In Android smartphones, you have to press the power key for a short time to lock or unlock the device. A long press of the power key could show you the power off menu. But why wear out the power key by locking and unlocking the phone when you can do this all using a simple app called KnockOn. This app allows you to double-tap on the phone screen to unlock it and double-tap on the home screen to lock it once again.
The KnockOn app is designed with a minimal and simple interface. It opens up with four rectangular section, tapping on which you can start the app or change its settings. In the app settings, you can define if you want to be able to lock the phone or you want the ability to wake up the phone from a locked state. In other words whether you want the tap to lock feature or the tap to unlock feature too. In the Pro (paid) version of the app, you can also choose the sleep time and the tap speed for all these operations.
Since the app is able to control your phone’s screen, it requires administrator level access. The app must be activate as the device administrator before you can use it to lock or unlock the phone. Once these settings have been saved, you can proceed to the home screen and double-tap to lock the phone and turn off the screen. Double-tapping on a locked phone’s turned off screen will wake it up. And double-tapping on the lock-screen itself will turn off the screen.
Conclusion: The KnockOn app is great for the large screen phones where it is a little inconvenient to press the power key or if you do not want to press the power key over and over again to make it last longer.
You can get the KnockOn app for Android from https://play.google.com/store/apps/details?id=com.jamworks.knockz.