Screen orientation/Auto 在 Flutter 应用程序中仅在一个屏幕上旋转

Question

我只想在我的应用程序的一个屏幕上应用屏幕方向。我尝试使用 if condition and orientation builder 来应用它，但不知何故，它不起作用。例如，如果用户按下自动旋转按钮，屏幕应该根据旋转进行操作，但我只想在一个屏幕上显示。

//main.dart

           void main(
           {
           WidgetsFlutterBinding.ensureInitialized();        
           SystemChrome.setPreferredOrientations
           ([DeviceOrientation.portraitUp]);
            runApp(IframeScreen());
            }






                  import 'dart:async';
                  import 'package:flutter/material.dart';
                  import 'package:permission_handler/permission_handler.dart';
                  import 'package:flutter_inappwebview/flutter_inappwebview.dart';
                  import 'package:flutter/services.dart';
                  import 'package:modal_progress_hud/modal_progress_hud.dart';
                  import 'package:provider/provider.dart';

                 class IframeScreen extends StatefulWidget {
                  @override
                 _IframeScreenState createState() => _IframeScreenState();
                  }

                 class _IframeScreenState extends State<IframeScreen> {

                  InAppWebViewController _webViewController;

                  IframeScreen iframe = new IframeScreen();

                  _IframeScreenState(
  
                   @override
                   void initState() {
                   onLoadingTesting().then((value) {
                   print('check modalprogress');


                 });

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

            InAppWebView webViewMethod() {
            WidgetsFlutterBinding.ensureInitialized();
            Permission.camera.request();
            Permission.microphone.request();
           }
          }

           @override
           Widget build(BuildContext context) {
           return ModalProgressHUD(
  inAsyncCall: _saving,
  child: WillPopScope(
    onWillPop: (){
      if(MediaQuery.of(context).orientation==Orientation.landscape){
        SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);
      }

      return Future.value(true);
    },
    child: Scaffold(
      body:  OrientationBuilder(
        builder: (BuildContext context,orientation) {
          return Column(
            children: <Widget>[
              Expanded(
                child: Container(
                  child: InAppWebView(
                      initialUrl:
                      "https://appr.tc/r/158489234",
                      initialOptions: InAppWebViewGroupOptions(
                        crossPlatform: InAppWebViewOptions(
                          mediaPlaybackRequiresUserGesture: false,
                          debuggingEnabled: true,
                        ),
                      ),
                      onWebViewCreated: (
                          InAppWebViewController controller) {
                        _webViewController = controller;
                      },
                      androidOnPermissionRequest:
                          (InAppWebViewController controller, String origin,
                          List<String> resources) async {
                        return PermissionRequestResponse(
                            resources: resources,
                            action: PermissionRequestResponseAction.GRANT);
                      }),
                ),
              )
            ],

          );
        }
      )

    ),
  ),
);

}

Answer 1

为此，您应该在 main() 方法中设置首选方向，如

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

这将确保您的应用将纵向显示（如本示例代码中所设置），直到您更改它。

这里的一个建议是，在你需要横向的屏幕中，不要在Dispose函数中改变方向，而是用“WillPopScope”包裹脚手架，并实现OnWillPop()方法如下

onWillPop: () {
    if (MediaQuery.of(context).orientation == Orientation.landscape) {
      SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp, DeviceOrientation.portraitDown]);
    }
    return Future.value(true);
  },

这将使从横向屏幕到纵向屏幕的过渡更加平滑。

干杯！

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