'颤振肘错误：未处理的异常：坏 state：在旋转设备时调用关闭后无法发出新状态'

Question

我收到 Flutter 肘错误：未处理的异常：错误 state：在旋转设备时调用关闭后无法发出新状态。 是否有可能是因为 flutter 在设备旋转时重建 state，关闭肘关节？ 我正在使用 get_it 来注入依赖项。

serviceLocator.dart

/// [USER MANAGEMENT]
  ///
  // [User Management page Cubit]
  featureServiceLocator.registerLazySingleton<UserManagementCubit>(() =>
      UserManagementCubit(userManagementUseCase: featureServiceLocator()));

用户管理.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:popup_card/popup_card.dart';

import '../../../../core/const/colors.dart';
import '../../../../core/const/fonts.dart';
import '../../../../core/widgets/custom.textfield.dart';
import '../../../../core/widgets/error.message.box.dart';
import '../../../../core/widgets/page.title.dart';
import '../../../../injection.containers/features.injector.dart';
import '../../domain/entity/user.list.entity.dart';
import '../cubit/user.management.cubit.dart';
import 'add.user.popup.card.dart';
import 'user.detail.card.dart';

class UserManagementPage extends StatefulWidget {
  const UserManagementPage({Key? key}) : super(key: key);

  @override
  State<UserManagementPage> createState() => _UserManagementPageState();
}

final TextEditingController _searchController = TextEditingController();

class _UserManagementPageState extends State<UserManagementPage> {
  @override
  void initState() {
    _call();
    super.initState();
  }

  Future<void> _call() async {
    await featureServiceLocator<UserManagementCubit>().fetchUsersList();
  }

  
  UsersListEntity? _usersListEntity;

  @override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;

    return Scaffold(
      floatingActionButton: PopupItemLauncher(
        tag: 'test',
        child: Material(
          color: primarycolor,
          elevation: 2,
          shape:
              RoundedRectangleBorder(borderRadius: BorderRadius.circular(32)),
          child: const Icon(
            Icons.add_rounded,
            color: Colors.white,
            size: 50,
          ),
        ),
        popUp: PopUpItem(
          padding: const EdgeInsets.all(1),
          color: Colors.white,
          shape:
              RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
          elevation: 0,
          tag: 'test',
          child: const AddUserPopUpCard(),
        ),
      ),
      body: Padding(
        padding: const EdgeInsets.fromLTRB(20, 20, 20, 0),
        child: CustomScrollView(
          physics: const BouncingScrollPhysics(),
          slivers: <Widget>[
            const PageTitle(
                title: "User Management", subtitle: "Add or remove users"),
            SliverToBoxAdapter(
              child: Padding(
                padding: const EdgeInsets.only(left: 20, right: 20, top: 40),
                child: Wrap(
                  alignment: WrapAlignment.spaceBetween,
                  direction: Axis.horizontal,
                  runSpacing: 5,
                  children: [
                    SizedBox(
                      width: size.width,
                      child: CustomTextField(
                        icon: Icons.search,
                        onChange: (_) {
                          featureServiceLocator<UserManagementCubit>()
                              .searchUser(
                                  username: _searchController.text,
                                  users: _usersListEntity!);
                        },
                        controller: _searchController,
                        hintText: "search user",
                      ),
                    ),
                  ],
                ),
              ),
            ),
            SliverToBoxAdapter(
              child: Padding(
                padding: EdgeInsets.only(
                    left: size.width * 0.06, right: size.width * 0.06, top: 30),
                child: Wrap(
                  alignment: WrapAlignment.spaceBetween,
                  direction: Axis.horizontal,
                  children: [
                    _listTitle("Name"),
                    _listTitle("Role"),
                    Wrap(
                      crossAxisAlignment: WrapCrossAlignment.center,
                      children: [
                        _listTitle("Salary"),
                        InkWell(
                          child: const Icon(Icons.arrow_drop_down),
                          onTap: () {},
                        )
                      ],
                    ),
                    _listTitle("Action")
                  ],
                ),
              ),
            ),
            const SliverToBoxAdapter(
              child: Padding(
                padding: EdgeInsets.fromLTRB(40, 5, 40, 5),
                child: Divider(),
              ),
            ),
            _bodyStateManagement(size),
          ],
        ),
      ),
    );
  }

  /// State management
  ///
  /// cubit: [UserManagementCubit]
  ///

  BlocProvider<UserManagementCubit> _bodyStateManagement(Size size) {
    return BlocProvider<UserManagementCubit>(
      create: (context) =>
          featureServiceLocator<UserManagementCubit>(),
      child: BlocBuilder<UserManagementCubit, UserManagementState>(
        builder: (context, state) {
          if (state is UserManagementInitial) {
            return const SliverToBoxAdapter(
                child: Center(child: CupertinoActivityIndicator()));
          } else if (state is UserManagementLoadNetworkFailureState) {
            ///
            /// [UserManagementLoadNetworkFailureState]
            ///
            return SliverToBoxAdapter(
                child: Center(
              child: Text("No internet connection", style: menuFont),
            ));
          } else if (state is UserManagementLoadServerFailureState) {
            ///
            /// [UserManagementLoadServerFailureState]
            ///
            return const SliverToBoxAdapter(
                child: Center(child: CupertinoActivityIndicator()));
          } else if (state is UserManagementLoadSuccessState) {
            List<UserEntity> user = state.user.users;
            _usersListEntity = state.user;

            return _usersListBuilder(size, user);
          } else if (state is UserManagementSearchResultSuccessState) {
            return _usersListBuilder(size, state.user.users);
          } else if (state is UserManagementSearchFailureState) {
            return const SliverToBoxAdapter(
                child: ErrorMessageBox(
                    message: 'User Not Found!',
                    image:
                        "https://cdn2.iconfinder.com/data/icons/business-1381/1000/accounts___account_user_profile_person_people_not_found_search_find_lost_blocked-512.png"));
          }
          return const SliverToBoxAdapter(
              child: Center(child: CupertinoActivityIndicator()));
        },
      ),
    );
  }

