Question

我正在使用BLoC模式学习和构建Flutter应用程序，并且在许多教程和存储库中，我看到人们对于BLoC的每个状态都具有单独的类，而对于其他具有相同属性的州类则具有单独的类定义。是否有用于定义状态类的标准BLoC方法？还是个人选择？

具有多个状态类的示例

abstract class LoginState extends Equatable {
  LoginState([List props = const []]) : super(props);
}

class LoginInitial extends LoginState {
  @override
  String toString() => 'LoginInitial';
}

class LoginLoading extends LoginState {
  @override
  String toString() => 'LoginLoading';
}

class LoginFailure extends LoginState {
  final String error;

  LoginFailure({@required this.error}) : super([error]);

  @override
  String toString() => 'LoginFailure { error: $error }';
}

具有单个状态类的示例

@immutable
class MyFormState extends Equatable {
  final String email;
  final bool isEmailValid;
  final String password;
  final bool isPasswordValid;
  final bool formSubmittedSuccessfully;

  bool get isFormValid => isEmailValid && isPasswordValid;

  MyFormState({
    @required this.email,
    @required this.isEmailValid,
    @required this.password,
    @required this.isPasswordValid,
    @required this.formSubmittedSuccessfully,
  }) : super([
          email,
          isEmailValid,
          password,
          isPasswordValid,
          formSubmittedSuccessfully,
        ]);

  factory MyFormState.initial() {
    return MyFormState(
      email: '',
      isEmailValid: false,
      password: '',
      isPasswordValid: false,
      formSubmittedSuccessfully: false,
    );
  }

  MyFormState copyWith({
    String email,
    bool isEmailValid,
    String password,
    bool isPasswordValid,
    bool formSubmittedSuccessfully,
  }) {
    return MyFormState(
      email: email ?? this.email,
      isEmailValid: isEmailValid ?? this.isEmailValid,
      password: password ?? this.password,
      isPasswordValid: isPasswordValid ?? this.isPasswordValid,
      formSubmittedSuccessfully:
          formSubmittedSuccessfully ?? this.formSubmittedSuccessfully,
    );
  }

  @override
  String toString() {
    return '''MyFormState {
      email: $email,
      isEmailValid: $isEmailValid,
      password: $password,
      isPasswordValid: $isPasswordValid,
      formSubmittedSuccessfully: $formSubmittedSuccessfully
    }''';
  }
}

何时应使用哪个？两者之间的优缺点是什么？

BLoC-每个州都应该是一个单独的类吗？

0 个答案: