Screen locker allows you to hide to lock your screen in many different ways.

It works without root on android p but offers a couple of alternative ways to lock the screen on previous versions.

Tasker Support
You can easily lock the screen from tasker.

Automation Apps Support
You can send broadcasts to "Screen Locker" with your favorite automation apps like tasker to lock the screen.

Shortcuts
You can place a shortcut on your home screen to lock the screen from your home screen.

Xposed
If you have the xposed framework installed you can lock the screen by double tapping on the status bar or on the keyguard.

Quick Settings Tile
There's a handy quick settings tile to lock the screen from your quick settings.

App Drawer Icon
There's a option place a icon on your launcher to lock the screen.

If you have any feature requests send me an email or write post in the Google+ community.

This app uses the BIND_DEVICE_ADMIN permission to lock your screen while you set the mode to device admin.

Links:

Google+ community:
https://plus.google.com/communities/113541230929934872757