How to use Flutter Bloc with Firebase Phone Auth

Issue

I’m trying to implement Firebase phone authorization using Flutter Bloc pattern.
I have the following code

import 'dart:async';
import 'package:bloc/bloc.dart';
import 'package:firebase_auth/firebase_auth.dart';
import './bloc.dart';

class AuthBloc extends Bloc<AuthEvent, AuthState> {
  final FirebaseAuth _auth = FirebaseAuth.instance;

  @override
  AuthState get initialState => AuthNotStarted();

  @override
  Stream<AuthState> mapEventToState(
    AuthEvent event,
  ) async* {
    if (event is VerifyPhone) {
      yield* _mapVerifyPhoneToState(event);
    }
  }

  Stream<AuthState> _mapVerifyPhoneToState(VerifyPhone event) async* {
    yield AuthStarted();
    _auth.verifyPhoneNumber(
        phoneNumber: "+" + event.phoneNumber,
        timeout: Duration(seconds: 60),
        verificationCompleted: (AuthCredential authCredential) {
          print("verification completed: auth credential");
        },
        verificationFailed: (AuthException authException) {
          print("verification failed: auth exception");
          print(authException.message);
        },
        codeSent: (String verificationId, [int forceResendingToken]) {
          print("code sent verification id" + verificationId);
        },
        codeAutoRetrievalTimeout: (String verificationId) {
          print("auto time" + verificationId);
        });
  }
}

But i can’t use yield inside verifyPhoneNumber callbacks.
The question is how to yield different states inside of callback functions?

Solution

You can add an event from your callback. For example, in verificationCompleted, you can do:

verificationCompleted: (AuthCredential authCredential) {
    print("verification completed: auth credential");
    add(AuthCompleted());
},

And you can handle the AuthCompleted() event on mapEventToState:

@override
  Stream<AuthState> mapEventToState(
    AuthEvent event,
  ) async* {
    if (event is VerifyPhone) {
      yield* _mapVerifyPhoneToState(event);
    }
    if (event is AuthCompleted){
      //Here you can use yield and whathever you want
    }
  }

Answered By – Ademir Villena Zevallos

Answer Checked By – Jay B. (FlutterFixes Admin)