Setting and retrieving user profile flutter

Question

New to dart/flutter. I've been following some tutorials on how to properly set up a user profile and be able to make it available in memory instead of having to fetch details from firebase and to get it in one place. But I have hit some late initialization errors when trying to retrieve the data.

here's my user model:


    class LakoUser  {
    
      //todo fill this with the necessary fields to create just 1 place to

      // retrieve the user's data that is global.... bad idea?
      // I tried extending this with User Class but got confused. I was wishing I can get some 
      // other fields of the User class for later use.

      final  String  uid;
  
      final String? username;
      final String? buyerMarker;
      final String? email;
      final String? mobileNum;
    
      LakoUser(
          {
            required this.uid,
            this.username,
            this.buyerMarker,
            this.email,
            this.mobileNum,
          });
    
      
       LakoUser.fromData(Map data)
        : uid = data['buyerId'],
          username = data['username'],
          buyerMarker = data['buyerMarker'],
          email = data['email'],
          mobileNum = data['mobileNum'];

    // storing to json format for quick saving to db
    Map toJson() {
      return {
        'buyerId': uid,
        'username': username,
        'buyerMarker': buyerMarker,
        'email': email,
        'mobileNum': mobileNum,

      };}

    factory LakoUser.fromJson(Map  json)  {
       return LakoUser(
                 uid: json['buyerId'],
                 username: json['username'],
                 buyerMarker : json['buyerMarker'],
                 email: json['email'],
                 mobileNum: json['mobileNum']
       );}}

AuthService:

class AuthService {

  final FirebaseAuth _auth = FirebaseAuth.instance;
  DatabaseService db = DatabaseService();

  late LakoUser _currentUser;
  LakoUser get currentUser  => _currentUser;

  

  //returns a AuthResult object that can ba a User or null once created/called thru registrations or signins
  LakoUser? _userfromSignIn(User? user) {

    return user != null ? LakoUser(uid: user.uid) : null;
  }

  //Fill _currentUser with data from the logged in user taken from db earlier
   populateCurrentUser(String? user) async {

    if (user != null) {
      //currentUser is a map object
      _currentUser = await db.getUser(user);
      print(_currentUser.mobileNum);
    }
  }

 
  Stream get user {

    // A sign-in or out is monitored and sent to 'user' parameter of _userfromSignIn
    return _auth.authStateChanges()
        .map((User? user) => _userfromSignIn(user));

  }
Future signInWithEmailAndPassword(String email, String password) async {

try {
  UserCredential resultOfSignIn = await _auth.signInWithEmailAndPassword(email: email, password: password);
  User? user = resultOfSignIn.user;

  await populateCurrentUser(user?.uid); //populate  this works. can confirm it fetches data
  return _userfromSignIn(user);

}catch(e) {
  print(e.toString());
  // return e;
  return null;
}

}

My Database Service:

Future  getUser(String uid) async {

//todo: fetch data from buyersCollection and save it a json
try {
  var document = await buyersCollection.doc(uid).get();
   Map  userData = document.data() as Map ;
  

  // var userData = await buyersCollection.doc(uid).get();

  return LakoUser.fromJson(userData);

} catch (e) {
  return e;
}

}

Im trying to setup a profile setting page:

  class ProfileSettings extends StatefulWidget {
  const ProfileSettings({Key? key}) : super(key: key);

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

class _ProfileSettingsState extends State {

  String? username = "";
  String? email = "";
  final usernameCont = TextEditingController(text: "");
  final emailCont = TextEditingController(text: "");
  DatabaseService db = DatabaseService();


  final _profileSettingsKey = GlobalKey ();

  bool disableFocus = true;
  String? avatar = "";

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

   ....  the Widget tree ...

Future  prefillFields() async {
    //tried calling global auth and making an instance of AuthService here same error.    
    await auth.populateCurrentUser(auth.currentUser.uid);   <--- error begins here

    //how to retrieve the values so ican place them on the widgets below?
    // ignore the code below as i was trying to refactor it to get data from LakoUser instead of db

    username = db.username;

    usernameCont.value = (TextEditingValue(text: username.toString()));

    email = db.email;
    emailCont.value = (TextEditingValue(text: email.toString()));

    setState(() {

    });
    return null;
  }

It seems that even right after signin I lose the data in currentUser:

    Unhandled Exception: LateInitializationError: Field '_currentUser@163456873' has not been initialized. E/flutter (31679): #0 AuthService._currentUser ...
E/flutter ( 6069): #0      AuthService.currentUser (package:mlako/services/auth.dart)

How to properly store it after registration/signin or just after startup when the app already remembers the last logged in user? Have so many questions. Thanks in advance!

Setting and retrieving user profile flutter

Answers (1)

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