Flutter: Firestore Get User uid inside StreamBuilder

Question

I have an app which I want to display documents inside collection.. the collection reference is the uid of the user.

Is there a way to get current user uid and put this uid inside StreamBuilder in stream.

I have tried like so but it did not work and returned null:

class _MyAdsState extends State<MyAds> {
 final FirebaseAuth _auth = FirebaseAuth.instance;
Future getCurrentUser() async {
 final FirebaseUser user = await _auth.currentUser();
 final uid = user.uid;
 print(uid);
 return uid.toString();
}
@override
  Widget build(BuildContext context) {
   return Scaffold(
body: Column(
 Expanded(
          child: StreamBuilder<QuerySnapshot>(
            stream: Firestore.instance.collection("${getCurrentUser()}").snapshots(),
            builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> querySnapShot){
              if(querySnapShot.hasError){
                return Text('Some Error');
              }
              if(querySnapShot.connectionState == ConnectionState.waiting){
                return CircularProgressIndicator();
              }else{
                final list = querySnapShot.data.documents;
                return ListView.builder(
                    itemBuilder: (context, index){
                      return ListTile(
                        title: Text(list[index]["subject"]),
                        subtitle: Text(list[index]["category"]),
                      );
                    },
                  itemCount: list.length,
                );
              }
            },
          )

Solution

Getting the UID is an asynchronous operation, so requires a FutureBuilder.

If you want to use the UID to then build a stream, you'll need to have a FutureBuilder for the UID, and then inside of that a StreamBuilder for the stream from the database.

body: FutureBuilder(
  future: FirebaseAuth.instance.currentUser(),
  builder: (context, AsyncSnapshot<FirebaseUser> snapshot) {
    if (snapshot.hasData) {
      return StreamBuilder<QuerySnapshot>(
        stream: Firestore.instance.collection(snapshot.data.uid).snapshots(),
        builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> querySnapShot){
          ...
        },
      )
    }
    else {
      return Text('Loading user data...');
    }