Android - Click Listener for Custom Views

      Custom views in android come in all sizes, shapes and forms. Besides, complex views would like to notify of a click only when a part of the view is clicked. This could specially be a challenge for custom views based on View. This could be achieved via Android's Region API. The logic is to create a region corresponding to the desired section of the view and check if the touch coordinates notified via onTouch(...) falls in the specific region.

  final Region region = new Region( left, top, right, bottom );

  public boolean onTouchEvent(MotionEvent event) {

        float x = event.getX();
        float y = event.getY();

        switch (event.getAction()) {

            case MotionEvent.ACTION_UP: {
                if (region.contains((int) x, (int) y)) {
                      notifyOnClickListeners();
                }
            }
            break;
        }

        return super.onTouchEvent(event);
    }