How to add animation on notification bubble button Android?

Question

I got a notification bubble button. How can I implement animation of slow fading (disappearing) when I drag it on removal position. Now its just disappear immediately but I need to add animation.

I've found a place to call animation and correct view to interact with. But for some reason animation does not work

Here is the code

        myView.startAnimation(AnimationUtils.loadAnimation(this, R.anim.my_animation))

Thats the example