This application is the best solution On-Off screen.
For all smartphones:
+ Double Tap home screen to turn off screen.
+ Cover proximity sensor to turn on screen.
+ Turn on screen when opening flip cover.
+ Swipe up from center of bottom edge to return hom screen.
For new Samsung Smartphone as S7,S7E android N, Note 7, Galaxy A 2017
+ Double Tap power icon on Always On Display to turn on screen.
This application need to be enabled in Accessibility to use service of system..
It will save battery, support unlock by fingerprint and no Overlay Screen Detected on android M up.