregisterAudioPolicyAsync(policy.cb());
              policy.setRegistration(null);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Unregisters an {@link AudioPolicy} synchronously.
       * This method also invalidates all {@link AudioRecord} and {@link AudioTrack} objects
       * associated with mixes of this policy.
       * @param policy the non-null {@link AudioPolicy} to unregister.
       */
      @TestApi
      @SystemApi
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public void unregisterAudioPolicy(@NonNull AudioPolicy policy) {
          Preconditions.checkNotNull(policy, "Illegal null AudioPolicy argument");
          final IAudioService service = getService();
          try {
              policy.invalidateCaptorsAndInjectors();
              service.unregisterAudioPolicy(policy.cb());
              policy.setRegistration(null);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * @return true if an AudioPolicy was previously registered
       */
      @TestApi
      public boolean hasRegisteredDynamicPolicy() {
          final IAudioService service = getService();
          try {
              return service.hasRegisteredDynamicPolicy();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      //====================================================================
      // Notification of playback activity & playback configuration
      /**
       * Interface for receiving update notifications about the playback activity on the system.
       * Extend this abstract class and register it with
       * {@link AudioManager#registerAudioPlaybackCallback(AudioPlaybackCallback, Handler)}
       * to be notified.
       * Use {@link AudioManager#getActivePlaybackConfigurations()} to query the current
       * configuration.
       * @see AudioPlaybackConfiguration
       */
      public static abstract class AudioPlaybackCallback {
          /**
           * Called whenever the playback activity and configuration has changed.
           * @param configs list containing the results of
           *      {@link AudioManager#getActivePlaybackConfigurations()}.
           */
          public void onPlaybackConfigChanged(List<AudioPlaybackConfiguration> configs) {}
      }
  
      private static class AudioPlaybackCallbackInfo {
          final AudioPlaybackCallback mCb;
          final Handler mHandler;
          AudioPlaybackCallbackInfo(AudioPlaybackCallback cb, Handler handler) {
              mCb = cb;
              mHandler = handler;
          }
      }
  
      private final static class PlaybackConfigChangeCallbackData {
          final AudioPlaybackCallback mCb;
          final List<AudioPlaybackConfiguration> mConfigs;
  
          PlaybackConfigChangeCallbackData(AudioPlaybackCallback cb,
                  List<AudioPlaybackConfiguration> configs) {
              mCb = cb;
              mConfigs = configs;
          }
      }
  
      /**
       * Register a callback to be notified of audio playback changes through
       * {@link AudioPlaybackCallback}
       * @param cb non-null callback to register
       * @param handler the {@link Handler} object for the thread on which to execute
       * the callback. If <code>null</code>, the {@link Handler} associated with the main
       * {@link Looper} will be used.
       */
      public void registerAudioPlaybackCallback(@NonNull AudioPlaybackCallback cb, Handler handler)
      {
          if (cb == null) {
              throw new IllegalArgumentException("Illegal null AudioPlaybackCallback argument");
          }
  
          synchronized(mPlaybackCallbackLock) {
              // lazy initialization of the list of playback callbacks
              if (mPlaybackCallbackList == null) {
                  mPlaybackCallbackList = new ArrayList<AudioPlaybackCallbackInfo>();
              }
              final int oldCbCount = mPlaybackCallbackList.size();
              if (!hasPlaybackCallback_sync(cb)) {
                  mPlaybackCallbackList.add(new AudioPlaybackCallbackInfo(cb,
                          new ServiceEventHandlerDelegate(handler).getHandler()));
                  final int newCbCount = mPlaybackCallbackList.size();
                  if ((oldCbCount == 0) && (newCbCount > 0)) {
                      // register binder for callbacks
                      try {
                          getService().registerPlaybackCallback(mPlayCb);
                      } catch (RemoteException e) {
                          throw e.rethrowFromSystemServer();
                      }
                  }
              } else {
                  Log.w(TAG, "attempt to call registerAudioPlaybackCallback() on a previously"
                          + "registered callback");
              }
          }
      }
  
      /**
       * Unregister an audio playback callback previously registered with
       * {@link #registerAudioPlaybackCallback(AudioPlaybackCallback, Handler)}.
       * @param cb non-null callback to unregister
       */
      public void unregisterAudioPlaybackCallback(@NonNull AudioPlaybackCallback cb) {
          if (cb == null) {
              throw new IllegalArgumentException("Illegal null AudioPlaybackCallback argument");
          }
          synchronized(mPlaybackCallbackLock) {
              if (mPlaybackCallbackList == null) {
                  Log.w(TAG, "attempt to call unregisterAudioPlaybackCallback() on a callback"
                          + " that was never registered");
                  return;
              }
              final int oldCbCount = mPlaybackCallbackList.size();
              if (removePlaybackCallback_sync(cb)) {
                  final int newCbCount = mPlaybackCallbackList.size();
                  if ((oldCbCount > 0) && (newCbCount == 0)) {
                      // unregister binder for callbacks
                      try {
                          getService().unregisterPlaybackCallback(mPlayCb);
                      } catch (RemoteException e) {
                          throw e.rethrowFromSystemServer();
                      }
                  }
              } else {
                  Log.w(TAG, "attempt to call unregisterAudioPlaybackCallback() on a callback"
                          + " already unregistered or never registered");
              }
          }
      }
  
      /**
       * Returns the current active audio playback configurations of the device
       * @return a non-null list of playback configurations. An empty list indicates there is no
       *     playback active when queried.
       * @see AudioPlaybackConfiguration
       */
      public @NonNull List<AudioPlaybackConfiguration> getActivePlaybackConfigurations() {
          final IAudioService service = getService();
          try {
              return service.getActivePlaybackConfigurations();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * All operations on this list are sync'd on mPlaybackCallbackLock.
       * List is lazy-initialized in
       * {@link #registerAudioPlaybackCallback(AudioPlaybackCallback, Handler)}.
       * List can be null.
       */
      private List<AudioPlaybackCallbackInfo> mPlaybackCallbackList;
      private final Object mPlaybackCallbackLock = new Object();
  
      /**
       * Must be called synchronized on mPlaybackCallbackLock
       */
      private boolean hasPlaybackCallback_sync(@NonNull AudioPlaybackCallback cb) {
          if (mPlaybackCallbackList != null) {
              for (int i=0 ; i < mPlaybackCallbackList.size() ; i++) {
                  if (cb.equals(mPlaybackCallbackList.get(i).mCb)) {
                      return true;
                  }
              }
          }
          return false;
      }
  
      /**
       * Must be called synchronized on mPlaybackCallbackLock
       */
      private boolean removePlaybackCallback_sync(@NonNull AudioPlaybackCallback cb) {
          if (mPlaybackCallbackList != null) {
              for (int i=0 ; i < mPlaybackCallbackList.size() ; i++) {
                  if (cb.equals(mPlaybackCallbackList.get(i).mCb)) {
                      mPlaybackCallbackList.remove(i);
                      return true;
                  }
              }
          }
          return false;
      }
  
      private final IPlaybackConfigDispatcher mPlayCb = new IPlaybackConfigDispatcher.Stub() {
          @Override
          public void dispatchPlaybackConfigChange(List<AudioPlaybackConfiguration> configs,
                  boolean flush) {
              if (flush) {
                  Binder.flushPendingCommands();
              }
              synchronized(mPlaybackCallbackLock) {
                  if (mPlaybackCallbackList != null) {
                      for (int i=0 ; i < mPlaybackCallbackList.size() ; i++) {
                          final AudioPlaybackCallbackInfo arci = mPlaybackCallbackList.get(i);
                          if (arci.mHandler != null) {
                              final Message m = arci.mHandler.obtainMessage(
                                      MSSG_PLAYBACK_CONFIG_CHANGE/*what*/,
                                      new PlaybackConfigChangeCallbackData(arci.mCb, configs)/*obj*/);
                              arci.mHandler.sendMessage(m);
                          }
                      }
                  }
              }
          }
  
      };
  
      //====================================================================
      // Notification of recording activity & recording configuration
      /**
       * Interface for receiving update notifications about the recording configuration. Extend
       * this abstract class and register it with
       * {@link AudioManager#registerAudioRecordingCallback(AudioRecordingCallback, Handler)}
       * to be notified.
       * Use {@link AudioManager#getActiveRecordingConfigurations()} to query the current
       * configuration.
       * @see AudioRecordingConfiguration
       */
      public static abstract class AudioRecordingCallback {
          /**
           * Called whenever the device recording configuration has changed.
           * @param configs list containing the results of
           *      {@link AudioManager#getActiveRecordingConfigurations()}.
           */
          public void onRecordingConfigChanged(List<AudioRecordingConfiguration> configs) {}
      }
  
      private static class AudioRecordingCallbackInfo {
          final AudioRecordingCallback mCb;
          final Handler mHandler;
          AudioRecordingCallbackInfo(AudioRecordingCallback cb, Handler handler) {
              mCb = cb;
              mHandler = handler;
          }
      }
  
      private final static class RecordConfigChangeCallbackData {
          final AudioRecordingCallback mCb;
          final List<AudioRecordingConfiguration> mConfigs;
  
          RecordConfigChangeCallbackData(AudioRecordingCallback cb,
                  List<AudioRecordingConfiguration> configs) {
              mCb = cb;
              mConfigs = configs;
          }
      }
  
