标签: flutter2.0

运行Flutter项目后，出现此错误。我能做什么来解决它？

Error: The method 'setMockMessageHandler' 
isn't defined for the class 'BasicMessageChannel<dynamic>'.

FAILURE: Build failed with an exception.

迁移到 null-safety 和 flutter 2 后，我遇到了 ios 构建问题：
我运行flutter clean; rm ios/Podfile.lock pubspec.lock; rm -rf ios/Pods ios/Runner.xcworkspace; flutter run --flavor dev -t lib/main_dev.dart

并得到这个 logcat：

    Undefined symbols for architecture arm64:
      "_OBJC_CLASS_$_FlutterStandardTypedData", referenced from:
          objc-class-ref in google_maps_flutter(GoogleMapController.o)
      "_OBJC_CLASS_$_FlutterStandardMessageCodec", referenced from:
          objc-class-ref in google_maps_flutter(GoogleMapController.o)
      "_OBJC_CLASS_$_FlutterError", referenced from:
          objc-class-ref in firebase_core(FLTFirebasePlugin.o)
          objc-class-ref in google_maps_flutter(FLTGoogleMapsPlugin.o)
          objc-class-ref in google_maps_flutter(FLTGoogleMapTileOverlayController.o)
          objc-class-ref in google_maps_flutter(GoogleMapMarkerController.o)
          objc-class-ref in google_maps_flutter(GoogleMapController.o)
          objc-class-ref in onesignal_flutter(OSFlutterCategories.o)
      "_OBJC_CLASS_$_FlutterMethodChannel", referenced from:
          objc-class-ref in firebase_core(FLTFirebaseCorePlugin.o)
          objc-class-ref in firebase_crashlytics(FLTFirebaseCrashlyticsPlugin.o)
          objc-class-ref in google_maps_flutter(GoogleMapController.o)
          objc-class-ref in onesignal_flutter(OSFlutterOutcomeEventsController.o)
          objc-class-ref …

我正在制作一个项目，其中当用户单击按钮时，计时器将启动，在用户设置时间后，将播放我 just_audio: ^0.6.15+1 在我的 flutter 项目中使用的声音，但它会导致下面的许多问题都是错误的。

D/Linux   (21303): [Posix_connect Debug]Process com.snss.xlnc :443 \nE/flutter (21303): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Connection aborted\nE/flutter (21303): #0      AudioPlayer._load (package:just_audio/just_audio.dart:688:11)\nE/flutter (21303): <asynchronous suspension>\nE/flutter (21303): #1      AudioPlayer.load (package:just_audio/just_audio.dart:625:14)\nE/flutter (21303): <asynchronous suspension>\nE/flutter (21303): #2      AudioPlayer.setAudioSource (package:just_audio/just_audio.dart:602:18)\nE/flutter (21303): <asynchronous suspension>\nE/flutter (21303): #3      _ClassStartState.keepRunning (package:xlnc/tutor/startClass.dart:84:7)\nE/flutter (21303): <asynchronous suspension>\nE/flutter (21303): \n

这是我的代码

var t = DateFormat.Hms().parse(time);\nvar rT = DateFormat.Hms().parse(remTime);\nvar co = t.isAfter(rT);\n\nif (co) {\n  player.setUrl('$soundUrl');\n  player.setVolume(1);\n  player.play();\n  player.setLoopMode(LoopMode.one);\n}\n

这是我的颤振医生-v

[\xe2\x88\x9a] Flutter (Channel stable, 2.0.1, on Microsoft Windows …

我发布这个问题是为了帮助未来的读者。升级到后，Flutter 2.8在尝试运行我的应用程序时突然出现此错误：

Flutter: A value of type 'ListTileThemeData' can't be assigned to a variable of type 'ListTileTheme'.

我是如何解决这个问题的？

在我的应用程序中，我使用 2 个材质应用程序来处理底部导航栏的导航。由于我的应用程序非常复杂，这是执行此操作的最佳方法。

在一个屏幕上，当用户未登录时，将打开一个底部表单，用户可以在其中输入他的登录凭据。

bottomSheet 应出现在导航栏上方。

在下面的代码片段中，这就是我解决它的方法。

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(),
    );
  }
}

final _navigationKey = GlobalKey<NavigatorState>();

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int currentIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      resizeToAvoidBottomInset: true,
      body: MaterialApp(
        navigatorKey: _navigationKey, …

