Add BLoC

Bloc will have modules for every API to fetch data and provide it to the UI. The module folder will have 4 files: events, states, bloc and public(which will export all the files).

 /shared
    /lib
      /modules
        /authentication
          /bloc
            /authentication-bloc
              /authentication_bloc.dart
              /authentication_state.dart
              /authentication_event.dart
              /authentication_bloc_public.dart
          /bloc_controller.dart

Insert the following in the authentication_state.dart file:

import 'package:meta/meta.dart';
import 'package:equatable/equatable.dart';
import 'package:shared/modules/authentication/models/current_user_data.dart';

abstract class AuthenticationState extends Equatable {
  const AuthenticationState();

  @override
  List<Object> get props => [];
}

class AppAutheticated extends AuthenticationState {}

class AuthenticationInitial extends AuthenticationState {}

class AuthenticationLoading extends AuthenticationState {}

class AuthenticationStart extends AuthenticationState {}

class UserLogoutState extends AuthenticationState {}

class SetUserData extends AuthenticationState {
  final CurrentUserData currentUserData;
  SetUserData({this.currentUserData});
  @override
  List<Object> get props => [currentUserData];
}

class AuthenticationNotAuthenticated extends AuthenticationState {}

class AuthenticationFailure extends AuthenticationState {
  final String message;

  AuthenticationFailure({@required this.message});

  @override
  List<Object> get props => [message];
}

Add the code shown below to the authentication_event.dart file:

import 'package:meta/meta.dart';
import 'package:equatable/equatable.dart';

abstract class AuthenticationEvent extends Equatable {
  const AuthenticationEvent();

  @override
  List<Object> get props => [];
}

// Fired just after the app is launched
class AppLoadedup extends AuthenticationEvent {}

class UserLogOut extends AuthenticationEvent {}

class GetUserData extends AuthenticationEvent {}

class UserSignUp extends AuthenticationEvent {
  final String email;
  final String password;
  UserSignUp({@required this.email, this.password});

  @override
  List<Object> get props => [email, password];
}

class UserLogin extends AuthenticationEvent {
  final String email;
  final String password;
  UserLogin({@required this.email, this.password});

  @override
  List<Object> get props => [email, password];
}

Insert the following in the authentication_bloc.dart file:

class AuthenticationBloc
    extends Bloc<AuthenticationEvent, AuthenticationState> {
  AuthenticationBloc() : super(AuthenticationInitial());
  final AuthenticationRepository authenticationService =
      AuthenticationRepository();
  @override
  Stream<AuthenticationState> mapEventToState(
      AuthenticationEvent event) async* {
    final SharedPreferences sharedPreferences = await prefs;
    if (event is AppLoadedup) {
      yield* _mapAppSignUpLoadedState(event);
    }

    if (event is UserSignUp) {
      yield* _mapUserSignupToState(event);
    }

    if (event is UserLogin) {
      yield* _mapUserLoginState(event);
    }
    if (event is UserLogOut) {
      sharedPreferences.setString('authtoken', null);
      sharedPreferences.setInt('userId', null);
      yield UserLogoutState();
    }
    if (event is GetUserData) {
      int currentUserId = sharedPreferences.getInt('userId');
      final data = await authenticationService.getUserData(currentUserId ?? 4);
      final currentUserData = CurrentUserData.fromJson(data);
      yield SetUserData(currentUserData: currentUserData);
    }
  }

Insert the code shown below in the authentication_bloc_public.dart file:

export 'package:shared/modules/authentication/bloc/authentication/authentication_bloc.dart';
export 'package:shared/modules/authentication/bloc/authentication/authentication_event.dart';
export 'package:shared/modules/authentication/bloc/authentication/authentication_state.dart';

Add the code shown below to the bloc_controller.dart file:

import 'package:shared/main.dart';

class BlocController {
  BlocController._();
  static BlocController _instance = BlocController._();
  factory BlocController() => _instance;

  AuthenticationBloc authenticationBloc = AuthenticationBloc();
}

To use it in the UI, you can access the instance as shown below:

AuthenticationBloc authenticationBloc = BlocController().authenticationBloc;