      /**
       * Register a callback to be notified of audio recording changes through
       * {@link AudioRecordingCallback}
       * @param cb non-null callback to register
       * @param handler the {@link Handler} object for the thread on which to execute
       * the callback. If <code>null</code>, the {@link Handler} associated with the main
       * {@link Looper} will be used.
       */
      public void registerAudioRecordingCallback(@NonNull AudioRecordingCallback cb, Handler handler)
      {
          if (cb == null) {
              throw new IllegalArgumentException("Illegal null AudioRecordingCallback argument");
          }
  
          synchronized(mRecordCallbackLock) {
              // lazy initialization of the list of recording callbacks
              if (mRecordCallbackList == null) {
                  mRecordCallbackList = new ArrayList<AudioRecordingCallbackInfo>();
              }
              final int oldCbCount = mRecordCallbackList.size();
              if (!hasRecordCallback_sync(cb)) {
                  mRecordCallbackList.add(new AudioRecordingCallbackInfo(cb,
                          new ServiceEventHandlerDelegate(handler).getHandler()));
                  final int newCbCount = mRecordCallbackList.size();
                  if ((oldCbCount == 0) && (newCbCount > 0)) {
                      // register binder for callbacks
                      final IAudioService service = getService();
                      try {
                          service.registerRecordingCallback(mRecCb);
                      } catch (RemoteException e) {
                          throw e.rethrowFromSystemServer();
                      }
                  }
              } else {
                  Log.w(TAG, "attempt to call registerAudioRecordingCallback() on a previously"
                          + "registered callback");
              }
          }
      }
  
      /**
       * Unregister an audio recording callback previously registered with
       * {@link #registerAudioRecordingCallback(AudioRecordingCallback, Handler)}.
       * @param cb non-null callback to unregister
       */
      public void unregisterAudioRecordingCallback(@NonNull AudioRecordingCallback cb) {
          if (cb == null) {
              throw new IllegalArgumentException("Illegal null AudioRecordingCallback argument");
          }
          synchronized(mRecordCallbackLock) {
              if (mRecordCallbackList == null) {
                  return;
              }
              final int oldCbCount = mRecordCallbackList.size();
              if (removeRecordCallback_sync(cb)) {
                  final int newCbCount = mRecordCallbackList.size();
                  if ((oldCbCount > 0) && (newCbCount == 0)) {
                      // unregister binder for callbacks
                      final IAudioService service = getService();
                      try {
                          service.unregisterRecordingCallback(mRecCb);
                      } catch (RemoteException e) {
                          throw e.rethrowFromSystemServer();
                      }
                  }
              } else {
                  Log.w(TAG, "attempt to call unregisterAudioRecordingCallback() on a callback"
                          + " already unregistered or never registered");
              }
          }
      }
  
      /**
       * Returns the current active audio recording configurations of the device.
       * @return a non-null list of recording configurations. An empty list indicates there is
       *     no recording active when queried.
       * @see AudioRecordingConfiguration
       */
      public @NonNull List<AudioRecordingConfiguration> getActiveRecordingConfigurations() {
          final IAudioService service = getService();
          try {
              return service.getActiveRecordingConfigurations();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * constants for the recording events, to keep in sync
       * with frameworks/av/include/media/AudioPolicy.h
       */
      /** @hide */
      public static final int RECORD_CONFIG_EVENT_NONE = -1;
      /** @hide */
      public static final int RECORD_CONFIG_EVENT_START = 0;
      /** @hide */
      public static final int RECORD_CONFIG_EVENT_STOP = 1;
      /** @hide */
      public static final int RECORD_CONFIG_EVENT_UPDATE = 2;
      /** @hide */
      public static final int RECORD_CONFIG_EVENT_RELEASE = 3;
      /**
       * keep in sync with frameworks/native/include/audiomanager/AudioManager.h
       */
      /** @hide */
      public static final int RECORD_RIID_INVALID = -1;
      /** @hide */
      public static final int RECORDER_STATE_STARTED = 0;
      /** @hide */
      public static final int RECORDER_STATE_STOPPED = 1;
  
      /**
       * All operations on this list are sync'd on mRecordCallbackLock.
       * List is lazy-initialized in
       * {@link #registerAudioRecordingCallback(AudioRecordingCallback, Handler)}.
       * List can be null.
       */
      private List<AudioRecordingCallbackInfo> mRecordCallbackList;
      private final Object mRecordCallbackLock = new Object();
  
      /**
       * Must be called synchronized on mRecordCallbackLock
       */
      private boolean hasRecordCallback_sync(@NonNull AudioRecordingCallback cb) {
          if (mRecordCallbackList != null) {
              for (int i=0 ; i < mRecordCallbackList.size() ; i++) {
                  if (cb.equals(mRecordCallbackList.get(i).mCb)) {
                      return true;
                  }
              }
          }
          return false;
      }
  
      /**
       * Must be called synchronized on mRecordCallbackLock
       */
      private boolean removeRecordCallback_sync(@NonNull AudioRecordingCallback cb) {
          if (mRecordCallbackList != null) {
              for (int i=0 ; i < mRecordCallbackList.size() ; i++) {
                  if (cb.equals(mRecordCallbackList.get(i).mCb)) {
                      mRecordCallbackList.remove(i);
                      return true;
                  }
              }
          }
          return false;
      }
  
      private final IRecordingConfigDispatcher mRecCb = new IRecordingConfigDispatcher.Stub() {
          @Override
          public void dispatchRecordingConfigChange(List<AudioRecordingConfiguration> configs) {
              synchronized(mRecordCallbackLock) {
                  if (mRecordCallbackList != null) {
                      for (int i=0 ; i < mRecordCallbackList.size() ; i++) {
                          final AudioRecordingCallbackInfo arci = mRecordCallbackList.get(i);
                          if (arci.mHandler != null) {
                              final Message m = arci.mHandler.obtainMessage(
                                      MSSG_RECORDING_CONFIG_CHANGE/*what*/,
                                      new RecordConfigChangeCallbackData(arci.mCb, configs)/*obj*/);
                              arci.mHandler.sendMessage(m);
                          }
                      }
                  }
              }
          }
  
      };
  
      //=====================================================================
  
      /**
       *  @hide
       *  Reload audio settings. This method is called by Settings backup
       *  agent when audio settings are restored and causes the AudioService
       *  to read and apply restored settings.
       */
      @UnsupportedAppUsage
      public void reloadAudioSettings() {
          final IAudioService service = getService();
          try {
              service.reloadAudioSettings();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Notifies AudioService that it is connected to an A2DP device that supports absolute volume,
       * so that AudioService can send volume change events to the A2DP device, rather than handling
       * them.
       */
      public void avrcpSupportsAbsoluteVolume(String address, boolean support) {
          final IAudioService service = getService();
          try {
              service.avrcpSupportsAbsoluteVolume(address, support);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
       /**
        * {@hide}
        */
       private final IBinder mICallBack = new Binder();
  
      /**
       * Checks whether the phone is in silent mode, with or without vibrate.
       *
       * @return true if phone is in silent mode, with or without vibrate.
       *
       * @see #getRingerMode()
       *
       * @hide pending API Council approval
       */
      @UnsupportedAppUsage
      public boolean isSilentMode() {
          int ringerMode = getRingerMode();
          boolean silentMode =
              (ringerMode == RINGER_MODE_SILENT) ||
              (ringerMode == RINGER_MODE_VIBRATE);
          return silentMode;
      }
  
      // This section re-defines new output device constants from AudioSystem, because the AudioSystem
      // class is not used by other parts of the framework, which instead use definitions and methods
      // from AudioManager. AudioSystem is an internal class used by AudioManager and AudioService.
  
      /** @hide
       * The audio device code for representing "no device." */
      public static final int DEVICE_NONE = AudioSystem.DEVICE_NONE;
      /** @hide
       *  The audio output device code for the small speaker at the front of the device used
       *  when placing calls.  Does not refer to an in-ear headphone without attached microphone,
       *  such as earbuds, earphones, or in-ear monitors (IEM). Those would be handled as a
       *  {@link #DEVICE_OUT_WIRED_HEADPHONE}.
       */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_EARPIECE = AudioSystem.DEVICE_OUT_EARPIECE;
      /** @hide
       *  The audio output device code for the built-in speaker */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_SPEAKER = AudioSystem.DEVICE_OUT_SPEAKER;
      /** @hide
       * The audio output device code for a wired headset with attached microphone */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_WIRED_HEADSET = AudioSystem.DEVICE_OUT_WIRED_HEADSET;
      /** @hide
       * The audio output device code for a wired headphone without attached microphone */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_WIRED_HEADPHONE = AudioSystem.DEVICE_OUT_WIRED_HEADPHONE;
      /** @hide
       * The audio output device code for a USB headphone with attached microphone */
      public static final int DEVICE_OUT_USB_HEADSET = AudioSystem.DEVICE_OUT_USB_HEADSET;
      /** @hide
       * The audio output device code for generic Bluetooth SCO, for voice */
      public static final int DEVICE_OUT_BLUETOOTH_SCO = AudioSystem.DEVICE_OUT_BLUETOOTH_SCO;
      /** @hide
       * The audio output device code for Bluetooth SCO Headset Profile (HSP) and
       * Hands-Free Profile (HFP), for voice
       */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_BLUETOOTH_SCO_HEADSET =
              AudioSystem.DEVICE_OUT_BLUETOOTH_SCO_HEADSET;
      /** @hide
       * The audio output device code for Bluetooth SCO car audio, for voice */
      public static final int DEVICE_OUT_BLUETOOTH_SCO_CARKIT =
              AudioSystem.DEVICE_OUT_BLUETOOTH_SCO_CARKIT;
      /** @hide
       * The audio output device code for generic Bluetooth A2DP, for music */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_BLUETOOTH_A2DP = AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP;
      /** @hide
       * The audio output device code for Bluetooth A2DP headphones, for music */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES =
              AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES;
      /** @hide
       * The audio output device code for Bluetooth A2DP external speaker, for music */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER =
              AudioSystem.DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER;
      /** @hide
       * The audio output device code for S/PDIF (legacy) or HDMI
       * Deprecated: replaced by {@link #DEVICE_OUT_HDMI} */
      public static final int DEVICE_OUT_AUX_DIGITAL = AudioSystem.DEVICE_OUT_AUX_DIGITAL;
      /** @hide
       * The audio output device code for HDMI */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_HDMI = AudioSystem.DEVICE_OUT_HDMI;
      /** @hide
       * The audio output device code for an analog wired headset attached via a
       *  docking station
       */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_ANLG_DOCK_HEADSET = AudioSystem.DEVICE_OUT_ANLG_DOCK_HEADSET;
      /** @hide
       * The audio output device code for a digital wired headset attached via a
       *  docking station
       */
      @UnsupportedAppUsage
      public static final int DEVICE_OUT_DGTL_DOCK_HEADSET = AudioSystem.DEVICE_OUT_DGTL_DOCK_HEADSET;
      /** @hide
       * The audio output device code for a USB audio accessory. The accessory is in USB host
       * mode and the Android device in USB device mode
       */
      public static final int DEVICE_OUT_USB_ACCESSORY = AudioSystem.DEVICE_OUT_USB_ACCESSORY;
      /** @hide
       * The audio output device code for a USB audio device. The device is in USB device
       * mode and the Android device in USB host mode
       */
      public static final int DEVICE_OUT_USB_DEVICE = AudioSystem.DEVICE_OUT_USB_DEVICE;
      /** @hide
       * The audio output device code for projection output.
       */
      public static final int DEVICE_OUT_REMOTE_SUBMIX = AudioSystem.DEVICE_OUT_REMOTE_SUBMIX;
      /** @hide
       * The audio output device code the telephony voice TX path.
       */
      public static final int DEVICE_OUT_TELEPHONY_TX = AudioSystem.DEVICE_OUT_TELEPHONY_TX;
      /** @hide
       * The audio output device code for an analog jack with line impedance detected.
       */
      public static final int DEVICE_OUT_LINE = AudioSystem.DEVICE_OUT_LINE;
      /** @hide
       * The audio output device code for HDMI Audio Return Channel.
       */
      public static final int DEVICE_OUT_HDMI_ARC = AudioSystem.DEVICE_OUT_HDMI_ARC;
      /** @hide
       * The audio output device code for S/PDIF digital connection.
       */
      public static final int DEVICE_OUT_SPDIF = AudioSystem.DEVICE_OUT_SPDIF;
      /** @hide
       * The audio output device code for built-in FM transmitter.
       */
      public static final int DEVICE_OUT_FM = AudioSystem.DEVICE_OUT_FM;
      /** @hide
       * This is not used as a returned value from {@link #getDevicesForStream}, but could be
       *  used in the future in a set method to select whatever default device is chosen by the
       *  platform-specific implementation.
       */
      public static final int DEVICE_OUT_DEFAULT = AudioSystem.DEVICE_OUT_DEFAULT;
  
