android MotionEvent.ACTION_DOWN and ACTION_UP questions simple questions, solving

A button to capture and ACTION_UP ACTION_DOWN touch screen operation, down to the button when setting a bright background in the up position when setting a gray background, and why, when clicking quickly (like double) is not normal? The results highlight the background image is always displayed, why ah? ? ?

case R.id.ptz_down_btn:
switch (event.getAction ()) {
case MotionEvent.ACTION_DOWN :/ / Screen Press
Log.e ("11111111111", "11111111111");
                                                 down_btn.setBackgroundDrawable (this.getResources (). getDrawable (
                       R.drawable.ptz_down_focus)) ;/ / button pressed highlight background image, click on and then set when lifting gray;
break;
case MotionEvent.ACTION_UP :/ / Press lifted
Log.e ("22222", "2222222222222");
down_btn.setBackgroundDrawable (this.getResources ()
                             . getDrawable (R.drawable.ptz_down_blur)) ;/ / button pressed highlight background image, click on and then set when lifting gray;
break;
}
break;

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R.id.ptz_down_btn is a button? Why do you use event.getAction () do touch judge?
Why not
Java code

button.setOnClickListener (new OnClickListener () {
             @ Override
             public void onClick (View v) {
                 / / Here to see to sense the time the button is pressed
             }
         });


If you really want to use event.getAction ()

Should override the parent class method onTouchEvent

Java code

         / / Here the judge is pressed! ! !
     @ Override
     public boolean onTouchEvent (MotionEvent event) {
         / / Get the coordinates of the touch
         int x = (int) event.getX ();
         int y = (int) event.getY ();
         switch (event.getAction ()) {
         / / Touch screen moments
         case MotionEvent.ACTION_DOWN:
             UpdateTouchEvent (x, y);
             break;
         / / Touch and move the moment
         case MotionEvent.ACTION_MOVE:
             break;
         / / End touch moments
         case MotionEvent.ACTION_UP:
             break;
         }
         return super.onTouchEvent (event);
     }


The desire to help the landlord! !

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Double-click the listener achieve