private void stopGesture() {
    if (mGestureInProgress) {
      mGestureInProgress = false;
      if (mListener != null) {
        mListener.onGestureEnd(this);
      }
    }
  }
Stops the current gesture and calls the listener right after stopping it.
samples/gestures/src/main/java/com/facebook/samples/gestures/MultiPointerGestureDetector.java