content: /*
   * Copyright (C) 2014 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.android.server.am;
  
  import android.app.AlertDialog;
  import android.content.Context;
  import android.content.pm.UserInfo;
  import android.content.res.Resources;
  import android.os.Handler;
  import android.os.Message;
  import android.os.UserHandle;
  import android.os.UserManager;
  import android.util.Slog;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewTreeObserver;
  import android.view.WindowManager;
  import android.widget.TextView;
  
  import com.android.internal.R;
  import com.android.internal.annotations.GuardedBy;
  
  /**
   * Dialog to show when a user switch it about to happen. The intent is to snapshot the screen
   * immediately after the dialog shows so that the user is informed that something is happening
   * in the background rather than just freeze the screen and not know if the user-switch affordance
   * was being handled.
   */
  class UserSwitchingDialog extends AlertDialog
          implements ViewTreeObserver.OnWindowShownListener {
      private static final String TAG = "ActivityManagerUserSwitchingDialog";
  
      // Time to wait for the onWindowShown() callback before continuing the user switch
      private static final int WINDOW_SHOWN_TIMEOUT_MS = 3000;
  
      // User switching doesn't happen that frequently, so it doesn't hurt to have it always on
      protected static final boolean DEBUG = true;
  
      private final ActivityManagerService mService;
      private final int mUserId;
      private static final int MSG_START_USER = 1;
      @GuardedBy("this")
      private boolean mStartedUser;
      final protected UserInfo mOldUser;
      final protected UserInfo mNewUser;
      final private String mSwitchingFromSystemUserMessage;
      final private String mSwitchingToSystemUserMessage;
      final protected Context mContext;
  
      public UserSwitchingDialog(ActivityManagerService service, Context context, UserInfo oldUser,
              UserInfo newUser, boolean aboveSystem, String switchingFromSystemUserMessage,
              String switchingToSystemUserMessage) {
          super(context);
  
          mContext = context;
          mService = service;
          mUserId = newUser.id;
          mOldUser = oldUser;
          mNewUser = newUser;
          mSwitchingFromSystemUserMessage = switchingFromSystemUserMessage;
          mSwitchingToSystemUserMessage = switchingToSystemUserMessage;
  
          inflateContent();
  
          if (aboveSystem) {
              getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ERROR);
          }
  
          WindowManager.LayoutParams attrs = getWindow().getAttributes();
          attrs.privateFlags = WindowManager.LayoutParams.PRIVATE_FLAG_SYSTEM_ERROR |
              WindowManager.LayoutParams.PRIVATE_FLAG_SHOW_FOR_ALL_USERS;
          getWindow().setAttributes(attrs);
      }
  
      void inflateContent() {
          // Set up the dialog contents
          setCancelable(false);
          Resources res = getContext().getResources();
          // Custom view due to alignment and font size requirements
          View view = LayoutInflater.from(getContext()).inflate(R.layout.user_switching_dialog,
              null);
  
          String viewMessage = null;
          if (UserManager.isSplitSystemUser() && mNewUser.id == UserHandle.USER_SYSTEM) {
              viewMessage = res.getString(R.string.user_logging_out_message, mOldUser.name);
          } else if (UserManager.isDeviceInDemoMode(mContext)) {
              if (mOldUser.isDemo()) {
                  viewMessage = res.getString(R.string.demo_restarting_message);
              } else {
                  viewMessage = res.getString(R.string.demo_starting_message);
              }
          } else {
              if (mOldUser.id == UserHandle.USER_SYSTEM) {
                  viewMessage = mSwitchingFromSystemUserMessage;
              } else if (mNewUser.id == UserHandle.USER_SYSTEM) {
                  viewMessage = mSwitchingToSystemUserMessage;
              }
  
              // If switchingFromSystemUserMessage or switchingToSystemUserMessage is null, fallback
              // to system message.
              if (viewMessage == null) {
                  viewMessage = res.getString(R.string.user_switching_message, mNewUser.name);
              }
          }
          ((TextView) view.findViewById(R.id.message)).setText(viewMessage);
          setView(view);
      }
  
      @Override
      public void show() {
          if (DEBUG) Slog.d(TAG, "show called");
          super.show();
          final View decorView = getWindow().getDecorView();
          if (decorView != null) {
              decorView.getViewTreeObserver().addOnWindowShownListener(this);
          }
          // Add a timeout as a safeguard, in case a race in screen on/off causes the window
          // callback to never come.
          mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_START_USER),
                  WINDOW_SHOWN_TIMEOUT_MS);
      }
  
      @Override
      public void onWindowShown() {
          if (DEBUG) Slog.d(TAG, "onWindowShown called");
          startUser();
      }
  
      void startUser() {
          synchronized (this) {
              if (!mStartedUser) {
                  Slog.i(TAG, "starting user " + mUserId);
                  mService.mUserController.startUserInForeground(mUserId);
                  dismiss();
                  mStartedUser = true;
                  final View decorView = getWindow().getDecorView();
                  if (decorView != null) {
                      decorView.getViewTreeObserver().removeOnWindowShownListener(this);
                  }
                  mHandler.removeMessages(MSG_START_USER);
              } else {
                  Slog.i(TAG, "user " + mUserId + " already started");
              }
          }
      }
  
      private final Handler mHandler = new Handler() {
          @Override
          public void handleMessage(Message msg) {
              switch (msg.what) {
                  case MSG_START_USER:
                      Slog.w(TAG, "user switch window not shown in "
                              + WINDOW_SHOWN_TIMEOUT_MS + " ms");
                      startUser();
                      break;
              }
          }
      };
  }
  