Flutter and Cloud Firestore fetch issue - database

Question

I have a problem with Flutter and Cloud Firestore from Firebase.
I already can add data to the database but I can't fetch it, because every time I call my method I get null back.
Here is my code:
dynamic getFromDatabase(String path, String item) {
DocumentReference _docu = Firestore.instance.document('$path');
var data;
_docu.get().then((datasnapshot) {
if(datasnapshot.exists){
data = datasnapshot.data['$item'];
}
});
return data;
}
This is where I call the method:
print((await getFromDatabase("User/$_uid","Vorname")));
And the error:
I/flutter (26289): null

Answer 1

I've not used Firestore before. Only the normal database of firebase. But I think this is a async timing issue. It looks like it's returning null before it can complete the datasnapshot. (PS. datasnapshot is spelled wrong). Try something like this. Like I said. Not sure if it works.
Future<String> getFromDatabse(String path, String item){
DocumentReference _docu = Firestore.instance.document(path);
_docu.get().then((datasnapchot){
if(datasnapchot.exists){
return datasnapchot.data[item];
}
});
}
And when calling the method. Do this.
String getData = await getFromDatabse(path, item);
(PS also database is spelled wrong haha)

Answer 2

A good option is using the FutureBuilder widget.
You can use it inside a StatelessWidget, avoiding to implemente a StatefulWidget
FutureBuilder(
future: Firestore.instance.document(path).get(),
builder: (context, snapshot) {
if (snapshot.connectionState != ConnectionState.done) {
return CircularProgressIndicator();
}
if (snapshot.hasError) {
return Text('Something went wrong.');
}
DocumentSnapshot docSnap = snapshot.data as DocumentSnapshot;
return Text(docSnap.data['doc_field']);
}
)