how to completely block android apps from running in the background

many of android apps steel work after user stop use it that eat batterie CPU and ram but now i will show you how to #completely block android apps from running in the background

firstly you need a rooted phone you can read this article for how to do that best 6 android apps for one click root

secondly you need exposed installer if you have android 4.4 and down go to official site and download it For Android 5.0 or higher (Lollipop/Marshmallow), these versions don't work! Use this instead: xda-developers article

now install 3c toolbox and give he root and exposed permission

finely go to apps tab on apps manager select the apps you want to block (be careful don't select must run system apps that will break your phone) and click manage after that click crystallization now that apps are not allowed to run in background :)