Flutter cubit blocprovider couldn't find the correct provider

Question

I am building a flutter app, in which the user can sign in with a google account. I'd like to manage this with cubit. I use Blocprovider to provide the cubit in the widget tree. The blocprovider is inside a futurebuilder in the runApp function. Here's my code:

The main.dart:

home: FutureBuilder(
          future: initRepo.initialize(),
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              return BlocProvider(
                  create: (context) => SignInCubit(googleAuthRepo),
                  child: SignInPage(googleAuthRepo, initRepo, databaseRepo));
            }
            return SplashScreen();
          },
        ));

The SignInPage widget:

class SignInPage extends StatelessWidget {
  final GoogleAuthRepo _googleAuthRepo;
  final InitRepo initRepo;
  final DatabaseRepo _databaseRepo;

  SignInPage(this._googleAuthRepo, this.initRepo, this._databaseRepo);

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: BoxDecoration(
          gradient: LinearGradient(
              begin: Alignment.topCenter,
              end: Alignment.bottomCenter,
              colors: [Colors.grey[900], Colors.grey[800]])),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          Image(image: AssetImage("lib/assets/icon.png")),
          BlocBuilder(
            builder: (context, state){
              if(state is SignInInitial){
                return buildInitial();
              }
              else if(state is SignInLoading){
                return buildLoading();
              }
              else if(state is SignInLoaded){
                return buildLoaded();
              }
              return buildInvalidUser();
            },
          )
        ],
      ),
    );
  }

  Widget buildInitial() {
    return GoogleButton(
        this._databaseRepo, this.initRepo, this._googleAuthRepo);
  }

  Widget buildLoading() {
    return CircularProgressIndicator(
      valueColor: new AlwaysStoppedAnimation<Color>(
        Colors.blueGrey,
      ),
    );
  }

  Widget buildInvalidUser() {
    return Column(
      children: [
        GoogleButton(this._databaseRepo, this.initRepo, this._googleAuthRepo),
        Text(
          "Bejelentkezési hiba. Használj e5vos.hu-s e-mail címet!", //This is an error message, if the user doesn't use a specific email domain
          style: TextStyle(color: Colors.red),
        )
      ],
    );
  }

  Widget buildLoaded(){
    return MainPage(_databaseRepo, initRepo);
  }
}

The GoogleButton widget:

class GoogleButton extends StatefulWidget {
  @override
  _GoogleButtonState createState() => _GoogleButtonState();

  final DatabaseRepo databaseRepo;
  final InitRepo initRepo;
  final GoogleAuthRepo _googleAuthRepo;

  GoogleButton(this.databaseRepo, this.initRepo, this._googleAuthRepo);
}

class _GoogleButtonState extends State<GoogleButton> {

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Container(
        height: MediaQuery.of(context).size.height / 15,
        width: MediaQuery.of(context).size.width / 7,
        child: ButtonTheme(
          minWidth: 300,
          child: OutlineButton(
              borderSide: BorderSide(color: Colors.blueGrey, width: 1),
              shape:
                  RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
              onPressed: () async {
                final signInCubit = BlocProvider.of<SignInCubit>(context);
                signInCubit.signInWithGoogle();
              },
              child: Padding(
                padding: const EdgeInsets.fromLTRB(0, 10, 0, 10),
                child: Center(
                        child:
                          Text(
                              'Bejelentkezés',
                              style: TextStyle(
                                fontSize: 20,
                                color: Colors.blueGrey,
                              ),
                            ),
                      ),
              )),
        ),
      ),
    );
  }
}

When I run it, it throws the following error:

I tried to do what it recommends and swap the BlocProvider with Provider, so my code would look like this:

home: FutureBuilder(
          future: initRepo.initialize(),
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              return Provider<SignInCubit>(
                create: (context) => SignInCubit(googleAuthRepo),
                builder: (context) {
                  return SignInPage(googleAuthRepo, initRepo, databaseRepo)
                  ,
                },);
            }
            return SplashScreen();
          },
        ));

But then i get the argument type 'SignInPage Function(BuildContext)' can't be assigned to the parameter type 'Widget Function(BuildContext, Widget)' error.

Answer 1

I guess one needs to see your SignInPage code. Currently it seems your are missing the BlocBuilder as a child of BlocProvider.

In general your structure looks a bit - "mixed". Why do you use a BlocProvider as a child of a FutureBuilder? I would initialize the bloc which in turn initializes all necessary data and once ready yields the state to render the screen (and an activity indicator until then)