code: @Override
      public boolean onTouchEvent(MotionEvent event) {
          if (isEnabled()) {
              switch (event.getAction()) {
                  case MotionEvent.ACTION_DOWN:
                      isSelected = true;
                      break;
  
                  case MotionEvent.ACTION_UP:
                  case MotionEvent.ACTION_CANCEL:
                      isSelected = false;
                      break;
              }
              invalidate();
          }
          return super.onTouchEvent(event);
      }
docs: /*
  **********************************************************************************
  LISTENER METHODS
  **********************************************************************************