Android: How to turn screen on and off programmatically?

Question

Before marking this post as a \"duplicate\", I am writing this post because no other post holds the solution to the problem.

I am trying to turn off the device, then

Answer 1

To keep screen on:

getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

Back to screen default mode: just clear the flag FLAG_KEEP_SCREEN_ON

getWindow().clearFlags(android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);