java - How to draw a view on top of everything?

Question

I want to make an app that can create notification on the screen on top of anything that is currently being displayed. Something like the Go SMS message popup or something like the ChatHead in the following picture:

It would be even better if it is possible to draw it dynamically including touch events.What is the conventional or standard way to do this?

Example:

Like an Icon that can be clicked or dragged no matter whether you are on home screen or app drawer or other apps.Pay attention to the circular icons near the edges of the screen in the picture posted. You can drag them anywhere in any app.

Answer 1

What you are looking for is System Alert Window.

There's a library called StandOut! which will assist you in creating such apps.