@Override
  protected void onCreate(Bundle savedInstanceState) {
    Log.e(TAG, "onCreate");
    super.onCreate(savedInstanceState);

    MyAppApplication myApp = ((MyAppApplication) getApplicationContext());
    mGoogleApiClient = myApp.getClient();
    room = myApp.getRoom();
    mRoomId = room.getRoomId();
    mParticipants = room.getParticipants();

    Intent i = getIntent();
    myself = (Player) i.getSerializableExtra("myself");

    AndroidApplicationConfiguration config = new AndroidApplicationConfiguration();
    initialize(new CatMath(this, myself), config); // updated by siyuan

    myId = room.getParticipantId(Games.Players.getCurrentPlayerId(myApp.getClient()));
    GameWorld.isOwner = isServer();
    Log.e("isOwner:", String.valueOf(GameWorld.isOwner));
    playerMap.put(myId, 1);
    GameWorld.numberOfPlayers = mParticipants.size();

    Log.e(TAG, "onCreate ends");
  } // end of onCreate