On the code below, profileBloc is initialized in EditProfileScreenState's didChangeDependencies() method.

Should we be calling dispose method on EditProfileScreenState class to dispose the profileBloc ?

If so , how should the profileBloc method be disposed as ProfileBloc class extends Bloc class which doesn't have dispose method?

class Profile extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (BuildContext context) => ProfileBloc(AuthRepo()),
      child: ProfileScreen(),
    );
  }
}

class ProfileScreen extends StatefulWidget {

  @override
  EditProfileScreenState createState() => EditProfileScreenState();
}

class EditProfileScreenState extends State<ProfileScreen> {

  ProfileBloc profileBloc;

  @override
  void didChangeDependencies() {
    profileBloc = BlocProvider.of<ProfileBloc>(context);
    super.didChangeDependencies();
  }

  @override
  void dispose() {
    // TODO: implement dispose
    //profileBloc.dispose() cannot call as ProfileBloc class doesn't have dispose method
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: BlocConsumer<ProfileBloc, ProfileState>(
        listener: (context, state) {
        },
        builder: (BuildContext context,ProfileState state) {
          return RaisedButton(onPressed: ()=>profileBloc.add(SaveProfile("name","email")));
        }
      ));
  }
}

class ProfileBloc extends Bloc<ProfileEvent, ProfileState> {

  AuthRepo authRepo;

  ProfileBloc(this.authRepo) : super(ProfileSaved());

  @override
  Stream<ProfileState> mapEventToState(ProfileEvent event) async* {
    if (event is SaveProfile) {
      //Actions
    }
  }
}


Solution 1: anandasubedi

While I was searching, I found the solution.

We don't need to initialize the profileBloc in didChangeDependencies().

We can access the add method directly from the BlocProvider using:

BlocProvider.of<ProfileBloc>(context).add(ProfileSaved())

We can remove following section from EditProfileScreenState class.

ProfileBloc profileBloc;

  @override
  void didChangeDependencies() {
    profileBloc = BlocProvider.of<ProfileBloc>(context);
    super.didChangeDependencies();
  }

Moreover, In ProfileBloc class we can use close method in case we need to cancel any streams.

@override
  Future<void> close() {
    //cancel streams
    super.close();
  }