Question

For example I have an app that counts how many time Camera button was pressed. After locking the screen the app is not working, so is there any way to keep counting presses when screen is locked?

Answer 1

Running Apps and services are pause when the phone is locked, but you can acquire WAKE_LOCK key and do your task

PowerManager mgr = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
WakeLock wakeLock = mgr.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,"MyWakeLock"); 
wakeLock.acquire();

this will hold the CPU open even if the screen off