Flutter: Firestore Get User uid inside StreamBuilder - firebase

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,
);
}
},
)

Answer 1

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...');
}

Answer 2

THANK YOU GUYS!
I was looking for this for too long now. I had the "problem" that I was recording the senderUID for a sent message only, but of course wanted the Name being displayed in the "sentFrom" field. So I had to query Firestore for the UID and pull out the email. My solution:
FutureBuilder<QuerySnapshot>(
future: _firestore.collection("users").get(),
builder: (context, futureSnapshot) {
if (!futureSnapshot.hasData) {
return Center(
child: CircularProgressIndicator(),
);
}
Map<String, String> users = {};
final userData = futureSnapshot.data.docs;
for (var user in userData) {
users[user.id] = user.data()["email"];
}
return StreamBuilder<QuerySnapshot>(
stream: _firestore.collection("messages").snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return Center(
child: CircularProgressIndicator(),
);
}
// ignore: missing_return
final messages = snapshot.data.docs;
List<Widget> messageWidgets = [];
for (var message in messages) {
final messageText = message.data()["text"];
final messageEmail = users[message.data()["senderUID"]];
messageWidgets
.add(Text("$messageText from $messageEmail"));
}
return Column(children: messageWidgets);
},
);
},
),
I just created a map from the data and used it inside the stream builder. Is there maybe a better solution?