      /** @hide
       * The audio input device code for default built-in microphone
       */
      public static final int DEVICE_IN_BUILTIN_MIC = AudioSystem.DEVICE_IN_BUILTIN_MIC;
      /** @hide
       * The audio input device code for a Bluetooth SCO headset
       */
      public static final int DEVICE_IN_BLUETOOTH_SCO_HEADSET =
                                      AudioSystem.DEVICE_IN_BLUETOOTH_SCO_HEADSET;
      /** @hide
       * The audio input device code for wired headset microphone
       */
      public static final int DEVICE_IN_WIRED_HEADSET =
                                      AudioSystem.DEVICE_IN_WIRED_HEADSET;
      /** @hide
       * The audio input device code for HDMI
       */
      public static final int DEVICE_IN_HDMI =
                                      AudioSystem.DEVICE_IN_HDMI;
      /** @hide
       * The audio input device code for HDMI ARC
       */
      public static final int DEVICE_IN_HDMI_ARC =
                                      AudioSystem.DEVICE_IN_HDMI_ARC;
  
      /** @hide
       * The audio input device code for telephony voice RX path
       */
      public static final int DEVICE_IN_TELEPHONY_RX =
                                      AudioSystem.DEVICE_IN_TELEPHONY_RX;
      /** @hide
       * The audio input device code for built-in microphone pointing to the back
       */
      public static final int DEVICE_IN_BACK_MIC =
                                      AudioSystem.DEVICE_IN_BACK_MIC;
      /** @hide
       * The audio input device code for analog from a docking station
       */
      public static final int DEVICE_IN_ANLG_DOCK_HEADSET =
                                      AudioSystem.DEVICE_IN_ANLG_DOCK_HEADSET;
      /** @hide
       * The audio input device code for digital from a docking station
       */
      public static final int DEVICE_IN_DGTL_DOCK_HEADSET =
                                      AudioSystem.DEVICE_IN_DGTL_DOCK_HEADSET;
      /** @hide
       * The audio input device code for a USB audio accessory. The accessory is in USB host
       * mode and the Android device in USB device mode
       */
      public static final int DEVICE_IN_USB_ACCESSORY =
                                      AudioSystem.DEVICE_IN_USB_ACCESSORY;
      /** @hide
       * The audio input device code for a USB audio device. The device is in USB device
       * mode and the Android device in USB host mode
       */
      public static final int DEVICE_IN_USB_DEVICE =
                                      AudioSystem.DEVICE_IN_USB_DEVICE;
      /** @hide
       * The audio input device code for a FM radio tuner
       */
      public static final int DEVICE_IN_FM_TUNER = AudioSystem.DEVICE_IN_FM_TUNER;
      /** @hide
       * The audio input device code for a TV tuner
       */
      public static final int DEVICE_IN_TV_TUNER = AudioSystem.DEVICE_IN_TV_TUNER;
      /** @hide
       * The audio input device code for an analog jack with line impedance detected
       */
      public static final int DEVICE_IN_LINE = AudioSystem.DEVICE_IN_LINE;
      /** @hide
       * The audio input device code for a S/PDIF digital connection
       */
      public static final int DEVICE_IN_SPDIF = AudioSystem.DEVICE_IN_SPDIF;
      /** @hide
       * The audio input device code for audio loopback
       */
      public static final int DEVICE_IN_LOOPBACK = AudioSystem.DEVICE_IN_LOOPBACK;
  
      /**
       * Return true if the device code corresponds to an output device.
       * @hide
       */
      public static boolean isOutputDevice(int device)
      {
          return (device & AudioSystem.DEVICE_BIT_IN) == 0;
      }
  
      /**
       * Return true if the device code corresponds to an input device.
       * @hide
       */
      public static boolean isInputDevice(int device)
      {
          return (device & AudioSystem.DEVICE_BIT_IN) == AudioSystem.DEVICE_BIT_IN;
      }
  
  
      /**
       * Return the enabled devices for the specified output stream type.
       *
       * @param streamType The stream type to query. One of
       *            {@link #STREAM_VOICE_CALL},
       *            {@link #STREAM_SYSTEM},
       *            {@link #STREAM_RING},
       *            {@link #STREAM_MUSIC},
       *            {@link #STREAM_ALARM},
       *            {@link #STREAM_NOTIFICATION},
       *            {@link #STREAM_DTMF},
       *            {@link #STREAM_ACCESSIBILITY}.
       *
       * @return The bit-mask "or" of audio output device codes for all enabled devices on this
       *         stream. Zero or more of
       *            {@link #DEVICE_OUT_EARPIECE},
       *            {@link #DEVICE_OUT_SPEAKER},
       *            {@link #DEVICE_OUT_WIRED_HEADSET},
       *            {@link #DEVICE_OUT_WIRED_HEADPHONE},
       *            {@link #DEVICE_OUT_BLUETOOTH_SCO},
       *            {@link #DEVICE_OUT_BLUETOOTH_SCO_HEADSET},
       *            {@link #DEVICE_OUT_BLUETOOTH_SCO_CARKIT},
       *            {@link #DEVICE_OUT_BLUETOOTH_A2DP},
       *            {@link #DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES},
       *            {@link #DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER},
       *            {@link #DEVICE_OUT_HDMI},
       *            {@link #DEVICE_OUT_ANLG_DOCK_HEADSET},
       *            {@link #DEVICE_OUT_DGTL_DOCK_HEADSET}.
       *            {@link #DEVICE_OUT_USB_ACCESSORY}.
       *            {@link #DEVICE_OUT_USB_DEVICE}.
       *            {@link #DEVICE_OUT_REMOTE_SUBMIX}.
       *            {@link #DEVICE_OUT_TELEPHONY_TX}.
       *            {@link #DEVICE_OUT_LINE}.
       *            {@link #DEVICE_OUT_HDMI_ARC}.
       *            {@link #DEVICE_OUT_SPDIF}.
       *            {@link #DEVICE_OUT_FM}.
       *            {@link #DEVICE_OUT_DEFAULT} is not used here.
       *
       * The implementation may support additional device codes beyond those listed, so
       * the application should ignore any bits which it does not recognize.
       * Note that the information may be imprecise when the implementation
       * cannot distinguish whether a particular device is enabled.
       *
       * {@hide}
       */
      @UnsupportedAppUsage
      public int getDevicesForStream(int streamType) {
          switch (streamType) {
          case STREAM_VOICE_CALL:
          case STREAM_SYSTEM:
          case STREAM_RING:
          case STREAM_MUSIC:
          case STREAM_ALARM:
          case STREAM_NOTIFICATION:
          case STREAM_DTMF:
          case STREAM_ACCESSIBILITY:
              return AudioSystem.getDevicesForStream(streamType);
          default:
              return 0;
          }
      }
  
