flutter - setState() 或 markNeedsBuild() 在构建期间调用，使用 FutureBuilder 中的 Provider 和 Flutter 中的 StreamBuilder

问题描述

我有以下问题。当我的应用程序启动（用户登录）时，我需要从 firebase 读取值accountId- 这是与用户帐户分开创建的帐户的 ID，该帐户存储在 Firestore 文档之一中。accountId通过嵌套的 FutureBuilder获取后main.dart，我将其保存通过

Provider.of<RegistrationHelper>(context.updateAccountId(accountId);

到我的班级RegistrationHelper，使其可用于其他地方。

问题是，虽然accountId保存在中RegistrationHelper，但我收到以下错误，您可以在底部找到。这是我的代码main.dart。有谁知道如何解决这个问题？非常感谢您的支持！

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(JustAnApp());
}

class EmotionsApp extends StatelessWidget {
  final Future<FirebaseApp> _initialization = Firebase.initializeApp();

  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider<RegistrationHelper>(
          create: (_) => RegistrationHelper(),
        ),
        ChangeNotifierProvider<EmotionsHelper>(
          create: (_) => EmotionsHelper(),
        ),
      ],
      child: MaterialApp(
        title: 'Jak się dziś czujesz?',
        theme: ThemeData(
          primarySwatch: Colors.purple,
          accentColor: Colors.orange,
          accentColorBrightness: Brightness.light,
          canvasColor: Color.fromRGBO(255, 254, 229, 1),
          backgroundColor: Colors.deepPurple,
          buttonTheme: ButtonTheme.of(context).copyWith(
            buttonColor: Colors.purple,
            textTheme: ButtonTextTheme.primary,
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(20),
            ),
          ),
          fontFamily: 'Raleway',
          textTheme: ThemeData.light().textTheme.copyWith(
                bodyText1: TextStyle(
                  color: Color.fromRGBO(20, 51, 51, 1),
                ),
                bodyText2: TextStyle(
                  color: Color.fromRGBO(20, 51, 51, 1),
                ),
                headline1: TextStyle(
                  fontSize: 20,
                  fontFamily: 'RobotoCondensed',
                  fontWeight: FontWeight.bold,
                ),
              ),
        ),
        home: FutureBuilder(
          future: _initialization,
          builder: (context, snapshot) {
            if (snapshot.hasError) {
              print('Snapshot error (main.dart) : ${snapshot.error}');
              return SomethingWentWrong();
            }
            if (snapshot.connectionState == ConnectionState.waiting) {
              return Center(child: CircularProgressIndicator());
            }

            if (snapshot.connectionState == ConnectionState.done) {
              // print('Snapshot (main.dart) : ${snapshot.connectionState}');
              return StreamBuilder(
                  stream: FirebaseAuth.instance.authStateChanges(),
                  builder: (context, streamSnapshot) {
                    if (streamSnapshot.data == null) return LoginScreen();

                    if (streamSnapshot.connectionState ==
                        ConnectionState.waiting)
                      return Center(
                        child: CircularProgressIndicator(),
                      );

                    if (streamSnapshot.hasData) {
                      //print('MAIN.DART streamSnapshot data: $streamSnapshot');
                      final user = FirebaseAuth.instance.currentUser;

                      return FutureBuilder(
//HERE IS WHERE I AM FETCHING ACCOUNT ID
                          future: FirebaseFirestore.instance
                              .collection('root')
                              .doc('users')
                              .collection('userData')
                              .doc(user!.uid)
                              .get(),
                          builder: (BuildContext context, AsyncSnapshot snap) {
                            if (snap.data == null)
                              return Center(child: CircularProgressIndicator());

                            if (snap.connectionState == ConnectionState.waiting)
                              return Center(
                                child: CircularProgressIndicator(),
                              );

                            if (snap.hasData) {
//AND HERE I AM STORING ACCOUNT ID TO REGISTRATION HELPER CLASS

                              Provider.of<RegistrationHelper>(context)
                                  .updateActualAccountId(
                                      snap.data['accountId']);

                              //return Text('accountId updated');
                            }
                            return FacilitiesScreen();
                          });
                    } else {
                      return LoginScreen();
                    }
                  });
            }
            return Center(child: CircularProgressIndicator());
          },
        ),
        routes: {
          ...
        },
      ),
    );
  }
}

以及 RegistrationHelper 中的一个简单方法：

 void updateActualAccountId(String accountId) {
    actualAccountId = accountId;
    notifyListeners();
  }

我得到的错误：

    ======== Exception caught by foundation library ====================================================
The following assertion was thrown while dispatching notifications for RegistrationHelper:
setState() or markNeedsBuild() called during build.

This _InheritedProviderScope<RegistrationHelper> widget cannot be marked as needing to build because the framework is already in the process of building widgets.  A widget can be marked as needing to be built during the build phase only if one of its ancestors is currently building. This exception is allowed because the framework builds parent widgets before children, which means a dirty descendant will always be built. Otherwise, the framework might not visit this widget during this build phase.
The widget on which setState() or markNeedsBuild() was called was: _InheritedProviderScope<RegistrationHelper>
  value: Instance of 'RegistrationHelper'
  listening to value
The widget which was currently being built when the offending call was made was: FutureBuilder<DocumentSnapshot<Map<String, dynamic>>>
  dirty
  state: _FutureBuilderState<DocumentSnapshot<Map<String, dynamic>>>#bdfb1
When the exception was thrown, this was the stack: 
#0      Element.markNeedsBuild.<anonymous closure> (package:flutter/src/widgets/framework.dart:4305:11)
#1      Element.markNeedsBuild (package:flutter/src/widgets/framework.dart:4320:6)
#2      _InheritedProviderScopeElement.markNeedsNotifyDependents (package:provider/src/inherited_provider.dart:531:5)
#3      ChangeNotifier.notifyListeners (package:flutter/src/foundation/change_notifier.dart:308:24)
#4      RegistrationHelper.updateActualAccountId (package:emotions4_flutter/auth/auth_registration_helper.dart:42:5)
#5      _FacilitiesScreenState._updateAccountId (package:emotions4_flutter/screens/facilities_screen.dart:27:10)
#6      _FacilitiesScreenState.build.<anonymous closure> (package:emotions4_flutter/screens/facilities_screen.dart:101:25)
#7      _FutureBuilderState.build (package:flutter/src/widgets/async.dart:782:55)
#8      StatefulElement.build (package:flutter/src/widgets/framework.dart:4782:27)
#9      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4665:15)
#10     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4840:11)
#11     Element.rebuild (package:flutter/src/widgets/framework.dart:4355:5)
#12     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2620:33)
#13     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:882:21)
#14     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:319:5)
#15     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1143:15)
#16     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1080:9)
#17     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:996:5)
#21     _invoke (dart:ui/hooks.dart:166:10)
#22     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:270:5)
#23     _drawFrame (dart:ui/hooks.dart:129:31)
(elided 3 frames from dart:async)
The RegistrationHelper sending notification was: Instance of 'RegistrationHelper'
====================================================================================================

标签： flutterdartgoogle-cloud-firestoreflutter-providerflutter-futurebuilder

flutter - setState() 或 markNeedsBuild() 在构建期间调用，使用 FutureBuilder 中的 Provider 和 Flutter 中的 StreamBuilder

问题描述

解决方案

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