用Flutter固定屏幕方向

发表于 2020年05月30日
flutter

以下为我用Flutter固定屏幕方向，也称Flutter禁止横屏坚屏的方法。

目录表

静态方法Flutter固定屏幕方向

导包

import 'package:flutter/services.dart';

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

支持横坚屏切换

SystemChrome.setPreferredOrientations(
      [DeviceOrientation.portraitUp, DeviceOrientation.portraitDown]);

1 2	SystemChrome.setPreferredOrientations( [DeviceOrientation.portraitUp, DeviceOrientation.portraitDown]);

全局设置

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

SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp, DeviceOrientation.portraitDown])

.then((_) {

runApp(new MyApp());

});

很可能会出现这个错误：

E/flutter (12370): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.
E/flutter (12370): If you're running an application and need to access the binary messenger before `runApp()` has been called (for example, during plugin initialization), then you need to explicitly call the `WidgetsFlutterBinding.ensureInitialized()` first.
E/flutter (12370): If you're running a test, you can call the `TestWidgetsFlutterBinding.ensureInitialized()` as the first line in your test's `main()` method to initialize the binding.

E/flutter (12370): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.

E/flutter (12370): If you're running an application and need to access the binary messenger before `runApp()` has been called (for example, during plugin initialization), then you need to explicitly call the `WidgetsFlutterBinding.ensureInitialized()` first.

E/flutter (12370): If you're running a test, you can call the `TestWidgetsFlutterBinding.ensureInitialized()` as the first line in your test's `main()` method to initialize the binding.

在main()中进行异步处理时，应编写以下代码

WidgetsFlutterBinding.ensureInitialized();

1	WidgetsFlutterBinding.ensureInitialized();

Flutter禁止横屏

标准示例main.dart

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