How to use

MediaControllerCompat$Callback

in

android.support.v4.media.session

  @Override
  public void onSessionDestroyed() {
    super.onSessionDestroyed();
    Log.d(TAG, "Session was destroyed, resetting to the new session token");
    try {
      updateSessionToken();
    } catch (RemoteException e) {
      Log.e(TAG, "could not connect media controller", e);
    }
  }
};

@Override
public void onPlaybackStateChanged(PlaybackStateCompat state) {
  super.onPlaybackStateChanged(state);
  // If there's an ongoing animation, stop it now.
  if (mProgressAnimator != null) {
    mProgressAnimator.cancel();
    mProgressAnimator = null;
  }
  final int progress = state != null
      ? (int) state.getPosition()
      : 0;
  setProgress(progress);
  // If the media is playing then the seekbar should follow it, and the easiest
  // way to do that is to create a ValueAnimator to update it so the bar reaches
  // the end of the media the same time as playback gets there (or close enough).
  if (state != null && state.getState() == PlaybackStateCompat.STATE_PLAYING) {
    final int timeToEnd = (int) ((getMax() - progress) / state.getPlaybackSpeed());
    mProgressAnimator = ValueAnimator.ofInt(progress, getMax())
        .setDuration(timeToEnd);
    mProgressAnimator.setInterpolator(new LinearInterpolator());
    mProgressAnimator.addUpdateListener(this);
    mProgressAnimator.start();
  }
}

@Override
public void onMetadataChanged(MediaMetadataCompat metadata) {
  super.onMetadataChanged(metadata);
  mMetadata = metadata;
  Notification notification = createNotification();
  if (notification != null) {
    mNotificationManager.notify(NOTIFICATION_ID, notification);
  }
}

@Override
public void onPlaybackStateChanged(PlaybackStateCompat state) {
  super.onPlaybackStateChanged(state);
  playbackState = state != null ? state : EMPTY_PLAYBACK_STATE;

@Override
public void onMetadataChanged(MediaMetadataCompat metadata) {
  super.onMetadataChanged(metadata);
  nowPlaying = metadata != null ? metadata : NOTHING_PLAYING;
  //状态监听
  CopyOnWriteArrayList<OnPlayerEventListener> mPlayerEventListeners = MusicManager.getInstance().getPlayerEventListeners();
  if (metadata != null) {
    SongInfo songInfo = null;
    for (OnPlayerEventListener listener : mPlayerEventListeners) {
      List<SongInfo> songInfos = MusicProvider.getInstance().getSongInfos();
      for (SongInfo info : songInfos) {
        if (info.getSongId().equals(metadata.getString(MediaMetadataCompat.METADATA_KEY_MEDIA_ID))) {
          songInfo = info;
          break;
        }
      }
      listener.onMusicSwitch(songInfo);
    }
  }
}

  @Override
  public void onConnected() {
    Log.d(TAG, "MediaBrowser connected");
    try {
      MediaControllerCompat mediaController = new MediaControllerCompat(
          TomahawkMainActivity.this, mMediaBrowser.getSessionToken());
      setSupportMediaController(mediaController);
      mediaController.registerCallback(mMediaCallback);
      mPlaybackPanel.setMediaController(mediaController);
      mMediaCallback.onPlaybackStateChanged(mediaController.getPlaybackState());
      ContentHeaderFragment.MediaControllerConnectedEvent event
          = new ContentHeaderFragment.MediaControllerConnectedEvent();
      EventBus.getDefault().post(event);
    } catch (RemoteException e) {
      Log.e(TAG, "Could not connect media controller: ", e);
    }
  }
};

public void registerCallback(Callback callback) {
  if (callback != null) {
    mCallbackList.add(callback);
    // Update with the latest metadata/playback state.
    if (mMediaController != null) {
      final MediaMetadataCompat metadata = mMediaController.getMetadata();
      if (metadata != null) {
        callback.onMetadataChanged(metadata);
      }
      final PlaybackStateCompat playbackState = mMediaController.getPlaybackState();
      if (playbackState != null) {
        callback.onPlaybackStateChanged(playbackState);
      }
    }
  }
}

@Override
public void onPlaybackStateChanged(PlaybackStateCompat state) {
  super.onPlaybackStateChanged(state);
  mPlaybackState = state;
  if (state.getState() == PlaybackStateCompat.STATE_STOPPED || state.getState() == PlaybackStateCompat.STATE_NONE) {
    stopNotification();
  } else {
    Notification notification = createNotification();
    if (notification != null) {
      mNotificationManager.notify(NOTIFICATION_ID, notification);
    }
  }
}

@Override
public void onPlaybackStateChanged(Object stateObj) {
  Callback.this.onPlaybackStateChanged(
      PlaybackStateCompat.fromPlaybackState(stateObj));
}

@Override
public void onSessionDestroyed() {
  super.onSessionDestroyed();
}

@Override
public void onSessionDestroyed() {
  super.onSessionDestroyed();
}

@Override
public void onSessionDestroyed() {
  Callback.this.onSessionDestroyed();
}

@Override
public void onPlaybackStateChanged(PlaybackStateCompat state) {
  super.onPlaybackStateChanged(state);
  mPlaybackState = state;
  if (state.getState() == PlaybackStateCompat.STATE_STOPPED || state.getState() == PlaybackStateCompat.STATE_NONE) {
    stopNotification();
  } else {
    Notification notification = createNotification();
    if (notification != null) {
      mNotificationManager.notify(NOTIFICATION_ID, notification);
    }
  }
}

@Override
public void onSessionEvent(String event, Bundle extras) {
  Callback.this.onSessionEvent(event, extras);
}

  @Override
  public void perform(@NonNull Callback callback) {
    callback.onPlaybackStateChanged(state);
  }
});

  @Override
  public void onQueueChanged(List<MediaSessionCompat.QueueItem> queue) {
    super.onQueueChanged(queue);
  }
}

  @Override
  public void onSessionDestroyed() {
    super.onSessionDestroyed();
    try {
      updateSessionToken();
    } catch (RemoteException e) {
      e.printStackTrace();
    }
  }
};

  @Override
  public void onSessionDestroyed() {
    super.onSessionDestroyed();
    mediaBrowserConnectionCallback.onConnectionSuspended();
  }
}

  @Override
  public void onSessionDestroyed() {
    super.onSessionDestroyed();
    try {
      updateSessionToken();
    } catch (RemoteException e) {
      e.printStackTrace();
    }
  }
};

  @Override
  public void perform(@NonNull Callback callback) {
    callback.onPlaybackStateChanged(null);
  }
});