我在 Flutter 2.0 中遇到了 Firebase Cloud Messaging onMessage 的问题。

功能

FirebaseMessaging.onMessage.listen((RemoteMessage message) { ... }

是不叫在前台接收消息时。但是，日志说

收到消息的广播

在收到的第一条消息中，我收到了额外的警告，例如：

访问隐藏方法 Landroid/os/WorkSource

但是警告在后续消息中消失。

在有趣的是，

FirebaseMessaging.onBackgroundMessage(firebaseMessagingBackgroundHandler);

作品。

如果我将应用程序发送到后台，我会收到通知并调用定义的方法。

代码

@override
void initState() {
    initializeFlutterFire()
        .then((value) => subscribeToMessages);

    super.initState();
}

Future<void> initializeFlutterFire() async {
    try {
        Firebase.initializeApp();
        setState(() {
            _initialized = true;
            print("Firebase has been initialized");
        });
    } catch (e) {
       setState(() {
           _error = true;
       });
    }
}

void subscribeToMessages() {
    // The following handler is called, when App …

我正在使用 Flutter 2.0 开发一个 Windows 桌面应用程序。如何清除应用程序数据并使其保持在第 0 天的状态、删除所有缓存、删除任何签名帐户……就像 Android 中的清除数据一样。

我不能使用，TextEditingController因为TextFormField使用Autocomplete fieldViewBuilder TextEditingController

Autocomplete(
                optionsBuilder: (TextEditingValue textEditingValue) {
                  if (textEditingValue.text == '') return [];

                  return this
                      .productNames
                      .where((Map<String, dynamic> option) {
                    return option['ar']
                        .toLowerCase()
                        .contains(textEditingValue.text.toLowerCase());
                  });
                },
                fieldViewBuilder: (context, textEditingController,
                        focusNode, onFieldSubmitted) =>
                    TextFormField(                             
                  controller: textEditingController,//uses fieldViewBuilder TextEditingController
                   focusNode: focusNode,
                ),
              ),

Flutter 应用程序专为移动和 Web 设计。我们使用 firebase_messaging 来实现消息传递功能。早些时候这是工作魅力。最近我们将 Flutter SDK 升级到 2.0 版本（Channel stable，2.0.4）。

该应用程序的工作方式与早期的移动版本相同。但是在网络版本中执行时出现下面提到的错误并且无法解决。

以下命令已尝试禁用空安全，但没有用。

flutter run --no-sound-null-safety\n

\n

错误日志：

\n

Debug service listening on ws://127.0.0.1:53789/y22KqzTNKwU=/ws\n\nRunning with unsound null safety\nFor more information see https://dart.dev/null-safety/unsound-null-safety\nDebug service listening on ws://127.0.0.1:53789/y22KqzTNKwU=/ws\nTypeError: Cannot read property 'isSupported' of undefined\n    at new firebase_messaging_web.FirebaseMessagingWeb.new (http://localhost:53495/packages/firebase_messaging_web/firebase_messaging_web.dart.lib.js:189:51)\n    at Function.registerWith (http://localhost:53495/packages/firebase_messaging_web/firebase_messaging_web.dart.lib.js:56:73)\n    at Object.registerPlugins (http://localhost:53495/packages/pca_app/generated_plugin_registrant.dart.lib.js:44:49)\n    at main (http://localhost:53495/web_entrypoint.dart.lib.js:44:35)\n    at main.next (<anonymous>)\n    at runBody (http://localhost:53495/dart_sdk.js:39051:34)\n    at Object._async [as async] (http://localhost:53495/dart_sdk.js:39082:7)\n    at main$ (http://localhost:53495/web_entrypoint.dart.lib.js:43:18)\n    at http://localhost:53495/main_module.bootstrap.js:19:10\n    at Array.forEach (<anonymous>)\n …

在切换到 Flutter 2 之前，我使用旧版本的 firebaseMessaging 没有问题，现在我有了最新版本。升级后出现以下错误：

The class 'FirebaseMessaging' doesn't have a default constructor.

和：

The method 'configure' isn't defined for the type 'FirebaseMessaging'.

全班：

class ShowNotifications {
static final FirebaseMessaging firebaseMessaging = FirebaseMessaging();
 static FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
  new FlutterLocalNotificationsPlugin();

  static void initialization(){
    var initializationSettingsAndroid =
    new AndroidInitializationSettings('@mipmap/ic_launcher');
    var initializationSettingsIOS = new IOSInitializationSettings();
    var initializationSettings = new InitializationSettings(
        android: initializationSettingsAndroid, iOS: initializationSettingsIOS);

    flutterLocalNotificationsPlugin = new FlutterLocalNotificationsPlugin();
    flutterLocalNotificationsPlugin.initialize(initializationSettings,
        onSelectNotification: onSelectNotification);
  }




 static void showNotification(String title, String body) async {
    await _demoNotification(title, …