The getter 'email' was called on null

Question

I'm trying to make a chat between two people using Flutter and Firebase but I'm facing an error when I connect into my app using Firebase's signInWithEmailAndPassword, it tells me:

The getter 'email' was called on null. Receiver: null Tried calling: email

And Flutter also tells me the error come from the MaterialApp widget from my main.dart which doesn't help me to find the error..

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:social/responsive/size_config.dart';
import 'settings.dart';
import 'home.dart';

final _firestore = Firestore.instance;
FirebaseUser loggedInUser;


class ActivityFeed extends StatefulWidget {
  static const String id = 'activity_feed_screen';
  @override
  _ActivityFeedState createState() => _ActivityFeedState();
}

class _ActivityFeedState extends State<ActivityFeed> {
  final _auth = FirebaseAuth.instance;

  @override
  void initState() {
    super.initState();
    getCurrentUser();
  }

  void getCurrentUser() async {
    try {
      final user = await _auth.currentUser();
      if (user != null) {
        loggedInUser = user;
      }
    } catch (e) {
      print(e);
    }
  }

  @override
  Widget build(BuildContext context) {

    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Expanded(
            child: Container(
              color: Colors.red,
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
                    UserInfo(),
                    FlatButton(
                      child: Icon(
                        Icons.settings,
                        color: Colors.white,
                      ),
                      onPressed: () {
                        Navigator.pushNamed(context, Settings.id);
                      },
                    ),
                  FlatButton(
                    child: Icon(
                      Icons.not_interested,
                      color: Colors.white,
                    ),
                    onPressed: () {
                      _auth.signOut();
                      Navigator.pushNamed(context, Home.id);
                    },
                  ),
                ],
              ),
            ),
          )
        ],
      ),
    );
  }
}

class UserInfo extends StatefulWidget {
  @override
  _UserInfoState createState() => _UserInfoState();
}

class _UserInfoState extends State<UserInfo> {

  String email = loggedInUser.email;
  String username;

  @override
  void initState() {
    super.initState();
    getUsername();
  }

  void getUsername() async {
    DocumentReference docRef = _firestore.collection('users').document(email);
    docRef.get().then((snapshot) {
      if (snapshot.exists) {
        username = snapshot.data['username'];
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    SizeConfig().init(context);
    return Column(
        children: <Widget>[
          Text(
            'Welcome $username',
            style: TextStyle(
                fontFamily: 'Amatic',
                fontSize: SizeConfig.safeBlockHorizontal * 10),
          ),
        ],
      )
    ;
  }
}

So basically what I am just trying to display 'Welcome' + the username, but it doesn't want, my Firebase Database have one collection named 'users', where the document names are the email the user used when he created his account.

All the Register/Log-In process seems to work fine.

If someone has a clue of what is happening that would be awesome, thanks.

Is your document key is your email, can you show us your firestore sturucture? — Blasanka
@Blasanka Thank you for your answer, i made a screen for you imgur.com/GPQzAIo — Larva Pox

easeccy easeccy · Accepted Answer · 2020-02-04T10:19:25

You initialize username as null. You can either check it on the widget tree

username != null ? Text(
        'Welcome $username',
        style: TextStyle(
            fontFamily: 'Amatic',
            fontSize: SizeConfig.safeBlockHorizontal * 10),
        ) : CircularProgressIndicator()

and set it via setState()

setState(() {
   username = snapshot.data['username'];
});

Another solution is to change

String username;

to

String username = '';

You should use a state management method by the way. setState() is very primitive and you will end up having sphagetti code if you use it as a state management solution.

The getter 'email' was called on null

1 Answers