Facebook Messenger - bubble-popup

Question

How to make a bubble-popup?

It's about showing the other applications, and transparency.

https://i.sstatic.net/iRdaZ.jpg

(Sorry for my language, I write with a translator.)

Answer 1

I cannot mark this as a duplicate, but there are some other questions here about this:

How to make a Facebook Messenger-like notification like this in Android

How to draw a view on top of everything?

Everything is based on:

http://developer.android.com/reference/android/Manifest.permission.html#SYSTEM_ALERT_WINDOW