How to create animated background gradient like Instagram app?

Question

Below are screenshots of instagram app. The background keeps on transforming from one gradient to other very beautifully.

I want to know how can I achieve

Answer 1

Create a TransitionDrawable to change between two drawables that you use for the background.

Transition Drawables in Android

TransitionDrawable trans = (TransitionDrawable) myLayout.getBackground();
trans.startTransition(2000);