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.

<?xml version="1.0" encoding="UTF-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- use whatever drawables you want, gradients, shapes etc-->
    <item android:drawable="@drawable/start" />
    <item android:drawable="@drawable/end" />
</transition>

Transition Drawables in Android

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