1

请我是颤振的初学者，我想在我的应用程序中添加本地化 - 我创建了一个下拉按钮，用户可以使用它来选择一种语言，并且应用程序将被翻译成该特定语言。从下拉按钮中选择一种语言后，我不断收到此错误：

“未找到 MaterialLocalizations。要引入 MaterialLocalizations，请在应用程序的根目录中使用 MaterialApp 来自动包含它们，或者添加一个带有 MaterialLocalizations 委托的本地化小部件。”

我试图将 MaterialApp 移动到我的应用程序的根目录，但我无法在那里实现提供程序。

这是我的 main.dart ：

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import'package:fud_chatapp/controller/language_controller.dart';
import 'package:fud_chatapp/helper/helperfunctions.dart';
import 'package:fud_chatapp/l10n/l10n.dart';
import 'package:fud_chatapp/services/locale_provider.dart';
import 'package:fud_chatapp/services/signin_with_google.dart';
import 'package:fud_chatapp/view/choose_location_time.dart';
import 'package:fud_chatapp/view/home_time.dart';
import 'package:fud_chatapp/view/splashscreen.dart';
import 'package:provider/provider.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';

Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
  (BuildContext context, AsyncSnapshot snapshot) {
return;
};
runApp(MyApp());
}

 class MyApp extends StatefulWidget {
  @override
 State<MyApp> createState() => _MyAppState();
  }

 class _MyAppState extends State<MyApp> {
 bool userIsLoggedIn;

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

getLoggedInState() async {
await HelperFunctions.getUserLoggedInSharedPreference().then((val) {
  setState(() {
    userIsLoggedIn = val;
    });
  });
}

  @override
 Widget build(BuildContext context)=> ChangeNotifierProvider(
 create: (context) => LocaleProvider(),
 builder: (context, child) {
 final provider = Provider.of<LocaleProvider>(context);
  return MaterialApp(
   locale: provider.locale,
   supportedLocales: L10n.all,
    localizationsDelegates: [
     AppLocalizations.delegate,
     GlobalMaterialLocalizations.delegate,
     GlobalCupertinoLocalizations.delegate,
     GlobalWidgetsLocalizations.delegate,
     ],
     routes: {
       //'/': (context) => LoadingPage(),
      '/home': (context) => HomeTime(),
      '/location': (context) => ChooseLocationTime(),
      },
  debugShowCheckedModeBanner: false,
  theme: ThemeData(
    primaryColor: Colors.teal,
    scaffoldBackgroundColor: Color(0xFF404040),
    primarySwatch: Colors.teal,
    visualDensity: VisualDensity.adaptivePlatformDensity,
  ),
  home: SplashScreen(),
  );
 });
}

这是 language_picker_widget.dart ：

import 'package:flutter/material.dart';
import 'package:fud_chatapp/l10n/l10n.dart';
import 'package:fud_chatapp/services/locale_provider.dart';
import 'package:provider/provider.dart';
class LanguagePickerWidget extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
 final provider = Provider.of<LocaleProvider>(context);
final locale = provider.locale ?? Locale('en');

return DropdownButtonHideUnderline(
  child: DropdownButton(
    value: locale,
    icon: Container(width: 12),
    items: L10n.all.map(
          (locale) {
        final flag = L10n.getFlag(locale.languageCode);

        return DropdownMenuItem(
          child: Center(
            child: Text(
              flag,
              style: TextStyle(fontSize: 32),
            ),
          ),
          value: locale,
          onTap: () {
            final provider =
            Provider.of<LocaleProvider>(context, listen: false);

            provider.setLocale(locale);
          },
        );
      },
    ).toList(),
    onChanged: (_) {},
    ),
  );
 }
}

这是我的 appBar 小部件：

class appBarMain extends StatelessWidget implements PreferredSizeWidget 
{
final double barHeight = 50.0;
final String title;
const appBarMain({Key key, this.title}) : super(key: key);

 @override
 Size get preferredSize => Size.fromHeight(kToolbarHeight + barHeight);

   @override
   Widget build(BuildContext context) {
   return AppBar(
   title: SizedBox(
    height: kToolbarHeight,
     child: Image.asset(
      "assets/images/logo.png",
      ),
      ),
      toolbarHeight: kToolbarHeight,
      shape: RoundedRectangleBorder(
      borderRadius: BorderRadius.vertical(bottom: 
      Radius.circular(48.0))),
      actions: [
      LanguagePickerWidget(),
      const SizedBox(width: 12,),
      ],
     backgroundColor: Colors.teal,
     //shape: CustomShapeBorder(),
     centerTitle: true,
     elevation: 0,
     );
    }
    }

这是我的调试控制台：

No MaterialLocalizations found.

_DropdownMenu<Locale> widgets require MaterialLocalizations to be provided by a Localizations 
widget ancestor.
The material library uses Localizations to generate messages, labels, and abbreviations.

To introduce a MaterialLocalizations, either use a MaterialApp at the root of your application 
to include them automatically, or add a Localization widget with a MaterialLocalizations 
delegate.

 The specific widget that could not find a MaterialLocalizations ancestor was: 
_DropdownMenu<Locale>
  dirty
  dependencies: [ScrollConfiguration, _LocalizationsScope-[GlobalKey#1b759], _InheritedTheme]
  state: _DropdownMenuState<Locale>#88cef
  The ancestors of this widget were: 
 : MaterialApp
  state: _MaterialAppState#9cf6a
  : ChangeNotifierProvider<LocaleProvider>
  value: Instance of 'LocaleProvider'
  listening to value
 : MyApp
  state: _MyAppState#0fbda
  ...
  The relevant error-causing widget was: 
     MaterialApp MaterialApp:file:///C:/apps/fud_chatapp/lib/main.dart:54:12
    When the exception was thrown, this was the stack: 
    #0      debugCheckHasMaterialLocalizations.<anonymous closure> 
    (package:flutter/src/material/debug.dart:76:7)
    #1      debugCheckHasMaterialLocalizations (package:flutter/src/material/debug.dart:96:4)
    #2      _DropdownMenuState.build (package:flutter/src/material/dropdown.dart:269:12)
    #3      StatefulElement.build (package:flutter/src/widgets/framework.dart:4782:27)
    #4      ComponentElement.performRebuild 
        (package:flutter/src/widgets/framework.dart:4665:15)
    #5      StatefulElement.performRebuild 
       (package:flutter/src/widgets/framework.dart:4840:11)
    #6      Element.rebuild (package:flutter/src/widgets/framework.dart:4355:5)
    #7      BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2620:33)
    #8      WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:882:21)
    #9      RendererBinding._handlePersistentFrameCallback 
          (package:flutter/src/rendering/binding.dart:319:5)
   #10     SchedulerBinding._invokeFrameCallback 
            (package:flutter/src/scheduler/binding.dart:1143:15)
   #11     SchedulerBinding.handleDrawFrame 
               (package:flutter/src/scheduler/binding.dart:1080:9)
   #12     SchedulerBinding._handleDrawFrame 
                 (package:flutter/src/scheduler/binding.dart:996:5)
   #16     _invoke (dart:ui/hooks.dart:166:10)
   #17     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:270:5)
   #18     _drawFrame (dart:ui/hooks.dart:129:31)
  (elided 3 frames from dart:async)

这是登录页面：

appBar 上带有 LanguagePicker 的登录页面

4

0 回答 0