animation not work

[Blaster-777]

i write a simple animation with 500 ms duration and set it to progress bar but it disappear immediately without duration effect.

AlphaAnimation fadeOut = new AlphaAnimation(1.0f, 0.0f);
fadeOut.setDuration(500);
circularProgress.startAnimation(fadeOut);

[FitsumKurabachew]

AlphaAnimation fadeOut = new AlphaAnimation(1.0f, 0.0f);
fadeOut.setDuration(500);
circularProgress.startAnimation(fadeOut);