public void onIndicatorEvent(int event) {
    switch (event) {
      case OnIndicatorEventListener.EVENT_ENTER_ZOOM_CONTROL:
        mIndicatorControlWheel.setVisibility(View.GONE);
        mZoomControlWheel.setVisibility(View.VISIBLE);
        mZoomControlWheel.startZoomControl();
        break;

      case OnIndicatorEventListener.EVENT_LEAVE_ZOOM_CONTROL:
        mZoomControlWheel.setVisibility(View.GONE);
        mIndicatorControlWheel.setVisibility(View.VISIBLE);
        break;
    }
  }