       /**
       * Indicate wired accessory connection state change.
       * @param device type of device connected/disconnected (AudioManager.DEVICE_OUT_xxx)
       * @param state  new connection state: 1 connected, 0 disconnected
       * @param name   device name
       * {@hide}
       */
      @UnsupportedAppUsage
      public void setWiredDeviceConnectionState(int type, int state, String address, String name) {
          final IAudioService service = getService();
          try {
              service.setWiredDeviceConnectionState(type, state, address, name,
                      mApplicationContext.getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
       /**
       * Indicate Hearing Aid connection state change and eventually suppress
       * the {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent.
       * This operation is asynchronous but its execution will still be sequentially scheduled
       * relative to calls to {@link #setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(
       * * BluetoothDevice, int, int, boolean, int)} and
       * and {@link #handleBluetoothA2dpDeviceConfigChange(BluetoothDevice)}.
       * @param device Bluetooth device connected/disconnected
       * @param state new connection state (BluetoothProfile.STATE_xxx)
       * @param musicDevice Default get system volume for the connecting device.
       * (either {@link android.bluetooth.BluetoothProfile.hearingaid} or
       * {@link android.bluetooth.BluetoothProfile.HEARING_AID})
       * @param suppressNoisyIntent if true the
       * {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent will not be sent.
       * {@hide}
       */
      public void setBluetoothHearingAidDeviceConnectionState(
                  BluetoothDevice device, int state, boolean suppressNoisyIntent,
                  int musicDevice) {
          final IAudioService service = getService();
          try {
              service.setBluetoothHearingAidDeviceConnectionState(device,
                  state, suppressNoisyIntent, musicDevice);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
       /**
       * Indicate A2DP source or sink connection state change and eventually suppress
       * the {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent.
       * This operation is asynchronous but its execution will still be sequentially scheduled
       * relative to calls to {@link #setBluetoothHearingAidDeviceConnectionState(BluetoothDevice,
       * int, boolean, int)} and
       * {@link #handleBluetoothA2dpDeviceConfigChange(BluetoothDevice)}.
       * @param device Bluetooth device connected/disconnected
       * @param state  new connection state, {@link BluetoothProfile#STATE_CONNECTED}
       *     or {@link BluetoothProfile#STATE_DISCONNECTED}
       * @param profile profile for the A2DP device
       * @param a2dpVolume New volume for the connecting device. Does nothing if disconnecting.
       * (either {@link android.bluetooth.BluetoothProfile.A2DP} or
       * {@link android.bluetooth.BluetoothProfile.A2DP_SINK})
       * @param suppressNoisyIntent if true the
       * {@link AudioManager.ACTION_AUDIO_BECOMING_NOISY} intent will not be sent.
       * {@hide}
       */
      public void setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(
              BluetoothDevice device, int state,
              int profile, boolean suppressNoisyIntent, int a2dpVolume) {
          final IAudioService service = getService();
          try {
              service.setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(device,
                  state, profile, suppressNoisyIntent, a2dpVolume);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
       /**
       * Indicate A2DP device configuration has changed.
       * This operation is asynchronous but its execution will still be sequentially scheduled
       * relative to calls to
       * {@link #setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(BluetoothDevice, int, int,
       * boolean, int)} and
       * {@link #setBluetoothHearingAidDeviceConnectionState(BluetoothDevice, int, boolean, int)}
       * @param device Bluetooth device whose configuration has changed.
       * {@hide}
       */
      public void handleBluetoothA2dpDeviceConfigChange(BluetoothDevice device) {
          final IAudioService service = getService();
          try {
              service.handleBluetoothA2dpDeviceConfigChange(device);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /** {@hide} */
      public IRingtonePlayer getRingtonePlayer() {
          try {
              return getService().getRingtonePlayer();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Used as a key for {@link #getProperty} to request the native or optimal output sample rate
       * for this device's low latency output stream, in decimal Hz.  Latency-sensitive apps
       * should use this value as a default, and offer the user the option to override it.
       * The low latency output stream is typically either the device's primary output stream,
       * or another output stream with smaller buffers.
       */
      // FIXME Deprecate
      public static final String PROPERTY_OUTPUT_SAMPLE_RATE =
              "android.media.property.OUTPUT_SAMPLE_RATE";
  
      /**
       * Used as a key for {@link #getProperty} to request the native or optimal output buffer size
       * for this device's low latency output stream, in decimal PCM frames.  Latency-sensitive apps
       * should use this value as a minimum, and offer the user the option to override it.
       * The low latency output stream is typically either the device's primary output stream,
       * or another output stream with smaller buffers.
       */
      // FIXME Deprecate
      public static final String PROPERTY_OUTPUT_FRAMES_PER_BUFFER =
              "android.media.property.OUTPUT_FRAMES_PER_BUFFER";
  
      /**
       * Used as a key for {@link #getProperty} to determine if the default microphone audio source
       * supports near-ultrasound frequencies (range of 18 - 21 kHz).
       */
      public static final String PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND =
              "android.media.property.SUPPORT_MIC_NEAR_ULTRASOUND";
  
      /**
       * Used as a key for {@link #getProperty} to determine if the default speaker audio path
       * supports near-ultrasound frequencies (range of 18 - 21 kHz).
       */
      public static final String PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND =
              "android.media.property.SUPPORT_SPEAKER_NEAR_ULTRASOUND";
  
      /**
       * Used as a key for {@link #getProperty} to determine if the unprocessed audio source is
       * available and supported with the expected frequency range and level response.
       */
      public static final String PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED =
              "android.media.property.SUPPORT_AUDIO_SOURCE_UNPROCESSED";
      /**
       * Returns the value of the property with the specified key.
       * @param key One of the strings corresponding to a property key: either
       *            {@link #PROPERTY_OUTPUT_SAMPLE_RATE},
       *            {@link #PROPERTY_OUTPUT_FRAMES_PER_BUFFER},
       *            {@link #PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND},
       *            {@link #PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND}, or
       *            {@link #PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED}.
       * @return A string representing the associated value for that property key,
       *         or null if there is no value for that key.
       */
      public String getProperty(String key) {
          if (PROPERTY_OUTPUT_SAMPLE_RATE.equals(key)) {
              int outputSampleRate = AudioSystem.getPrimaryOutputSamplingRate();
              return outputSampleRate > 0 ? Integer.toString(outputSampleRate) : null;
          } else if (PROPERTY_OUTPUT_FRAMES_PER_BUFFER.equals(key)) {
              int outputFramesPerBuffer = AudioSystem.getPrimaryOutputFrameCount();
              return outputFramesPerBuffer > 0 ? Integer.toString(outputFramesPerBuffer) : null;
          } else if (PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND.equals(key)) {
              // Will throw a RuntimeException Resources.NotFoundException if this config value is
              // not found.
              return String.valueOf(getContext().getResources().getBoolean(
                      com.android.internal.R.bool.config_supportMicNearUltrasound));
          } else if (PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND.equals(key)) {
              return String.valueOf(getContext().getResources().getBoolean(
                      com.android.internal.R.bool.config_supportSpeakerNearUltrasound));
          } else if (PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED.equals(key)) {
              return String.valueOf(getContext().getResources().getBoolean(
                      com.android.internal.R.bool.config_supportAudioSourceUnprocessed));
          } else {
              // null or unknown key
              return null;
          }
      }
  
      /**
       * Returns the estimated latency for the given stream type in milliseconds.
       *
       * DO NOT UNHIDE. The existing approach for doing A/V sync has too many problems. We need
       * a better solution.
       * @hide
       */
      @UnsupportedAppUsage
      public int getOutputLatency(int streamType) {
          return AudioSystem.getOutputLatency(streamType);
      }
  
      /**
       * Registers a global volume controller interface.  Currently limited to SystemUI.
       *
       * @hide
       */
      public void setVolumeController(IVolumeController controller) {
          try {
              getService().setVolumeController(controller);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Notify audio manager about volume controller visibility changes.
       * Currently limited to SystemUI.
       *
       * @hide
       */
      public void notifyVolumeControllerVisible(IVolumeController controller, boolean visible) {
          try {
              getService().notifyVolumeControllerVisible(controller, visible);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Only useful for volume controllers.
       * @hide
       */
      public boolean isStreamAffectedByRingerMode(int streamType) {
          try {
              return getService().isStreamAffectedByRingerMode(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Only useful for volume controllers.
       * @hide
       */
      public boolean isStreamAffectedByMute(int streamType) {
          try {
              return getService().isStreamAffectedByMute(streamType);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Only useful for volume controllers.
       * @hide
       */
      public void disableSafeMediaVolume() {
          try {
              getService().disableSafeMediaVolume(mApplicationContext.getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Only useful for volume controllers.
       * @hide
       */
      @UnsupportedAppUsage
      public void setRingerModeInternal(int ringerMode) {
          try {
              getService().setRingerModeInternal(ringerMode, getContext().getOpPackageName());
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Only useful for volume controllers.
       * @hide
       */
      @UnsupportedAppUsage
      public int getRingerModeInternal() {
          try {
              return getService().getRingerModeInternal();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Only useful for volume controllers.
       * @hide
       */
      public void setVolumePolicy(VolumePolicy policy) {
          try {
              getService().setVolumePolicy(policy);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Set Hdmi Cec system audio mode.
       *
       * @param on whether to be on system audio mode
       * @return output device type. 0 (DEVICE_NONE) if failed to set device.
       * @hide
       */
      public int setHdmiSystemAudioSupported(boolean on) {
          try {
              return getService().setHdmiSystemAudioSupported(on);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Returns true if Hdmi Cec system audio mode is supported.
       *
       * @hide
       */
      @SystemApi
      @SuppressLint("Doclava125") // FIXME is this still used?
      public boolean isHdmiSystemAudioSupported() {
          try {
              return getService().isHdmiSystemAudioSupported();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * Return codes for listAudioPorts(), createAudioPatch() ...
       */
  
      /** @hide */
      @TestApi
      @SystemApi
      public static final int SUCCESS = AudioSystem.SUCCESS;
      /**
       * A default error code.
       */
      public static final int ERROR = AudioSystem.ERROR;
      /** @hide
       * CANDIDATE FOR PUBLIC API
       */
      public static final int ERROR_BAD_VALUE = AudioSystem.BAD_VALUE;
      /** @hide
       */
      public static final int ERROR_INVALID_OPERATION = AudioSystem.INVALID_OPERATION;
      /** @hide
       */
      public static final int ERROR_PERMISSION_DENIED = AudioSystem.PERMISSION_DENIED;
      /** @hide
       */
      public static final int ERROR_NO_INIT = AudioSystem.NO_INIT;
      /**
       * An error code indicating that the object reporting it is no longer valid and needs to
       * be recreated.
       */
      public static final int ERROR_DEAD_OBJECT = AudioSystem.DEAD_OBJECT;
  
