How to blur background images in Android

The easiest way to do that is use a library. Take a look at this one: https://github.com/wasabeef/Blurry

With the library you only need to do this:

Blurry.with(context)
  .radius(10)
  .sampling(8)
  .color(Color.argb(66, 255, 255, 0))
  .async()
  .onto(rootView);