Flutter /Firebase - Accessing the realtime database - firebase

Question

In my flutter project, I need to access the realtime database to get the name of the user when they create a post. This is the code I'm working with:
class PostScreen extends StatelessWidget {
static const String idScreen = 'post';
final String name1 = FirebaseDatabase.instance
.reference()
.child('users')
.child(FirebaseAuth.instance.currentUser.uid)
.child('name1')
.toString();
final String name2 = FirebaseDatabase.instance
.reference()
.child('users')
.child(FirebaseAuth.instance.currentUser.uid)
.child('name2')
.toString();
#override
Widget build(BuildContext context) {
return Scaffold(
body: FlatButton(
child: Text('Create Post'),
onPressed: () {
MainScreen.posts.add(Post(
name1: name1,
name2: name2,
));
Navigator.pushNamed(context, MainScreen.idScreen);
},
),
);
}
}
class Post extends StatelessWidget {
String name1 = '';
String name2 = '';
Post({#required name1, #required name2});
#override
Widget build(BuildContext context) {
return Card(
child: Row(
children: [
Text(name1),
Text(" and "),
Text(name2),
],
),
);
}
}
What happens though is that the name is left blank and just creates a card that says " and ". What could I be doing wrong?

Answer 1

Your code doesn't read anything from the database yet. For that to happen you need to call the once() stream, or listen to the onValue or onChild... streams.
I also recommend simplifying your problem before continuing. So instead of reading the data for the current user (which requires that you have a current user), simply write some hard-coded data at a known location in the database and read that first. That should look something like this:
final DatabaseReference ref = FirebaseDatabase.instance
.reference()
.child('test');
#override
Widget build(BuildContext context) {
return StreamBuilder(
stream: ref.onValue,
builder: (BuildContext context, snapshot) {
if(snapshot.hasData) => return Text(snapshot.value);
else if(snapshot.hasError) => return Text("Error");
else return Text("No data (yet)");
}
);
}
There may be syntax errors in this code, so treat it as an example of an approach instead of a copy/paste solution please. If you find any of such errors, please try to solve them on your own - and edit the answer with any fixes.
Also see:
How To Use Firebase RTDB with Flutter Stream
more of these search results

Answer 2

You should be able to do something like this:
DatabaseReference myRef = FirebaseDatabase.instance
.reference()
.child('users')
.child(FirebaseAuth.instance.currentUser.uid)
.child('name1');
StreamBuilder(
stream: myRef.onValue,
builder: (context, AsyncSnapshot<Event> snap) {
if (snap.hasData && !snap.hasError && snap.data.snapshot.value != null) {
// Handle snapshot data
}
}
If you don't need to continue getting changes from the location you can probably use a future builder and .once() method. Don't have experience with that myself though.