Firebase 和 React Native：onAuthStateChanged 没有被触发

Question

So I'm developing my very first React native app with Firebase and I have the following structure in my code:

ComponentDidMount(){
    this.verifySession();
    console.log("Component did mount");
}

verifySession = () =>{
    console.log("inside VS");
    firebase.auth().onAuthStateChanged(user =>{
        if(user){
            this.props.navigation.navigate('Dashboard');
            console.log("dashboard");
        }else{
            this.props.navigation.navigate('Login');
            console.log("Login");
        }
    });
}

Problem is, my verifySession function is not getting triggered. Actually, I'm not getting any logs so I think ComponentDidMount is not being executed either. This code is placed within my LoadingScreen component.

Here's my app.js where I initialize the Firebase conf:

import * as firebase from 'firebase';
import {firebaseConfig} from './data/config';


const Stack = createStackNavigator();
firebase.initializeApp(firebaseConfig);

I've also tried the following for my LoadingScreen:

import Dashboard from './dashboard';
import Login from './login';

render(){
    firebase.auth().onAuthStateChanged(function(user){
        if(user){
            return (<Dashboard/>);
        }else{
            return (<Login/>);
        }  
    });

    return(
        <View>
            <Text>Verifying session...</Text>
        </View>
    )
}

Login should get rendered but instead it shows "Verifying session" which makes me think if the statement is not getting executed at all.

Any thoughts/recommendations on this matter will be appreciated.

Answer 1

onAuthStateChanged is meant to add an observer and not to be called directly. Could be it's not firing because the user's login-status is not changing at all and you're not attempting to sign-in anyone in, so there's nothing to trigger it. Try implementing auth().createUserWithEmailAndPassword(email, password) or `auth().signInWithEmailAndPassword(email, password)' and test out user creation/sign-in.

This article may also be of use; it puts an auth observer in a separate component and allows you to navigate between two navigation stacks based on user's login status: https://heartbeat.fritz.ai/how-to-manage-authentication-flows-in-react-native-with-react-navigation-v5-and-firebase-860f57ae20d3