StreamBuilder 未更新 Flutter 中的 Firestore 数据

Question

I'm making a Flutter application and I'm trying to get the user's data in the app.

So basically, the user registers with his info (name, email, password), and this data is displayed in a ProfilePage when he's logged in.

According to Firestore documentation, I'm supposed to use a StreamBuilder to get his data.

At this point, everything works fine.

The problem is that when the user logs out and another user logs in, the ProfilePage displays the precedent user's data (the user logged out).

Only if I restart the app, then I'm getting the right data.

Here's my ProfilePage :

class UserInformation extends StatefulWidget {
  @override
  _UserInformationState createState() => _UserInformationState();
}

class _UserInformationState extends State<UserInformation> {

  final _uid = FirebaseAuth.instance.currentUser!.uid;

  final Stream<QuerySnapshot> _usersStream =
      FirebaseFirestore.instance.collection('Users')
        .doc(_uid)
        .collection('UserData')
        .snapshots();

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
       key: Key(_uid),
      stream: _usersStream,
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError) {
          return const Text('Something went wrong');
        }

        if (snapshot.connectionState == ConnectionState.waiting) {
          return const Text("Loading");
        }

        return ListView(
          children: snapshot.data!.docs
              .map((DocumentSnapshot document) {
                Map<String, dynamic> data =
                    document.data()! as Map<String, dynamic>;
                return ListTile(
                  title: Text(data['full_name']),
                  subtitle: Text(data['company']),
                );
              })
              .toList()
              .cast(),
        );
      },
    );
  }
}

I see that this is a question asked several times on SO but I couldn't find a good solution. I tried to add a unique key in the StreamBuilder but it doesn't solve the problem.

I also saw the use of didUpdateWidget but I don't understand how to use it.

Answer 1

try replace this:

  final _uid = FirebaseAuth.instance.currentUser!.uid;

with this:

  late final _uid;
  @override
  initState() {
  _uid = FirebaseAuth.instance.currentUser!.uid;
  super.initState();
 }

then restart your app again, and simulate your behavior

Answer 2

reload the current user details with:

await FirebaseAuth.instance.currentUser!.reload();

I will say that the best place to put it, is to do it before returning that stream, first make the Stream a method:

Stream<QuerySnapshot> myStream() async {
await FirebaseAuth.instance.currentUser!.reload();
final _uid = FirebaseAuth.instance.currentUser!.uid;
return FirebaseFirestore.instance.collection('Users')
    .doc(_uid)
    .collection('UserData')
    .snapshots();
}

then in the StreamBuilder , set stream property to:

stream: myStream(),

Answer 3

I found the solution:

I simply moved the stream inside the build and the problem is solved !

After edit:

class UserInformation extends StatefulWidget {
  @override
  _UserInformationState createState() => _UserInformationState();
}

class _UserInformationState extends State<UserInformation> {

  @override
  Widget build(BuildContext context) {

 final _uid = FirebaseAuth.instance.currentUser!.uid;

  final Stream<QuerySnapshot> _usersStream =
      FirebaseFirestore.instance.collection('Users')
        .doc(_uid)
        .collection('UserData')
        .snapshots();

    return StreamBuilder<QuerySnapshot>(
       key: Key(_uid),
      stream: _usersStream,
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError) {
          return const Text('Something went wrong');
        }

        if (snapshot.connectionState == ConnectionState.waiting) {
          return const Text("Loading");
        }

        return ListView(
          children: snapshot.data!.docs
              .map((DocumentSnapshot document) {
                Map<String, dynamic> data =
                    document.data()! as Map<String, dynamic>;
                return ListTile(
                  title: Text(data['full_name']),
                  subtitle: Text(data['company']),
                );
              })
              .toList()
              .cast(),
        );
      },
    );
  }
}
```