CODEWITHSUNDEEP
flutterblocflutter-bloc
Zhu
Zhu

Reputation: 407

BlocProvider.of() called with a context that does not contain a Bloc of type Bloc<dynamic,dynamic>

Error: I/flutter ( 5919): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════ I/flutter ( 5919): The following assertion was thrown building Builder: I/flutter ( 5919): BlocProvider.of() called with a context that does not contain a Bloc of type Bloc. I/flutter ( 5919): No ancestor could be found starting from the context that was passed to I/flutter ( 5919): BlocProvider.of>(). I/flutter ( 5919):
This can happen if the context you used comes from a widget above the BlocProvider. I/flutter ( 5919): The context used was: BlocBuilder, dynamic>(dirty, state: I/flutter ( 5919): _BlocBuilderBaseState, dynamic>#55a7d(lifecycle state: created)) I/flutter ( 5919): The relevant error-causing widget was: I/flutter ( 5919): MaterialApp /lib/main.dart:35:12

Here's my main

void main() {
  final StorageRepository storageRepository = StorageRepository();
  final AuthenticationRepository authenticationRepository =
      AuthenticationRepository();
  runApp(BlocProvider<AuthenticationBloc>(
      create: (_) => AuthenticationBloc(
          authenticationRepository: authenticationRepository,
          storageRepository: storageRepository),
      child: MyApp()));
}

MaterialApp Widget

MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(primarySwatch: Colors.deepPurple),
      home: BlocBuilder(
        builder: (context, state) {
          print(state);
          if (state is Authenticated) {
            return MainPage();
          } else if (state is Unauthenticated) {
            return LoginPage();
          } else if (state is Uninitialized) {
            return SplashScreen();
          }

          return Container();
        },
      ),

Upvotes: 4

Views: 4282

Answers (2)

Jitesh Mohite
Jitesh Mohite

Reputation: 34270

As the error, itself suggest BlocProvider not accessing the right context to use the bloc

MultiBlocProvider provides the ability to add multiple providers which then can get the right context access as MultiBlocProvider converts the BlocProvider list into a tree of nested BlocProvider widgets.

MultiBlocProvider(
          providers: [
            BlocProvider<YourBloc>(
                create: (BuildContext context) =>)
          ],
          child: MaterialApp(
            home: BlocBuilder<YourBloc, YourState>(

Upvotes: 0

Federick Jonathan
Federick Jonathan

Reputation: 2864

You forget to give the Bloc and State type to the BlocBuilder Widget

MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(primarySwatch: Colors.deepPurple),
      /// You need to specify the type here, 
      /// that's why you got error Bloc<dynamic, dynamic>
      home: BlocBuilder<AuthenticationBloc, AuthenticationState>(
        builder: (context, state) {
          print(state);
          if (state is Authenticated) {
            return MainPage();
          } else if (state is Unauthenticated) {
            return LoginPage();
          } else if (state is Uninitialized) {
            return SplashScreen();
          }

          return Container();
        },
      ),

Upvotes: 5

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