引发了另一个异常：错误：在此 BlocSelector<HCubit, HState, HState> Widget 上方找不到正确的 Provider<HState>

Posted 2023-02-23

【中文标题】引发了另一个异常：错误：在此 BlocSelector<HCubit, HState, HState> Widget 上方找不到正确的 Provider<HState>

【英文标题】：Another exception was thrown: Error: Could not find the correct Provider<HState> above this BlocSelector<HCubit, HState, HState> Widget

【发布时间】：2021-11-16 22:09:08

【问题描述】：

我在freezd 中使用cubit。我在底部表格中有一个输入文本表单字段，一切都很完美，但是一旦我单击输入表单字段并输入任何字母，就会发生此异常。

抛出了另一个异常：错误：在此 BlocSelector Widget 上方找不到正确的 Provider

文本表单域代码为：

class TextInput extends StatelessWidget 
  @override
  Widget build(BuildContext context) 
    TextEditingController _textEditingController = TextEditingController();
    return BlocSelector<HCubit, HState, String?>(
        selector: (state) 
          return state.maybeMap(
              orElse: () ,
              inputTextValue: (val) =>
                  val.inputTextValue.input.fold((l) => l.msg, (r) => null));
        ,
        builder: (context, state) 
          return TextFormField(
              textAlign: TextAlign.start,
              onChanged: (String value) => context
                  .read<HState>()
                  .maybeMap(inputTextValue: (value) => value, orElse: () ),
              validator: (String? validator) => context
                  .read<HState>()
                  .maybeWhen(
                      orElse: () ,
                      inputTextValue: (val) =>
                          val.input.fold((l) => l.msg, (r) => null)),
              );
        ,
      ),
    );
  

素材应用代码：

class AppWidget extends StatelessWidget 
  @override
  Widget build(BuildContext context) 
    return Sizer(
      builder: (context, orientation, deviceType) 
        return MaterialApp(
          BlocProvider<HCubit>(
            lazy: false,
            create: (context) => HCubit(),
            child: const
             HomePage(),
          ),
        );
      ,
    );
  

区号为：

class HCubit extends Cubit<HState> 
  HCubit() : super(const HState.initial());
  void addNewNoteButton(required bool isClicked) =>
      emit(HState.isClicked(isClicked: isClicked));

  void textInputNote(required String textNote) =>
      emit(HState.inputTextValue(inputTextValue: Note(textInput: textNote)));

状态码是：

abstract class HState with _$HState 
  const factory HState.initial() = _Initial;
  const factory HState.inputTextValue(required Note inputTextValue)=InputTextValue;
  const factory HState.isClicked(required bool isClicked)=IsClicked;

【参考方案1】：

在您的材料应用程序代码中有语法错误应该是这样的：

class AppWidget extends StatelessWidget 
  @override
  Widget build(BuildContext context) 
    return Sizer(
      builder: (context, orientation, deviceType) 
        return MaterialApp(
          home: BlocProvider<HCubit>(
            lazy: false,
            create: (context) => HCubit(),
            child: const
             HomePage(),
          ),
        );
      ,
    );