Android Button按下和松开监听

Button btn = (Button)findViewById(R.id.button);
btn.setOnTouchListener(buttonListener);

private OnTouchListener buttonListener = new OnTouchListener() {

 public boolean onTouch(View arg0, MotionEvent event) {
  // TODO Auto-generated method stub
  int action = event.getAction();
  if (action == MotionEvent.ACTION_DOWN) { // 按下

     } else if (action == MotionEvent.ACTION_UP) { // 松开   
  }
  return false; 

 }  
};