Pokemon GO does not run when the screen is off which means that the screen must be on and unlocked to be able to catch Pokemon or detect steps for hatching eggs.
This app allows you to tap a button to lock and black out the screen but keep Pokemon GO running.
This means you can save battery life while walking around by putting the screen in a lower power state, and you to safely put your phone in your pocket without worrying about pocket dialing or accidentally pressing other buttons when your phone is on and in your pocket.
How to use?
Wake Lock – Used to keep the screen on while the Download GO lock screen is active
System Alert Window – Used to overlay the lockscreen over top of Pokemon GO