Media Session Callbacks

Your media session callbacks call methods in several APIs to control the player, manage the audio focus, and communicate with the media session and media browser service. The following table summarizes how these tasks are distributed across callbacks.

Here is a sample framework for the callback:

private IntentFilter intentFilter = new IntentFilter(AudioManager.ACTION_AUDIO_BECOMING_NOISY);

// Defined elsewhere...
private AudioManager.OnAudioFocusChangeListener afChangeListener;
private BecomingNoisyReceiver myNoisyAudioStreamReceiver = new BecomingNoisyReceiver();
private MediaStyleNotification myPlayerNotification;
private MediaSessionCompat mediaSession;
private MediaBrowserService service;
private SomeKindOfPlayer player;

MediaSessionCompat.Callback callback = new
MediaSessionCompat.Callback() {
  @Override
  public void onPlay() {
    AudioManager am = mContext.getSystemService(Context.AUDIO_SERVICE);
    // Request audio focus for playback, this registers the afChangeListener
    int result = am.requestAudioFocus(afChangeListener,
                                 // Use the music stream.
                                 AudioManager.STREAM_MUSIC,
                                 // Request permanent focus.
                                 AudioManager.AUDIOFOCUS_GAIN);

    if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
      // Start the service
      service.start();
      // Set the session active  (and update metadata and state)
      mediaSession.setActive(true);
      // start the player (custom call)
      player.start();
      // Register BECOME_NOISY BroadcastReceiver
      registerReceiver(myNoisyAudioStreamReceiver, intentFilter);
      // Put the service in the foreground, post notification
      service.startForeground(myPlayerNotification);
    }
  }

  @Override
  public void onStop() {
    AudioManager am = mContext.getSystemService(Context.AUDIO_SERVICE);
    // Abandon audio focus
    am.abandonAudioFocus(afChangeListener);
    unregisterReceiver(myNoisyAudioStreamReceiver);
    // Start the service
    service.stop(self);
    // Set the session inactive  (and update metadata and state)
    mediaSession.setActive(false);
    // stop the player (custom call)
    player.stop();
    // Take the service out of the foreground, remove notification
    service.stopForeground(true);
  }

  @Override
  public void onPause() {
    AudioManager am = mContext.getSystemService(Context.AUDIO_SERVICE);
    // Update metadata and state
    // pause the player (custom call)
    player.pause();
    // unregister BECOME_NOISY BroadcastReceiver
    unregisterReceiver(myNoisyAudioStreamReceiver, intentFilter);
    // Take the service out of the foreground, retain the notification
    service.stopForeground(false);
  }
}