CODEWITHSUNDEEP
flutterdartgoogle-cloud-firestoregoogle-signin
rpz
rpz

Reputation: 27

recovery user ID with flutter

I have a problem with my redirection. I would like to redirect my user if it is new to my registerscreen, if not new to my topnavigationscreen.

To check if the user exists I would like to get some information from "cloud firestore" which is created in my registerscreen. But I can't get them back.

My little code:

 void registergoogleUser() async {
    await _userProvider
        .registergoogleUser( _scaffoldKey)
        .then((response) async {
      if (response is Success<UserCredential>) {
        Future<DocumentSnapshot> getUser(String userId) async {
          final FirebaseFirestore instance = FirebaseFirestore.instance;
          print (await instance.collection('users')?.doc(userId)?.get());// for test
          (await instance.collection('users')?.doc(userId)?.get());
        }
        print (getUser);
        if (await getUser != null) {
          Navigator.of(context).pushNamedAndRemoveUntil(
              TopNavigationScreen.id, (route) => false);
        } else {
          Navigator.pop(context);
          Navigator.pushNamed(context, RegisterScreen.id);
        }
        }});
  }

But my "run" return this:

[ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Bad state: cannot get a field on a DocumentSnapshotPlatform which does not exist

and my

print (instance.collection('users').doc(userId).get());

return this:

I/flutter (25671): Closure: (String) => Future

you can see my code (for variables and other) here:

Upvotes: 1

Views: 144

Answers (2)

dariowskii
dariowskii

Reputation: 315

Apart from this, to check if a user exists you can use FirebaseAuth like this:

void _checkIfExsist(String email) async {
    // final _auth = FirebaseAuth.instance;
    final _list = await _auth.fetchSignInMethodsForEmail(email);
    if(_list.isEmpty){
      //User not registered
    } else {
      //User registered
    }
  }

EDIT

As said by other user before, you need to await Future:

void registergoogleUser() async {
    await _userProvider
        .registergoogleUser( _scaffoldKey)
        .then((response) async {
          if (response is Success<UserCredential>) {
            // You need to await the Futures!
            Future<DocumentSnapshot> getUser(String userId) async {
              final FirebaseFirestore instance = FirebaseFirestore.instance;
              print (instance.collection('users')?.doc(userId)?.get()); //print for test
              return instance.collection('users')?.doc(userId)?.get();
            }
            final result = await getUser(userId);
            if (result != null) {
              Navigator.of(context).pushNamedAndRemoveUntil(
                  TopNavigationScreen.id, (route) => false);
            } else {
              Navigator.pop(context);
              Navigator.pushNamed(context, RegisterScreen.id);
            }
          }
        }
      );
  }

Upvotes: 0

Simon Sot
Simon Sot

Reputation: 3136

Here

print(await instance.collection('users').doc(userId).get())

you are using Future as synchronous call. You must await for value then if docs not null use get on it. By the way in cases like this use ?. operator to be null-safe, like

print(await instance.collection('users')?.doc(userId)?.get())

Upvotes: 1

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