Flutter: How to set and lock screen orientation on-demand

Question

On one of my flutter pages, I need the screen to set to landscape mode and lock it so it can\'t rotate into portrait mode, but only on the one page. So need a way to enable

Answer 1

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp, DeviceOrientation.portraitDown])
    .then((_) {
      runApp(new MyApp());
    });
}

Answer 2

Sometimes it could not work due to null info about orientation. You can use it simply like this:

import services.dart


void main() {
    SystemChrome.setPreferredOrientations(
    [DeviceOrientation.portraitUp]
     )
        .then((_) {
          runApp(new MyApp());
        });
    }

// wait for settings screen orientation after initiating app and -> then lock orientation

Answer 3

import services.dart and your void main function should be like:

void main(){

    WidgetsFlutterBinding.ensureInitialized();
    SystemChrome.setPreferredOrientations(
       [DeviceOrientation.portraitUp, DeviceOrientation.portraitDown])
       .then((_){
           runApp(MyApp());
       }
    );
}

Answer 4

I would use a simple mixin to lock phone in portrait. The following solution locks the entire app in portrait or sets specific screens to portrait while keeping rotation elsewere.

import 'package:flutter/cupertino.dart';
import 'package:flutter/services.dart';

/// Forces portrait-only mode application-wide
/// Use this Mixin on the main app widget i.e. app.dart
/// Flutter's 'App' has to extend Stateless widget.
///
/// Call `super.build(context)` in the main build() method
/// to enable portrait only mode
mixin PortraitModeMixin on StatelessWidget {
  @override
  Widget build(BuildContext context) {
    _portraitModeOnly();
    return null;
  }
}

/// Forces portrait-only mode on a specific screen
/// Use this Mixin in the specific screen you want to
/// block to portrait only mode.
///
/// Call `super.build(context)` in the State's build() method
/// and `super.dispose();` in the State's dispose() method
mixin PortraitStatefulModeMixin<T extends StatefulWidget> on State<T> {
  @override
  Widget build(BuildContext context) {
    _portraitModeOnly();
    return null;
  }

  @override
  void dispose() {
    _enableRotation();
  }
}

/// blocks rotation; sets orientation to: portrait
void _portraitModeOnly() {
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);
}

void _enableRotation() {
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
    DeviceOrientation.landscapeLeft,
    DeviceOrientation.landscapeRight,
  ]);
}

To block rotation in the entire app implement PortraitModeMixin in the main App widget. Remember to call super.build(context) in Widget build(BuildContext context) method.

/// Main App widget
class App extends StatelessWidget with PortraitModeMixin {
  const App();

  @override
  Widget build(BuildContext context) {
    super.build(context);
    return CupertinoApp(
      title: 'Flutter Demo',
      theme: CupertinoThemeData(),
      home: Text("Block screen rotation example"),
    );
  }
}

To block rotation in a specific screen implement PortraitStatefulModeMixin<SampleScreen> in the specific screen's state. Remember to call super.build(context) in the State's build() method and super.dispose() in dispose() method. If your screen is a StatelessWidget - simply repeat the App's solution (previous example) i.e. use PortraitModeMixin.

/// Specific screen
class SampleScreen extends StatefulWidget {
  SampleScreen() : super();

  @override
  State<StatefulWidget> createState() => _SampleScreenState();
}

class _SampleScreenState extends State<SampleScreen>
    with PortraitStatefulModeMixin<SampleScreen> {
  @override
  Widget build(BuildContext context) {
    super.build(context);
    return Text("Flutter - Block screen rotation example");
  }

  @override
  void dispose() {
     super.dispose();
  }
}

Mixins with such syntax work from Dart 2.1

Answer 5

First import the services package:

import 'package:flutter/services.dart';

This will give you access to the SystemChrome class, which "Controls specific aspects of the operating system's graphical interface and how it interacts with the application."

When you load the Widget, do something like this:

@override
void initState(){
  super.initState();
  SystemChrome.setPreferredOrientations([
      DeviceOrientation.landscapeRight,
      DeviceOrientation.landscapeLeft,
  ]);
}

then when I leave the page, put it back to normal like this:

@override
dispose(){
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.landscapeRight,
    DeviceOrientation.landscapeLeft,
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);
  super.dispose();
}

Answer 6

You can use orientation_helper for this https://pub.dev/packages/orientation_helper . It’s main goal is to set orientation for each screen in an app.