How to change the background of the application when you click the square button (recent applications)?
I already researched and some indicated using onPause and onStart to change the background using
getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE,
WindowManager.LayoutParams.FLAG_SECURE);
Only when you get a change of screen, it ends up setting the background. So I need to know if you can set this background only when you press the button that shows the recent app (square).
My goal is to hide the contents of the activity when there is an application change when you press home and reopen the application when you press the square.
This is the button quoted:
SimilartothisexampleofthisappforiOS 