      /**
       * Returns a list of descriptors for all audio ports managed by the audio framework.
       * Audio ports are nodes in the audio framework or audio hardware that can be configured
       * or connected and disconnected with createAudioPatch() or releaseAudioPatch().
       * See AudioPort for a list of attributes of each audio port.
       * @param ports An AudioPort ArrayList where the list will be returned.
       * @hide
       */
      @UnsupportedAppUsage
      public static int listAudioPorts(ArrayList<AudioPort> ports) {
          return updateAudioPortCache(ports, null, null);
      }
  
      /**
       * Returns a list of descriptors for all audio ports managed by the audio framework as
       * it was before the last update calback.
       * @param ports An AudioPort ArrayList where the list will be returned.
       * @hide
       */
      public static int listPreviousAudioPorts(ArrayList<AudioPort> ports) {
          return updateAudioPortCache(null, null, ports);
      }
  
      /**
       * Specialized version of listAudioPorts() listing only audio devices (AudioDevicePort)
       * @see listAudioPorts(ArrayList<AudioPort>)
       * @hide
       */
      public static int listAudioDevicePorts(ArrayList<AudioDevicePort> devices) {
          if (devices == null) {
              return ERROR_BAD_VALUE;
          }
          ArrayList<AudioPort> ports = new ArrayList<AudioPort>();
          int status = updateAudioPortCache(ports, null, null);
          if (status == SUCCESS) {
              filterDevicePorts(ports, devices);
          }
          return status;
      }
  
      /**
       * Specialized version of listPreviousAudioPorts() listing only audio devices (AudioDevicePort)
       * @see listPreviousAudioPorts(ArrayList<AudioPort>)
       * @hide
       */
      public static int listPreviousAudioDevicePorts(ArrayList<AudioDevicePort> devices) {
          if (devices == null) {
              return ERROR_BAD_VALUE;
          }
          ArrayList<AudioPort> ports = new ArrayList<AudioPort>();
          int status = updateAudioPortCache(null, null, ports);
          if (status == SUCCESS) {
              filterDevicePorts(ports, devices);
          }
          return status;
      }
  
      private static void filterDevicePorts(ArrayList<AudioPort> ports,
                                            ArrayList<AudioDevicePort> devices) {
          devices.clear();
          for (int i = 0; i < ports.size(); i++) {
              if (ports.get(i) instanceof AudioDevicePort) {
                  devices.add((AudioDevicePort)ports.get(i));
              }
          }
      }
  
      /**
       * Create a connection between two or more devices. The framework will reject the request if
       * device types are not compatible or the implementation does not support the requested
       * configuration.
       * NOTE: current implementation is limited to one source and one sink per patch.
       * @param patch AudioPatch array where the newly created patch will be returned.
       *              As input, if patch[0] is not null, the specified patch will be replaced by the
       *              new patch created. This avoids calling releaseAudioPatch() when modifying a
       *              patch and allows the implementation to optimize transitions.
       * @param sources List of source audio ports. All must be AudioPort.ROLE_SOURCE.
       * @param sinks   List of sink audio ports. All must be AudioPort.ROLE_SINK.
       *
       * @return - {@link #SUCCESS} if connection is successful.
       *         - {@link #ERROR_BAD_VALUE} if incompatible device types are passed.
       *         - {@link #ERROR_INVALID_OPERATION} if the requested connection is not supported.
       *         - {@link #ERROR_PERMISSION_DENIED} if the client does not have permission to create
       *         a patch.
       *         - {@link #ERROR_DEAD_OBJECT} if the server process is dead
       *         - {@link #ERROR} if patch cannot be connected for any other reason.
       *
       *         patch[0] contains the newly created patch
       * @hide
       */
      @UnsupportedAppUsage
      public static int createAudioPatch(AudioPatch[] patch,
                                   AudioPortConfig[] sources,
                                   AudioPortConfig[] sinks) {
          return AudioSystem.createAudioPatch(patch, sources, sinks);
      }
  
      /**
       * Releases an existing audio patch connection.
       * @param patch The audio patch to disconnect.
       * @return - {@link #SUCCESS} if disconnection is successful.
       *         - {@link #ERROR_BAD_VALUE} if the specified patch does not exist.
       *         - {@link #ERROR_PERMISSION_DENIED} if the client does not have permission to release
       *         a patch.
       *         - {@link #ERROR_DEAD_OBJECT} if the server process is dead
       *         - {@link #ERROR} if patch cannot be released for any other reason.
       * @hide
       */
      @UnsupportedAppUsage
      public static int releaseAudioPatch(AudioPatch patch) {
          return AudioSystem.releaseAudioPatch(patch);
      }
  
      /**
       * List all existing connections between audio ports.
       * @param patches An AudioPatch array where the list will be returned.
       * @hide
       */
      @UnsupportedAppUsage
      public static int listAudioPatches(ArrayList<AudioPatch> patches) {
          return updateAudioPortCache(null, patches, null);
      }
  
      /**
       * Set the gain on the specified AudioPort. The AudioGainConfig config is build by
       * AudioGain.buildConfig()
       * @hide
       */
      public static int setAudioPortGain(AudioPort port, AudioGainConfig gain) {
          if (port == null || gain == null) {
              return ERROR_BAD_VALUE;
          }
          AudioPortConfig activeConfig = port.activeConfig();
          AudioPortConfig config = new AudioPortConfig(port, activeConfig.samplingRate(),
                                          activeConfig.channelMask(), activeConfig.format(), gain);
          config.mConfigMask = AudioPortConfig.GAIN;
          return AudioSystem.setAudioPortConfig(config);
      }
  
      /**
       * Listener registered by client to be notified upon new audio port connections,
       * disconnections or attributes update.
       * @hide
       */
      public interface OnAudioPortUpdateListener {
          /**
           * Callback method called upon audio port list update.
           * @param portList the updated list of audio ports
           */
          public void onAudioPortListUpdate(AudioPort[] portList);
  
          /**
           * Callback method called upon audio patch list update.
           * @param patchList the updated list of audio patches
           */
          public void onAudioPatchListUpdate(AudioPatch[] patchList);
  
          /**
           * Callback method called when the mediaserver dies
           */
          public void onServiceDied();
      }
  
      /**
       * Register an audio port list update listener.
       * @hide
       */
      @UnsupportedAppUsage
      public void registerAudioPortUpdateListener(OnAudioPortUpdateListener l) {
          sAudioPortEventHandler.init();
          sAudioPortEventHandler.registerListener(l);
      }
  
      /**
       * Unregister an audio port list update listener.
       * @hide
       */
      @UnsupportedAppUsage
      public void unregisterAudioPortUpdateListener(OnAudioPortUpdateListener l) {
          sAudioPortEventHandler.unregisterListener(l);
      }
  
      //
      // AudioPort implementation
      //
  
      static final int AUDIOPORT_GENERATION_INIT = 0;
      static Integer sAudioPortGeneration = new Integer(AUDIOPORT_GENERATION_INIT);
      static ArrayList<AudioPort> sAudioPortsCached = new ArrayList<AudioPort>();
      static ArrayList<AudioPort> sPreviousAudioPortsCached = new ArrayList<AudioPort>();
      static ArrayList<AudioPatch> sAudioPatchesCached = new ArrayList<AudioPatch>();
  
      static int resetAudioPortGeneration() {
          int generation;
          synchronized (sAudioPortGeneration) {
              generation = sAudioPortGeneration;
              sAudioPortGeneration = AUDIOPORT_GENERATION_INIT;
          }
          return generation;
      }
  
      static int updateAudioPortCache(ArrayList<AudioPort> ports, ArrayList<AudioPatch> patches,
                                      ArrayList<AudioPort> previousPorts) {
          sAudioPortEventHandler.init();
          synchronized (sAudioPortGeneration) {
  
              if (sAudioPortGeneration == AUDIOPORT_GENERATION_INIT) {
                  int[] patchGeneration = new int[1];
                  int[] portGeneration = new int[1];
                  int status;
                  ArrayList<AudioPort> newPorts = new ArrayList<AudioPort>();
                  ArrayList<AudioPatch> newPatches = new ArrayList<AudioPatch>();
  
                  do {
                      newPorts.clear();
                      status = AudioSystem.listAudioPorts(newPorts, portGeneration);
                      if (status != SUCCESS) {
                          Log.w(TAG, "updateAudioPortCache: listAudioPorts failed");
                          return status;
                      }
                      newPatches.clear();
                      status = AudioSystem.listAudioPatches(newPatches, patchGeneration);
                      if (status != SUCCESS) {
                          Log.w(TAG, "updateAudioPortCache: listAudioPatches failed");
                          return status;
                      }
                      // Loop until patch generation is the same as port generation unless audio ports
                      // and audio patches are not null.
                  } while (patchGeneration[0] != portGeneration[0]
                          && (ports == null || patches == null));
                  // If the patch generation doesn't equal port generation, return ERROR here in case
                  // of mismatch between audio ports and audio patches.
                  if (patchGeneration[0] != portGeneration[0]) {
                      return ERROR;
                  }
  
                  for (int i = 0; i < newPatches.size(); i++) {
                      for (int j = 0; j < newPatches.get(i).sources().length; j++) {
                          AudioPortConfig portCfg = updatePortConfig(newPatches.get(i).sources()[j],
                                                                     newPorts);
                          newPatches.get(i).sources()[j] = portCfg;
                      }
                      for (int j = 0; j < newPatches.get(i).sinks().length; j++) {
                          AudioPortConfig portCfg = updatePortConfig(newPatches.get(i).sinks()[j],
                                                                     newPorts);
                          newPatches.get(i).sinks()[j] = portCfg;
                      }
                  }
                  for (Iterator<AudioPatch> i = newPatches.iterator(); i.hasNext(); ) {
                      AudioPatch newPatch = i.next();
                      boolean hasInvalidPort = false;
                      for (AudioPortConfig portCfg : newPatch.sources()) {
                          if (portCfg == null) {
                              hasInvalidPort = true;
                              break;
                          }
                      }
                      for (AudioPortConfig portCfg : newPatch.sinks()) {
                          if (portCfg == null) {
                              hasInvalidPort = true;
                              break;
                          }
                      }
                      if (hasInvalidPort) {
                          // Temporarily remove patches with invalid ports. One who created the patch
                          // is responsible for dealing with the port change.
                          i.remove();
                      }
                  }
  
