From the same SO post,it mentioned that the screen plugin encountered some issues. I've checked the plugin and it seems that it was not updated since March 13, 2019. Another plugin that would give the same function you needed is wakelock plugin. It is still available currently maintained by the author. In fact, latest version 0.5.0+2 was release last March 7, 2021.
Hi, I am still maintaining it :) We recently added macOS support as
well Also, Flutter is open source - they have first-party plugins,
however, they do say themselves that they will abandon their
first-party solutions if a better third party project exists. So why
would they want to create one for something that works perfectly fine?
– creativecreatorormaybenot Feb 8 at 16:17
I've tested the sample given in the wakelock package:
import 'package:flutter/material.dart';
import 'package:wakelock/wakelock.dart';
void main() {
runApp(WakelockExampleApp());
}
class WakelockExampleApp extends StatefulWidget {
@override
_WakelockExampleAppState createState() => _WakelockExampleAppState();
}
class _WakelockExampleAppState extends State<WakelockExampleApp> {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Wakelock example app'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
const Spacer(
flex: 3,
),
OutlinedButton(
onPressed: () {
setState(() {
Wakelock.enable();
});
},
child: const Text('enable wakelock'),
),
const Spacer(),
OutlinedButton(
onPressed: () {
setState(() {
Wakelock.disable();
});
},
child: const Text('disable wakelock'),
),
const Spacer(
flex: 2,
),
FutureBuilder(
future: Wakelock.enabled,
builder: (context, AsyncSnapshot<bool> snapshot) {
final data = snapshot.data;
if (data == null) {
return Container();
}
return Text('The wakelock is currently '
'${data ? 'enabled' : 'disabled'}.');
},
),
const Spacer(
flex: 3,
),
],
),
),
),
);
}
}
Here is the output in Android:

Output in iOS:

Also, it seems that you've resolved the previous issue in your code. It would be nice to share a minimal, complete and verifiable example for the community to understand the issue very well.