blink ImageView

code snippet

    final Animation animation = new AlphaAnimation(1, 0);
    animation.setDuration(1000); 
    animation.setInterpolator(new LinearInterpolator()); 
    animation.setRepeatCount(Animation.INFINITE); 
    animation.setRepeatMode(Animation.REVERSE); 
    imageButton.startAnimation(animation);

Set the background of ImageView as Transparent.