                  sPreviousAudioPortsCached = sAudioPortsCached;
                  sAudioPortsCached = newPorts;
                  sAudioPatchesCached = newPatches;
                  sAudioPortGeneration = portGeneration[0];
              }
              if (ports != null) {
                  ports.clear();
                  ports.addAll(sAudioPortsCached);
              }
              if (patches != null) {
                  patches.clear();
                  patches.addAll(sAudioPatchesCached);
              }
              if (previousPorts != null) {
                  previousPorts.clear();
                  previousPorts.addAll(sPreviousAudioPortsCached);
              }
          }
          return SUCCESS;
      }
  
      static AudioPortConfig updatePortConfig(AudioPortConfig portCfg, ArrayList<AudioPort> ports) {
          AudioPort port = portCfg.port();
          int k;
          for (k = 0; k < ports.size(); k++) {
              // compare handles because the port returned by JNI is not of the correct
              // subclass
              if (ports.get(k).handle().equals(port.handle())) {
                  port = ports.get(k);
                  break;
              }
          }
          if (k == ports.size()) {
              // this hould never happen
              Log.e(TAG, "updatePortConfig port not found for handle: "+port.handle().id());
              return null;
          }
          AudioGainConfig gainCfg = portCfg.gain();
          if (gainCfg != null) {
              AudioGain gain = port.gain(gainCfg.index());
              gainCfg = gain.buildConfig(gainCfg.mode(),
                                         gainCfg.channelMask(),
                                         gainCfg.values(),
                                         gainCfg.rampDurationMs());
          }
          return port.buildConfig(portCfg.samplingRate(),
                                                   portCfg.channelMask(),
                                                   portCfg.format(),
                                                   gainCfg);
      }
  
      private OnAmPortUpdateListener mPortListener = null;
  
      /**
       * The message sent to apps when the contents of the device list changes if they provide
       * a {@link Handler} object to addOnAudioDeviceConnectionListener().
       */
      private final static int MSG_DEVICES_CALLBACK_REGISTERED = 0;
      private final static int MSG_DEVICES_DEVICES_ADDED = 1;
      private final static int MSG_DEVICES_DEVICES_REMOVED = 2;
  
      /**
       * The list of {@link AudioDeviceCallback} objects to receive add/remove notifications.
       */
      private final ArrayMap<AudioDeviceCallback, NativeEventHandlerDelegate> mDeviceCallbacks =
              new ArrayMap<AudioDeviceCallback, NativeEventHandlerDelegate>();
  
      /**
       * The following are flags to allow users of {@link AudioManager#getDevices(int)} to filter
       * the results list to only those device types they are interested in.
       */
      /**
       * Specifies to the {@link AudioManager#getDevices(int)} method to include
       * source (i.e. input) audio devices.
       */
      public static final int GET_DEVICES_INPUTS    = 0x0001;
  
      /**
       * Specifies to the {@link AudioManager#getDevices(int)} method to include
       * sink (i.e. output) audio devices.
       */
      public static final int GET_DEVICES_OUTPUTS   = 0x0002;
  
      /**
       * Specifies to the {@link AudioManager#getDevices(int)} method to include both
       * source and sink devices.
       */
      public static final int GET_DEVICES_ALL = GET_DEVICES_OUTPUTS | GET_DEVICES_INPUTS;
  
      /**
       * Determines if a given AudioDevicePort meets the specified filter criteria.
       * @param port  The port to test.
       * @param flags A set of bitflags specifying the criteria to test.
       * @see {@link GET_DEVICES_OUTPUTS} and {@link GET_DEVICES_INPUTS}
       **/
      private static boolean checkFlags(AudioDevicePort port, int flags) {
          return port.role() == AudioPort.ROLE_SINK && (flags & GET_DEVICES_OUTPUTS) != 0 ||
                 port.role() == AudioPort.ROLE_SOURCE && (flags & GET_DEVICES_INPUTS) != 0;
      }
  
      private static boolean checkTypes(AudioDevicePort port) {
          return AudioDeviceInfo.convertInternalDeviceToDeviceType(port.type()) !=
                      AudioDeviceInfo.TYPE_UNKNOWN;
      }
  
      /**
       * Returns an array of {@link AudioDeviceInfo} objects corresponding to the audio devices
       * currently connected to the system and meeting the criteria specified in the
       * <code>flags</code> parameter.
       * @param flags A set of bitflags specifying the criteria to test.
       * @see #GET_DEVICES_OUTPUTS
       * @see #GET_DEVICES_INPUTS
       * @see #GET_DEVICES_ALL
       * @return A (possibly zero-length) array of AudioDeviceInfo objects.
       */
      public AudioDeviceInfo[] getDevices(int flags) {
          return getDevicesStatic(flags);
      }
  
      /**
       * Does the actual computation to generate an array of (externally-visible) AudioDeviceInfo
       * objects from the current (internal) AudioDevicePort list.
       */
      private static AudioDeviceInfo[]
          infoListFromPortList(ArrayList<AudioDevicePort> ports, int flags) {
  
          // figure out how many AudioDeviceInfo we need space for...
          int numRecs = 0;
          for (AudioDevicePort port : ports) {
              if (checkTypes(port) && checkFlags(port, flags)) {
                  numRecs++;
              }
          }
  
          // Now load them up...
          AudioDeviceInfo[] deviceList = new AudioDeviceInfo[numRecs];
          int slot = 0;
          for (AudioDevicePort port : ports) {
              if (checkTypes(port) && checkFlags(port, flags)) {
                  deviceList[slot++] = new AudioDeviceInfo(port);
              }
          }
  
          return deviceList;
      }
  
      /*
       * Calculate the list of ports that are in ports_B, but not in ports_A. This is used by
       * the add/remove callback mechanism to provide a list of the newly added or removed devices
       * rather than the whole list and make the app figure it out.
       * Note that calling this method with:
       *  ports_A == PREVIOUS_ports and ports_B == CURRENT_ports will calculated ADDED ports.
       *  ports_A == CURRENT_ports and ports_B == PREVIOUS_ports will calculated REMOVED ports.
       */
      private static AudioDeviceInfo[] calcListDeltas(
              ArrayList<AudioDevicePort> ports_A, ArrayList<AudioDevicePort> ports_B, int flags) {
  
          ArrayList<AudioDevicePort> delta_ports = new ArrayList<AudioDevicePort>();
  
          AudioDevicePort cur_port = null;
          for (int cur_index = 0; cur_index < ports_B.size(); cur_index++) {
              boolean cur_port_found = false;
              cur_port = ports_B.get(cur_index);
              for (int prev_index = 0;
                   prev_index < ports_A.size() && !cur_port_found;
                   prev_index++) {
                  cur_port_found = (cur_port.id() == ports_A.get(prev_index).id());
              }
  
              if (!cur_port_found) {
                  delta_ports.add(cur_port);
              }
          }
  
          return infoListFromPortList(delta_ports, flags);
      }
  
      /**
       * Generates a list of AudioDeviceInfo objects corresponding to the audio devices currently
       * connected to the system and meeting the criteria specified in the <code>flags</code>
       * parameter.
       * This is an internal function. The public API front is getDevices(int).
       * @param flags A set of bitflags specifying the criteria to test.
       * @see #GET_DEVICES_OUTPUTS
       * @see #GET_DEVICES_INPUTS
       * @see #GET_DEVICES_ALL
       * @return A (possibly zero-length) array of AudioDeviceInfo objects.
       * @hide
       */
      public static AudioDeviceInfo[] getDevicesStatic(int flags) {
          ArrayList<AudioDevicePort> ports = new ArrayList<AudioDevicePort>();
          int status = AudioManager.listAudioDevicePorts(ports);
          if (status != AudioManager.SUCCESS) {
              // fail and bail!
              return new AudioDeviceInfo[0];  // Always return an array.
          }
  
          return infoListFromPortList(ports, flags);
      }
  
      /**
       * Registers an {@link AudioDeviceCallback} object to receive notifications of changes
       * to the set of connected audio devices.
       * @param callback The {@link AudioDeviceCallback} object to receive connect/disconnect
       * notifications.
       * @param handler Specifies the {@link Handler} object for the thread on which to execute
       * the callback. If <code>null</code>, the {@link Handler} associated with the main
       * {@link Looper} will be used.
       */
      public void registerAudioDeviceCallback(AudioDeviceCallback callback,
              android.os.Handler handler) {
          synchronized (mDeviceCallbacks) {
              if (callback != null && !mDeviceCallbacks.containsKey(callback)) {
                  if (mDeviceCallbacks.size() == 0) {
                      if (mPortListener == null) {
                          mPortListener = new OnAmPortUpdateListener();
                      }
                      registerAudioPortUpdateListener(mPortListener);
                  }
                  NativeEventHandlerDelegate delegate =
                          new NativeEventHandlerDelegate(callback, handler);
                  mDeviceCallbacks.put(callback, delegate);
                  broadcastDeviceListChange_sync(delegate.getHandler());
              }
          }
      }
  
      /**
       * Unregisters an {@link AudioDeviceCallback} object which has been previously registered
       * to receive notifications of changes to the set of connected audio devices.
       * @param callback The {@link AudioDeviceCallback} object that was previously registered
       * with {@link AudioManager#registerAudioDeviceCallback} to be unregistered.
       */
      public void unregisterAudioDeviceCallback(AudioDeviceCallback callback) {
          synchronized (mDeviceCallbacks) {
              if (mDeviceCallbacks.containsKey(callback)) {
                  mDeviceCallbacks.remove(callback);
                  if (mDeviceCallbacks.size() == 0) {
                      unregisterAudioPortUpdateListener(mPortListener);
                  }
              }
          }
      }
  
