This plugin disables automatic screen off and prevents the screen from turning off.

Add this to your package's pubspec.yaml file:

dependencies:
  keep_screen_on: ^2.1.0

Import KeepScreenOn.

import 'package:keep_screen_on/keep_screen_on.dart';

To keep the screen from turning off, call the turnOn method of the KeepScreenOn class.

// Keep the screen on.
KeepScreenOn.turnOn();

Calling the turnOff method of the KeepScreenOn class will restore the screen to turn off automatically.
Alternatively, you can do the same by specifying false as the argument to the turnOn method.

// Reset
KeepScreenOn.turnOff();

// or...
KeepScreenOn.turnOn(false);

You can check if the screen is not turned off by checking the isOn property or isOff property.
Since isOn and isOff return Future , you need to use "await" or receive the value with the "then" method.

Future<bool> getScreenKeepOn() async {
  return await KeepScreenOn.isOn; 
}

Future<bool> getScreenKeepOff() async {
  return await KeepScreenOn.isOff;
}

When you call the turnOn method with no arguments or with true,
Android sets android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON for the activity window as an internal action.
iOS sets UIApplication.shared.isIdleTimerDisabled to true.

For this reason, be sure to use the dispose method of StatefulWidget etc.

KeepScreenOn.turnOff();

Should be called. If you forget to call turnOff (or turnOn(false)), the screen will not turn off automatically while the app is running.

For Android, when the activity is switched, the automatic screen off will follow the activity to which it was switched.
For iOS, automatic screen off is restored when you move to the background.