无法在此 BlocBuilder<WelcomeBloc， WelcomeState> 小部件上方找到正确的 Provider<WelcomeBloc>

问：

我解决了错误类型不匹配的问题，但现在抛出了另一个异常

不能将参数类型“List<dynamic>”分配给参数类型“List<SingleChildWidget>”

这是控制台输出

════════ 小部件库捕获的异常═══════════════════════════════════ 引发了以下 ProviderNotFoundException 生成 Welcome（state： _WelcomeState#276b6）： 错误：无法在此 BlocBuilder<WelcomeBloc、WelcomeState> 小部件上方找到正确的提供程序

发生这种情况的原因是您使用了不包含提供程序的 由您选择。有几种常见方案：BuildContext

• 您在 中添加了新的提供程序并执行了热重载。 要解决此问题，请执行热重启。main.dart

• 您尝试读取的提供程序位于不同的路由中。

  提供程序是有“范围”的。因此，如果您在路由中插入 of provider，那么 其他路由将无法访问该提供程序。

• 您使用了您尝试读取的提供程序的祖先。BuildContext

  确保 BlocBuilder<WelcomeBloc， WelcomeState> 位于 MultiProvider/Provider 下。 这通常发生在创建提供程序并尝试立即读取它时。

  例如，代替：

  Widget build(BuildContext context) {
    return Provider<Example>(
      create: (_) => Example(),
      // Will throw a ProviderNotFoundError, because `context` is associated
      // to the widget that is the parent of `Provider<Example>`
      child: Text(context.watch<Example>().toString()),
    );
  }
  

  考虑像这样使用：builder

  Widget build(BuildContext context) {
    return Provider<Example>(
      create: (_) => Example(),
      // we use `builder` to obtain a new `BuildContext` that has access to the provider
      builder: (context, child) {
        // No longer throws
        return Text(context.watch<Example>().toString());
      }
    );
  }
  

导致错误的相关小部件是

欢迎页面.dart：19

当异常被抛出时，这是堆栈。

这是我修改后的main.dart文件

  Widget build(BuildContext context) {
    return MultiBlocProvider(
      providers: AppPages.allBlocProviders(context) ,
      child: ScreenUtilInit(
      builder: (context, child) {
          return MaterialApp(
            debugShowCheckedModeBanner: false,
            theme: ThemeData(
              appBarTheme: const AppBarTheme(
                iconTheme: IconThemeData(
                  color: AppColors.primaryText
                ),
                elevation: 0,
                backgroundColor: Colors.white
              )
            ),
            onGenerateRoute: AppPages.GenerateRouteSettings,
          );
        },
      )
    );
  }

这是我的welcome.dart文件。

    return  BlocBuilder<WelcomeBloc, WelcomeState>(
      builder: (context, state) {
        return Container(
          color: Colors.white,
          child: Scaffold(
            body: Container(
              margin: EdgeInsets.only(top: 34.h),
              width: 375.w,
              child: Stack(
                alignment: Alignment.topCenter,
                children: [
                  PageView(
                    controller: pageController,
                    onPageChanged: (value) {
                      state.page = value;
                      BlocProvider.of<WelcomeBloc>(context).add(WelcomeEvent());
                      // print(value);
                    },
                    children: [
                      _page(
                        1,
                        context,
                        "Next",
                        "First See Learning",
                        "Forget about a for of paper all knowledge in on learning",
                        "assets/images/reading.png"
                      ),
                      _page(
                        2,
                        context,
                        "Next",
                        "Connect With Everyone",
                        "Always keep in touch with your tutor & friend, Let's get connected",
                        "assets/images/boy.png"
                      ),
                      _page(
                        3,
                        context,
                        "Get Started",
                        "Always Fascinated Learning",
                        "Anywhere, anytime, The time is at our direction so study whenever you want",
                        "assets/images/man.png"
                      ),
                    ],
                  ),
                  Positioned(
                    bottom: 100.h,
                    child: DotsIndicator(
                      position: state.page,
                      dotsCount: 3,
                      mainAxisAlignment: MainAxisAlignment.center,
                      decorator: DotsDecorator(
                        color: AppColors.primaryThirdElementText,
                        activeColor: AppColors.primaryElement,
                        size: const Size.square(8.0),
                        activeSize: const Size(18.0, 8.0),
                        activeShape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(5.0)
                        )
                      ),
                    )
                  )
                ],
              ),
            ),
          ),
        );
      },
    );
  }

这是我修改后的pages.dart文件

  static List<PageEntity> routes (){
    return [
      PageEntity(
      route: AppRoutes.INITIAL, 
      page: const Welcome(), 
      bloc: BlocProvider(create: (context)=>WelcomeBloc(),)
    ),
      PageEntity(
      route: AppRoutes.SING_IN, 
      page: const SignInPage(), 
      bloc: BlocProvider(create: (context)=>SignInBlocs(),)
    ),
      PageEntity(
      route: AppRoutes.REGISTER, 
      page: const Register(), 
      bloc: BlocProvider(create: (context)=>RegisterBlocs(),)
    ),
    ];
  }


// return all the bloc providers
   static List<BlocProvider> allBlocProviders(BuildContext context){
    List<BlocProvider> blocProviders = <BlocProvider>[];
    for(var blocs in routes()){
      if(blocs.bloc != null){
        blocProviders.add(blocs.bloc!);
      }
    }
    return blocProviders;
  }


  // model that cover entire screen as we click on navigator object
  static MaterialPageRoute GenerateRouteSettings(RouteSettings settings){
    if(settings.name !=null){
      // check for route name matching when navigator gets triggered.
      var result = routes().where((element) => element.route == settings.name);
      if(result.isNotEmpty){
        return MaterialPageRoute(builder: (_)=> result.first.page, settings: settings);
      }
    }
    return MaterialPageRoute(builder: (_)=> const SignInPage(), settings: settings);
  }
}


class PageEntity{
  String route;
  Widget page;
  BlocProvider? bloc;

  PageEntity({required this.route, required this.page,  this.bloc});
}

如何处理此错误。我累了，但找不到解决方案。