      /**
       * Set port id for microphones by matching device type and address.
       * @hide
       */
      public static void setPortIdForMicrophones(ArrayList<MicrophoneInfo> microphones) {
          AudioDeviceInfo[] devices = getDevicesStatic(AudioManager.GET_DEVICES_INPUTS);
          for (int i = microphones.size() - 1; i >= 0; i--) {
              boolean foundPortId = false;
              for (AudioDeviceInfo device : devices) {
                  if (device.getPort().type() == microphones.get(i).getInternalDeviceType()
                          && TextUtils.equals(device.getAddress(), microphones.get(i).getAddress())) {
                      microphones.get(i).setId(device.getId());
                      foundPortId = true;
                      break;
                  }
              }
              if (!foundPortId) {
                  Log.i(TAG, "Failed to find port id for device with type:"
                          + microphones.get(i).getType() + " address:"
                          + microphones.get(i).getAddress());
                  microphones.remove(i);
              }
          }
      }
  
      /**
       * Convert {@link AudioDeviceInfo} to {@link MicrophoneInfo}.
       * @hide
       */
      public static MicrophoneInfo microphoneInfoFromAudioDeviceInfo(AudioDeviceInfo deviceInfo) {
          int deviceType = deviceInfo.getType();
          int micLocation = (deviceType == AudioDeviceInfo.TYPE_BUILTIN_MIC
                  || deviceType == AudioDeviceInfo.TYPE_TELEPHONY) ? MicrophoneInfo.LOCATION_MAINBODY
                  : deviceType == AudioDeviceInfo.TYPE_UNKNOWN ? MicrophoneInfo.LOCATION_UNKNOWN
                          : MicrophoneInfo.LOCATION_PERIPHERAL;
          MicrophoneInfo microphone = new MicrophoneInfo(
                  deviceInfo.getPort().name() + deviceInfo.getId(),
                  deviceInfo.getPort().type(), deviceInfo.getAddress(), micLocation,
                  MicrophoneInfo.GROUP_UNKNOWN, MicrophoneInfo.INDEX_IN_THE_GROUP_UNKNOWN,
                  MicrophoneInfo.POSITION_UNKNOWN, MicrophoneInfo.ORIENTATION_UNKNOWN,
                  new ArrayList<Pair<Float, Float>>(), new ArrayList<Pair<Integer, Integer>>(),
                  MicrophoneInfo.SENSITIVITY_UNKNOWN, MicrophoneInfo.SPL_UNKNOWN,
                  MicrophoneInfo.SPL_UNKNOWN, MicrophoneInfo.DIRECTIONALITY_UNKNOWN);
          microphone.setId(deviceInfo.getId());
          return microphone;
      }
  
      /**
       * Add {@link MicrophoneInfo} by device information while filtering certain types.
       */
      private void addMicrophonesFromAudioDeviceInfo(ArrayList<MicrophoneInfo> microphones,
                      HashSet<Integer> filterTypes) {
          AudioDeviceInfo[] devices = getDevicesStatic(GET_DEVICES_INPUTS);
          for (AudioDeviceInfo device : devices) {
              if (filterTypes.contains(device.getType())) {
                  continue;
              }
              MicrophoneInfo microphone = microphoneInfoFromAudioDeviceInfo(device);
              microphones.add(microphone);
          }
      }
  
      /**
       * Returns a list of {@link MicrophoneInfo} that corresponds to the characteristics
       * of all available microphones. The list is empty when no microphones are available
       * on the device. An error during the query will result in an IOException being thrown.
       *
       * @return a list that contains all microphones' characteristics
       * @throws IOException if an error occurs.
       */
      public List<MicrophoneInfo> getMicrophones() throws IOException {
          ArrayList<MicrophoneInfo> microphones = new ArrayList<MicrophoneInfo>();
          int status = AudioSystem.getMicrophones(microphones);
          HashSet<Integer> filterTypes = new HashSet<>();
          filterTypes.add(AudioDeviceInfo.TYPE_TELEPHONY);
          if (status != AudioManager.SUCCESS) {
              // fail and populate microphones with unknown characteristics by device information.
              if (status != AudioManager.ERROR_INVALID_OPERATION) {
                  Log.e(TAG, "getMicrophones failed:" + status);
              }
              Log.i(TAG, "fallback on device info");
              addMicrophonesFromAudioDeviceInfo(microphones, filterTypes);
              return microphones;
          }
          setPortIdForMicrophones(microphones);
          filterTypes.add(AudioDeviceInfo.TYPE_BUILTIN_MIC);
          addMicrophonesFromAudioDeviceInfo(microphones, filterTypes);
          return microphones;
      }
  
      /**
       * Returns a list of audio formats that corresponds to encoding formats
       * supported on offload path for A2DP playback.
       *
       * @return a list of {@link BluetoothCodecConfig} objects containing encoding formats
       * supported for offload A2DP playback
       * @hide
       */
      public List<BluetoothCodecConfig> getHwOffloadEncodingFormatsSupportedForA2DP() {
          ArrayList<Integer> formatsList = new ArrayList<Integer>();
          ArrayList<BluetoothCodecConfig> codecConfigList = new ArrayList<BluetoothCodecConfig>();
  
          int status = AudioSystem.getHwOffloadEncodingFormatsSupportedForA2DP(formatsList);
          if (status != AudioManager.SUCCESS) {
              Log.e(TAG, "getHwOffloadEncodingFormatsSupportedForA2DP failed:" + status);
              return codecConfigList;
          }
  
          for (Integer format : formatsList) {
              int btSourceCodec = AudioSystem.audioFormatToBluetoothSourceCodec(format);
              if (btSourceCodec
                      != BluetoothCodecConfig.SOURCE_CODEC_TYPE_INVALID) {
                  codecConfigList.add(new BluetoothCodecConfig(btSourceCodec));
              }
          }
          return codecConfigList;
      }
  
      // Since we need to calculate the changes since THE LAST NOTIFICATION, and not since the
      // (unpredictable) last time updateAudioPortCache() was called by someone, keep a list
      // of the ports that exist at the time of the last notification.
      private ArrayList<AudioDevicePort> mPreviousPorts = new ArrayList<AudioDevicePort>();
  
      /**
       * Internal method to compute and generate add/remove messages and then send to any
       * registered callbacks. Must be called synchronized on mDeviceCallbacks.
       */
      private void broadcastDeviceListChange_sync(Handler handler) {
          int status;
  
          // Get the new current set of ports
          ArrayList<AudioDevicePort> current_ports = new ArrayList<AudioDevicePort>();
          status = AudioManager.listAudioDevicePorts(current_ports);
          if (status != AudioManager.SUCCESS) {
              return;
          }
  
          if (handler != null) {
              // This is the callback for the registration, so send the current list
              AudioDeviceInfo[] deviceList =
                      infoListFromPortList(current_ports, GET_DEVICES_ALL);
              handler.sendMessage(
                      Message.obtain(handler, MSG_DEVICES_CALLBACK_REGISTERED, deviceList));
          } else {
              AudioDeviceInfo[] added_devices =
                      calcListDeltas(mPreviousPorts, current_ports, GET_DEVICES_ALL);
              AudioDeviceInfo[] removed_devices =
                      calcListDeltas(current_ports, mPreviousPorts, GET_DEVICES_ALL);
              if (added_devices.length != 0 || removed_devices.length != 0) {
                  for (int i = 0; i < mDeviceCallbacks.size(); i++) {
                      handler = mDeviceCallbacks.valueAt(i).getHandler();
                      if (handler != null) {
                          if (removed_devices.length != 0) {
                              handler.sendMessage(Message.obtain(handler,
                                      MSG_DEVICES_DEVICES_REMOVED,
                                      removed_devices));
                          }
                          if (added_devices.length != 0) {
                              handler.sendMessage(Message.obtain(handler,
                                      MSG_DEVICES_DEVICES_ADDED,
                                      added_devices));
                          }
                      }
                  }
              }
          }
  
          mPreviousPorts = current_ports;
      }
  
      /**
       * Handles Port list update notifications from the AudioManager
       */
      private class OnAmPortUpdateListener implements AudioManager.OnAudioPortUpdateListener {
          static final String TAG = "OnAmPortUpdateListener";
          public void onAudioPortListUpdate(AudioPort[] portList) {
              synchronized (mDeviceCallbacks) {
                  broadcastDeviceListChange_sync(null);
              }
          }
  
          /**
           * Callback method called upon audio patch list update.
           * Note: We don't do anything with Patches at this time, so ignore this notification.
           * @param patchList the updated list of audio patches.
           */
          public void onAudioPatchListUpdate(AudioPatch[] patchList) {}
  
          /**
           * Callback method called when the mediaserver dies
           */
          public void onServiceDied() {
              synchronized (mDeviceCallbacks) {
                  broadcastDeviceListChange_sync(null);
              }
          }
      }
  
  
      /**
       * @hide
       * Abstract class to receive event notification about audioserver process state.
       */
      @SystemApi
      public abstract static class AudioServerStateCallback {
          public void onAudioServerDown() { }
          public void onAudioServerUp() { }
      }
  
      private Executor mAudioServerStateExec;
      private AudioServerStateCallback mAudioServerStateCb;
      private final Object mAudioServerStateCbLock = new Object();
  
      private final IAudioServerStateDispatcher mAudioServerStateDispatcher =
              new IAudioServerStateDispatcher.Stub() {
          @Override
          public void dispatchAudioServerStateChange(boolean state) {
              Executor exec;
              AudioServerStateCallback cb;
  
              synchronized (mAudioServerStateCbLock) {
                  exec = mAudioServerStateExec;
                  cb = mAudioServerStateCb;
              }
  
              if ((exec == null) || (cb == null)) {
                  return;
              }
              if (state) {
                  exec.execute(() -> cb.onAudioServerUp());
              } else {
                  exec.execute(() -> cb.onAudioServerDown());
              }
          }
      };
  