  SliverList _usersListBuilder(Size size, List<UserEntity> user) {
    return SliverList(
      delegate: SliverChildBuilderDelegate(
        (BuildContext context, int index) {
          return Padding(
            padding: EdgeInsets.only(
                top: 10,
                bottom: 10,
                left: size.width * 0.05,
                right: size.width * 0.05),
            child: Wrap(
                alignment: WrapAlignment.spaceBetween,
                direction: Axis.horizontal,
                crossAxisAlignment: WrapCrossAlignment.center,
                children: [
                  _listBody(user[index].name),
                  Container(
                    width: 100,
                    height: 40,
                    padding: const EdgeInsets.all(10),
                    decoration: BoxDecoration(
                        color: primarycolor.withOpacity(0.1),
                        borderRadius: BorderRadius.circular(200)),
                    child: Center(
                      child: Text(
                        user[index].role.first,
                        style: const TextStyle(
                            fontWeight: FontWeight.bold,
                            fontSize: 13,
                            color: Colors.grey),
                      ),
                    ),
                  ),
                  _listBody("Rs. ${user[index].salary.toString()}"),
                  IconButton(
                      onPressed: () {
                        showDialog(
                            context: context,
                            builder: (context) => Container(
                                  color: Colors.transparent,
                                  margin: EdgeInsets.all(size.width * 0.08),
                                  child: UserDetailDialog(
                                    user: user[index],
                                  ),
                                ));
                      },
                      icon: const Icon(
                        Icons.more_horiz_outlined,
                        color: primarycolor,
                      ))
                ]),
          );
        },
        childCount: user.length,
      ),
    );
  }

  Text _listTitle(String text) {
    return Text(
      text,
      style: menuFont,
    );
  }

  Text _listBody(String text) {
    return Text(
      text,
      style: listItemFont,
    );
  }
}

上面代码的cubit

import 'package:bloc/bloc.dart';
import 'package:dartz/dartz.dart';
import 'package:equatable/equatable.dart';

import '../../../../core/error/failures.dart';
import '../../domain/entity/user.list.entity.dart';
import '../../domain/user.mgmt.usecase.dart';

part 'user.management.state.dart';

class UserManagementCubit extends Cubit<UserManagementState> {
  final UserManagementUseCase userManagementUseCase;

  UserManagementCubit({required this.userManagementUseCase})
      : super(UserManagementInitial());

  /// Trigger this event to fetch users list from server
  Future<void> fetchUsersList() async {
    Either<Failure, UsersListEntity> response =
        await userManagementUseCase.getUsersList();

    response.fold((failure) async {
      if (failure == NetworkFailure()) {
        emit(UserManagementLoadNetworkFailureState());
      } else if (failure == ServerFailure()) {
        emit(UserManagementLoadServerFailureState());
      }
    }, (UsersListEntity success) async {
      emit(UserManagementLoadSuccessState(user: success));
    });
  }

  /// Trigger this event to search user from list of users
  Future<void> searchUser(
      {required String username, required UsersListEntity users}) async {
    List<UserEntity> result = [];
    UsersListEntity? list;
    if (username.isEmpty) {
      emit(UserManagementLoadSuccessState(user: users));
    } else if (username.isNotEmpty) {
      for (UserEntity user in users.users) {
        if (user.name.toUpperCase().contains(username.toUpperCase())) {
          result.add(user);
          list = UsersListEntity(users: result);
        }
        if (result.isNotEmpty && username.isNotEmpty) {
          emit(UserManagementSearchResultSuccessState(user: list!));
        } else if (result.isEmpty && username.isNotEmpty) {
          emit(UserManagementSearchFailureState());
        }
      }
    } else {
      emit(UserManagementLoadSuccessState(user: users));
    }
  }
}

错误

E/flutter ( 3949): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Bad state: Cannot emit new states after calling close
E/flutter ( 3949): #0      BlocBase.emit (package:bloc/src/bloc.dart:608:9)
E/flutter ( 3949): #1      UserManagementCubit.fetchUsersList.<anonymous closure> (package:kkkinventory/features/user.management/presentation/cubit/user.management.cubit.dart:29:7)  
E/flutter ( 3949): #2      UserManagementCubit.fetchUsersList.<anonymous closure> (package:kkkinventory/features/user.management/presentation/cubit/user.management.cubit.dart:28:8)  
E/flutter ( 3949): #3      Right.fold (package:dartz/src/either.dart:200:64)
E/flutter ( 3949): #4      UserManagementCubit.fetchUsersList (package:kkkinventory/features/user.management/presentation/cubit/user.management.cubit.dart:22:14)
E/flutter ( 3949): <asynchronous suspension>
E/flutter ( 3949): #5      _UserManagementPageState._call (package:kkkinventory/features/user.management/presentation/pages/user.management.page.dart:32:5)
E/flutter ( 3949): <asynchronous suspension>
E/flutter ( 3949):