首次登录后红色 null 错误只是一秒钟

Question

When i run the app and log-in / or already logged in before closed app => "Null check operator used on a null value" error pops up and it goes away just in a second. I guess user going to page before data came up. If i sign-out and log in with another acc. Red screen wont came up but the last users data appears just for a second then current users data comes after. Could you please help me about this.

My primitiv Sign-in method

Future signIn() async {
try {
  await FirebaseAuth.instance.signInWithEmailAndPassword(
      email: emailController.text.trim(),
      password: passwordController.text.trim(),
  );
  print('Signed In');
} on FirebaseAuthException catch (e) {
  print (e);
  Utils.showSnackBar(e.message);
}}}

User Provider

class UserProvider with ChangeNotifier {
  User? _user;
  final AuthMethods _authMethods = AuthMethods();
  User get getUser => _user!;
  Future<void> refreshUser() async {
    User user = await _authMethods.getUserDetails();
    _user = user;
    notifyListeners();}}

The code i use refresh User welcomepage level

class _welcomePageState extends State<welcomePage> {

  void initState() {
    super.initState();
    addData();
  }
  addData() async{
    UserProvider _userProvider = Provider.of(context,listen: false);
    await _userProvider.refreshUser();
  }

  @override

if that codes not enough to solve i can share all could you please help me to solve this problem.

Answer 1

You are force-unwrapping here: User get getUser => _user;, which means when you hot-reload the app it is null and the crash appears until it is null. you should make it optional and provide a default value so it doesn't crash.