Android - dimming screen from service

Question

I have a service which detects certain system events, like certain hour of the day. I would like my service to (when criteria is met) to dim user screen.

So far, looking though internet and StackOverflow i found a plenty of solutions relying on "getWindow()" which means my app must have a running foreground activity in order to achieve this.

If i just have a service which should put a system-wide screen brightness to, say, 30%, what needs to be done? I don't think it's very similar to changing brightness "locally" (just for my own app).

My idea was obtaining a "window" of current foreground app, but i'm not very sure if that's even possible :\\

Can someone give me some hint or help please, all my searches ended with "you need to call "getWindow()" of your own app"?

Answer 1

I believe it is

System.putInt(contentResolver, System.SCREEN_BRIGHTNESS, brightness)

But you also need permissions Pre api 23

android.permission.WRITE_SETTINGS