无法在 Flutter 中更改方向答案

【问题标题】：Not able to change orientation in Flutter无法在 Flutter 中更改方向
【发布时间】：2020-02-18 04:42:34
【问题描述】：

使用下面的代码后，我无法将方向更改为横向模式。我在处置时也将方向恢复正常。

我想要做的是，我希望一个特定的活动在 android 和 IOS 上都是纵向的，而其他活动是正常的（纵向和横向）

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

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

【问题讨论】：

尝试在 dispose 方法中像这样调用。 SystemChrome.setPreferredOrientations([ ]);

标签： flutter orientation

【解决方案1】：

尝试使用 dart pub 上提供的这个颤振包：

https://pub.dev/packages/auto_orientation#-readme-tab-

【讨论】：

【解决方案2】：

你可以使用包https://pub.dev/packages/auto_orientation

代码sn-p

FlatButton(
        onPressed: () {
          AutoOrientation.portraitDownMode();
        }

完整示例代码

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

void main() {
  runApp(
    AutoOrientationDemo(),
  );
}

class AutoOrientationDemo extends StatefulWidget {
  AutoOrientationDemo({this.title = 'Auto Orientation Demo'});

  final String title;

  @override
  State<StatefulWidget> createState() {
    return _AutoOrientationDemoState();
  }
}

class _AutoOrientationDemoState extends State<AutoOrientationDemo> {
  TargetPlatform _platform;

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: widget.title,
      theme: ThemeData.light().copyWith(
        platform: _platform ?? Theme.of(context).platform,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Column(
          children: <Widget>[
            Row(
              children: <Widget>[
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.portraitDownMode();
                    },
                    child: Padding(
                      child: Text("Portrait UPSIDE Down"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.fullAutoMode();
                    },
                    child: Padding(
                      child: Text("All modes"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
              ],
            ),

            Row(
              children: <Widget>[
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.landscapeAutoMode();
                    },
                    child: Padding(
                      child: Text("Landscape auto"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.portraitAutoMode();
                    },
                    child: Padding(
                      child: Text("Portrait auto"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
              ],
            ),

            Row(
              children: <Widget>[
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.landscapeLeftMode();
                    },
                    child: Padding(
                      child: Text("Landscape left mode"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      SystemChrome.setPreferredOrientations([
                        DeviceOrientation.portraitUp,
                        DeviceOrientation.portraitDown,
                        DeviceOrientation.landscapeLeft,
                        DeviceOrientation.landscapeRight,
                      ]);
                      AutoOrientation.landscapeRightMode();
                    },
                    child: Padding(
                      child: Text("Landscape right mode"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
              ],
            ),
            Row(
              children: <Widget>[
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.portraitUpMode();
                    },
                    child: Padding(
                      child: Text("Portrait up mode"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
                Expanded(
                  child: FlatButton(
                    onPressed: () {
                      AutoOrientation.portraitDownMode();
                    },
                    child: Padding(
                      child: Text("Portrait down mode"),
                      padding: EdgeInsets.symmetric(vertical: 16.0),
                    ),
                  ),
                ),
              ],
            )
          ],
        ),
      ),
    );
  }
}

示例演示

【讨论】：