Flutter Firebase fetch.then is not working with initState - firebase

Question

I've tried to to fetch data from my firebase realtime database and it worked for antoher app with the same source code. But this time i think something doesn't work with my .then function. I do not receive data for building, but then 5 seconds later there is the data in my console. I know that this is asynchronous and that normally it would work, it shloud build after the init State method. Is there sth i've missed? Thx for help :)
class _HomeState extends State<Home> {
ScrollController _scrollController = new ScrollController();
List<Map<dynamic, dynamic>> _lists = [];
Future fetchList() async {
dbRef.once().then((DataSnapshot snapshot) {
Map<dynamic, dynamic> values = snapshot.value;
print(values);
_lists.clear();
values.forEach((key, values) {
_lists.add(values);
});
print(_lists);
});
return _lists;
}
final dbRef = FirebaseDatabase.instance.reference().child("spieler");
final dbRefpreise = FirebaseDatabase.instance.reference().child("preise");
#override
void initState() {
fetchList().then((value) {
setState(() {
_lists.addAll(value);
});
});
super.initState();
}

Answer 1

You need to await the method but since you cant await and async in iniState youll have to do this.
#override
void initState() {
getDataList();
super.initState();
}
void getDataList() async {
await fetchList().then((value) {
setState(() {
_lists.addAll(value);
});
});
}
Future fetchList() async {
await dbRef.once()..... //some code
}