      /**
       * @hide
       * Registers a callback for notification of audio server state changes.
       * @param executor {@link Executor} to handle the callbacks
       * @param stateCallback the callback to receive the audio server state changes
       *        To remove the callabck, pass a null reference for both executor and stateCallback.
       */
      @SystemApi
      public void setAudioServerStateCallback(@NonNull Executor executor,
              @NonNull AudioServerStateCallback stateCallback) {
          if (stateCallback == null) {
              throw new IllegalArgumentException("Illegal null AudioServerStateCallback");
          }
          if (executor == null) {
              throw new IllegalArgumentException(
                      "Illegal null Executor for the AudioServerStateCallback");
          }
  
          synchronized (mAudioServerStateCbLock) {
              if (mAudioServerStateCb != null) {
                  throw new IllegalStateException(
                      "setAudioServerStateCallback called with already registered callabck");
              }
              final IAudioService service = getService();
              try {
                  service.registerAudioServerStateDispatcher(mAudioServerStateDispatcher);
              } catch (RemoteException e) {
                  throw e.rethrowFromSystemServer();
              }
              mAudioServerStateExec = executor;
              mAudioServerStateCb = stateCallback;
          }
      }
  
      /**
       * @hide
       * Unregisters the callback for notification of audio server state changes.
       */
      @SystemApi
      public void clearAudioServerStateCallback() {
          synchronized (mAudioServerStateCbLock) {
              if (mAudioServerStateCb != null) {
                  final IAudioService service = getService();
                  try {
                      service.unregisterAudioServerStateDispatcher(
                              mAudioServerStateDispatcher);
                  } catch (RemoteException e) {
                      throw e.rethrowFromSystemServer();
                  }
              }
              mAudioServerStateExec = null;
              mAudioServerStateCb = null;
          }
      }
  
      /**
       * @hide
       * Checks if native audioservice is running or not.
       * @return true if native audioservice runs, false otherwise.
       */
      @SystemApi
      public boolean isAudioServerRunning() {
          final IAudioService service = getService();
          try {
              return service.isAudioServerRunning();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Returns all surround formats.
       * @return a map where the key is a surround format and
       * the value indicates the surround format is enabled or not
       */
      public Map<Integer, Boolean> getSurroundFormats() {
          Map<Integer, Boolean> surroundFormats = new HashMap<>();
          int status = AudioSystem.getSurroundFormats(surroundFormats, false);
          if (status != AudioManager.SUCCESS) {
              // fail and bail!
              Log.e(TAG, "getSurroundFormats failed:" + status);
              return new HashMap<Integer, Boolean>(); // Always return a map.
          }
          return surroundFormats;
      }
  
      /**
       * @hide
       * Set a certain surround format as enabled or not.
       * @param audioFormat a surround format, the value is one of
       *        {@link AudioFormat#ENCODING_AC3}, {@link AudioFormat#ENCODING_E_AC3},
       *        {@link AudioFormat#ENCODING_DTS}, {@link AudioFormat#ENCODING_DTS_HD},
       *        {@link AudioFormat#ENCODING_AAC_LC}, {@link AudioFormat#ENCODING_DOLBY_TRUEHD},
       *        {@link AudioFormat#ENCODING_E_AC3_JOC}. Once {@link AudioFormat#ENCODING_AAC_LC} is
       *        set as enabled, {@link AudioFormat#ENCODING_AAC_LC},
       *        {@link AudioFormat#ENCODING_AAC_HE_V1}, {@link AudioFormat#ENCODING_AAC_HE_V2},
       *        {@link AudioFormat#ENCODING_AAC_ELD}, {@link AudioFormat#ENCODING_AAC_XHE} are
       *        all enabled.
       * @param enabled the required surround format state, true for enabled, false for disabled
       * @return true if successful, otherwise false
       */
      public boolean setSurroundFormatEnabled(
              @AudioFormat.SurroundSoundEncoding int audioFormat, boolean enabled) {
          int status = AudioSystem.setSurroundFormatEnabled(audioFormat, enabled);
          return status == AudioManager.SUCCESS;
      }
  
      /**
       * @hide
       * Returns all surround formats that are reported by the connected HDMI device.
       * The keys are not affected by calling setSurroundFormatEnabled(), and the values
       * are not affected by calling setSurroundFormatEnabled() when in AUTO mode.
       * This information can used to show the AUTO setting for SurroundSound.
       *
       * @return a map where the key is a surround format and
       * the value indicates the surround format is enabled or not
       */
      public Map<Integer, Boolean> getReportedSurroundFormats() {
          Map<Integer, Boolean> reportedSurroundFormats = new HashMap<>();
          int status = AudioSystem.getSurroundFormats(reportedSurroundFormats, true);
          if (status != AudioManager.SUCCESS) {
              // fail and bail!
              Log.e(TAG, "getReportedSurroundFormats failed:" + status);
              return new HashMap<Integer, Boolean>(); // Always return a map.
          }
          return reportedSurroundFormats;
      }
  
      /**
       * Return if audio haptic coupled playback is supported or not.
       *
       * @return whether audio haptic playback supported.
       */
      public static boolean isHapticPlaybackSupported() {
          return AudioSystem.isHapticPlaybackSupported();
      }
  
      /**
       * @hide
       * Introspection API to retrieve audio product strategies.
       * When implementing {Car|Oem}AudioManager, use this method  to retrieve the collection of
       * audio product strategies, which is indexed by a weakly typed index in order to be extended
       * by OEM without any needs of AOSP patches.
       * The {Car|Oem}AudioManager can expose API to build {@link AudioAttributes} for a given product
       * strategy refered either by its index or human readable string. It will allow clients
       * application to start streaming data using these {@link AudioAttributes} on the selected
       * device by Audio Policy Engine.
       * @return a (possibly zero-length) array of
       *         {@see android.media.audiopolicy.AudioProductStrategy} objects.
       */
      @SystemApi
      @NonNull
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public static List<AudioProductStrategy> getAudioProductStrategies() {
          final IAudioService service = getService();
          try {
              return service.getAudioProductStrategies();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Introspection API to retrieve audio volume groups.
       * When implementing {Car|Oem}AudioManager, use this method  to retrieve the collection of
       * audio volume groups.
       * @return a (possibly zero-length) List of
       *         {@see android.media.audiopolicy.AudioVolumeGroup} objects.
       */
      @SystemApi
      @NonNull
      @RequiresPermission(android.Manifest.permission.MODIFY_AUDIO_ROUTING)
      public static List<AudioVolumeGroup> getAudioVolumeGroups() {
          final IAudioService service = getService();
          try {
              return service.getAudioVolumeGroups();
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      /**
       * @hide
       * Callback registered by client to be notified upon volume group change.
       */
      @SystemApi
      public abstract static class VolumeGroupCallback {
          /**
           * Callback method called upon audio volume group change.
           * @param group the group for which the volume has changed
           */
          public void onAudioVolumeGroupChanged(int group, int flags) {}
      }
  
     /**
      * @hide
      * Register an audio volume group change listener.
      * @param callback the {@link VolumeGroupCallback} to register
      */
      @SystemApi
      public void registerVolumeGroupCallback(
              @NonNull Executor executor,
              @NonNull VolumeGroupCallback callback) {
          Preconditions.checkNotNull(executor, "executor must not be null");
          Preconditions.checkNotNull(callback, "volume group change cb must not be null");
          sAudioAudioVolumeGroupChangedHandler.init();
          // TODO: make use of executor
          sAudioAudioVolumeGroupChangedHandler.registerListener(callback);
      }
  
     /**
      * @hide
      * Unregister an audio volume group change listener.
      * @param callback the {@link VolumeGroupCallback} to unregister
      */
      @SystemApi
      public void unregisterVolumeGroupCallback(
              @NonNull VolumeGroupCallback callback) {
          Preconditions.checkNotNull(callback, "volume group change cb must not be null");
          sAudioAudioVolumeGroupChangedHandler.unregisterListener(callback);
      }
  
      /**
       * Return if an asset contains haptic channels or not.
       * @param uri the {@link Uri} of the asset.
       * @return true if the assert contains haptic channels.
       * @hide
       */
      public static boolean hasHapticChannels(Uri uri) {
          try {
              return getService().hasHapticChannels(uri);
          } catch (RemoteException e) {
              throw e.rethrowFromSystemServer();
          }
      }
  
      //---------------------------------------------------------
      // Inner classes
      //--------------------
      /**
       * Helper class to handle the forwarding of native events to the appropriate listener
       * (potentially) handled in a different thread.
       */
      private class NativeEventHandlerDelegate {
          private final Handler mHandler;
  
          NativeEventHandlerDelegate(final AudioDeviceCallback callback,
                                     Handler handler) {
              // find the looper for our new event handler
              Looper looper;
              if (handler != null) {
                  looper = handler.getLooper();
              } else {
                  // no given handler, use the looper the addListener call was called in
                  looper = Looper.getMainLooper();
              }
  
              // construct the event handler with this looper
              if (looper != null) {
                  // implement the event handler delegate
                  mHandler = new Handler(looper) {
                      @Override
                      public void handleMessage(Message msg) {
                          switch(msg.what) {
                          case MSG_DEVICES_CALLBACK_REGISTERED:
                          case MSG_DEVICES_DEVICES_ADDED:
                              if (callback != null) {
                                  callback.onAudioDevicesAdded((AudioDeviceInfo[])msg.obj);
                              }
                              break;
  
                          case MSG_DEVICES_DEVICES_REMOVED:
                              if (callback != null) {
                                  callback.onAudioDevicesRemoved((AudioDeviceInfo[])msg.obj);
                              }
                             break;
  
                          default:
                              Log.e(TAG, "Unknown native event type: " + msg.what);
                              break;
                          }
                      }
                  };
              } else {
                  mHandler = null;
              }
          }
  
          Handler getHandler() {
              return mHandler;
          }
      }
  }
  