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Flutter中的StateError

helper mobile dart flutter

ÐÐ°Ð·Ð°Ñ ÐÐ°ÑÑÐ¸Ð½ÐºÐ¾ · 技术社区 · 2 年前

如何修复此错误:在没有注册事件处理程序的情况下调用了StateError(错误状态:add(SignUp Button Pressed))。请确保通过在((event,emit){…})上注册处理程序

SignUpBloc:

import 'package:bloc/bloc.dart';
import 'package:equatable/equatable.dart';
import '../../domain/repositories/user_repository.dart';

part 'sign_up_event.dart';
part 'sign_up_state.dart';

class SignUpBloc extends Bloc<SignUpEvent, SignUpState> {
  final UserRepository userRepository;

  SignUpBloc({required this.userRepository}) : super(SignUpInitial());

  @override
  Stream<SignUpState> mapEventToState(SignUpEvent event) async* {
    if (event is SignUpButtonPressed) {
      yield SignUpLoading();

      try {
        final email = event.email;
        final password = event.password;

        
        final result = await userRepository.registerUser(email, password);
        
        yield result.fold(
          (failure) => SignUpError(message: failure.toString()),
          (user) => SignUpSuccess(email: user.email),
        );
      } catch (error) {
        yield SignUpError(message: error.toString());
      }
    }
  }
}

1 回复 | 直到 2 年前

ryandra 2 年前

根据你的错误,我有另一种使用bloc的方法 handler via on((event, emit) {...})) .

import 'package:bloc/bloc.dart';
import 'package:equatable/equatable.dart';
import '../../domain/repositories/user_repository.dart';

part 'sign_up_event.dart';
part 'sign_up_state.dart';

class SignUpBloc extends Bloc<SignUpEvent, SignUpState> {
  final UserRepository userRepository;

  SignUpBloc({required this.userRepository}) : super(SignUpInitial());

  on<SignUpEvent>((event, emit) async {
    emit(SignUpLoading());

    try {
      final email = event.email;
      final password = event.password;

      
      final result = await userRepository.registerUser(email, password);
      
      await result.fold(
        (failure) async => emit(SignUpError(message: failure.toString())),
        (user) async => emit(SignUpSuccess(email: user.email),
      ));
    } catch (error) {
      emit(SignUpError(message: error.toString()));
    }
  });
}

请理解集团的概念。Bloc有3个文件, event || bloc || state .

事件用于对集团的任何输入。
Bloc是您想对来自的输入数据变量执行的任何操作事件
国家是集团的产物,永远使用 emit() .

dpz.314 2 年前

mapEventToState方法通常用于Flutter Blob库的旧版本中。

对于新版本

class SignUpBloc extends Bloc<SignUpEvent, SignUpState> {
  SignUpBloc({required this.userRepository}) : super(SignUpInitial()){
    on<SignUpButtonPressed>(_handleSignUpButtonPressed);
  };

  final UserRepository userRepository;
  
  Future _handleSignUpButtonPressed(SignUpButtonPressed event, Emitter<SignUpState> emit) async {
    emit(SignUpLoading());
    //...
    //your logic
  }
}