content: /*
   * Copyright (C) 2016 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 com.google.android.exoplayer2.audio;
  
  import android.content.BroadcastReceiver;
  import android.content.Context;
  import android.content.Intent;
  import android.content.IntentFilter;
  import android.media.AudioManager;
  import com.google.android.exoplayer2.util.Assertions;
  import com.google.android.exoplayer2.util.Util;
  
  /**
   * Receives broadcast events indicating changes to the device's audio capabilities, notifying a
   * {@link Listener} when audio capability changes occur.
   */
  public final class AudioCapabilitiesReceiver {
  
    /**
     * Listener notified when audio capabilities change.
     */
    public interface Listener {
  
      /**
       * Called when the audio capabilities change.
       *
       * @param audioCapabilities The current audio capabilities for the device.
       */
      void onAudioCapabilitiesChanged(AudioCapabilities audioCapabilities);
  
    }
  
    private final Context context;
    private final Listener listener;
    private final BroadcastReceiver receiver;
  
    /* package */ AudioCapabilities audioCapabilities;
  
    /**
     * @param context A context for registering the receiver.
     * @param listener The listener to notify when audio capabilities change.
     */
    public AudioCapabilitiesReceiver(Context context, Listener listener) {
      this.context = Assertions.checkNotNull(context);
      this.listener = Assertions.checkNotNull(listener);
      this.receiver = Util.SDK_INT >= 21 ? new HdmiAudioPlugBroadcastReceiver() : null;
    }
  
    /**
     * Registers the receiver, meaning it will notify the listener when audio capability changes
     * occur. The current audio capabilities will be returned. It is important to call
     * {@link #unregister} when the receiver is no longer required.
     *
     * @return The current audio capabilities for the device.
     */
    @SuppressWarnings("InlinedApi")
    public AudioCapabilities register() {
      Intent stickyIntent = receiver == null ? null
          : context.registerReceiver(receiver, new IntentFilter(AudioManager.ACTION_HDMI_AUDIO_PLUG));
      audioCapabilities = AudioCapabilities.getCapabilities(stickyIntent);
      return audioCapabilities;
    }
  
    /**
     * Unregisters the receiver, meaning it will no longer notify the listener when audio capability
     * changes occur.
     */
    public void unregister() {
      if (receiver != null) {
        context.unregisterReceiver(receiver);
      }
    }
  
    private final class HdmiAudioPlugBroadcastReceiver extends BroadcastReceiver {
  
      @Override
      public void onReceive(Context context, Intent intent) {
        if (!isInitialStickyBroadcast()) {
          AudioCapabilities newAudioCapabilities = AudioCapabilities.getCapabilities(intent);
          if (!newAudioCapabilities.equals(audioCapabilities)) {
            audioCapabilities = newAudioCapabilities;
            listener.onAudioCapabilitiesChanged(newAudioCapabilities);
          }
        }
      }
  
    }
  
  }
  