How to use UID to acces database in Flutter? - dart

Question

i am using the following function to retrive the UID:
FirebaseAuth auth = FirebaseAuth.instance;
getUID() async {
final FirebaseUser user = await auth.currentUser();
final uid = user.uid;
return uid;
}
After that, i would like to use the UID to acces the right database-doc:
return new StreamBuilder(
stream: Firestore.instance.collection('users').document(getUID()).snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new Text("Loading");
}
var userDocument = snapshot.data;
But i get the error
Future<dynamic> is not a subtype of type "string"
What is the right way to do it?
FULL CODE
class Settings extends StatelessWidget{
FirebaseAuth auth = FirebaseAuth.instance;
getUID() async {
final FirebaseUser user = await auth.currentUser();
final uid = user.uid;
return uid;
}
static GlobalKey<FormState> _formKey = new GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Indstillinger"),
),
body: _buildSetting(context),
);
}
Widget _buildSetting(BuildContext context) {
return new StreamBuilder(
stream: Firestore.instance.collection('users').document(getUID()).snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new Text("Loading");
}
var userDocument = snapshot.data;

Answer 1

You need to use stateful widget, like
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
class Settings extends StatefulWidget {
#override
_SettingsState createState() {
return _SettingsState();
}
}
class _SettingsState extends State<Settings> {
FirebaseUser user;
String error;
void setUser(FirebaseUser user) {
setState(() {
this.user = user;
this.error = null;
});
}
void setError(e) {
setState(() {
this.user = null;
this.error = e.toString();
});
}
#override
void initState() {
super.initState();
FirebaseAuth.instance.currentUser().then(setUser).catchError(setError);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Indstillinger"),
),
body: user != null ? _buildSetting(context) : Text("Error: $error"),
);
}
Widget _buildSetting(BuildContext context) {
return new StreamBuilder(
stream: Firestore.instance.collection('users').document(user.uid).snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new Text("Loading");
}
var userDocument = snapshot.data;
// User userDocument here ..........
return new Text(userDocument.toString());
});
}
}

Answer 2

You're passing the function without actually awaiting for it to return. You could store the returned value in a variable before calling StreamBuilder.
final documentId = await getUID();
return new StreamBuilder(
stream: Firestore.instance.collection('users').document(documentId).snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new Text("Loading");
}
var userDocument = snapshot.data;