Future builder returning length as null - flutter

Question

I am retreiving data from cloud firestore and using Future builder and Listview Builder to display the data. But i am getting null values in the Listview builder i.e displaying the CircularProgressIndicator always.Can't figure out the problem.Any solution will be of great help.
The print(values) function prints out: [9,8] successfully
This is the code i implemented:
Future<List> getassignment() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
final name = prefs.getString('orgname') ?? '';
print(name);
var query = FirebaseFirestore.instance.collection('Org').doc(name).collection('Login').doc(FirebaseAuth.instance.currentUser.uid);
query.snapshots().forEach((doc) {
List values = List.from(doc.data()['fields']['class']);
print(values);
return values;
});
}
// void getlist() async{
// await getassignment();
// }
#override
void initState() {
// getlist();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Color(0xFF1976D2),
body: FutureBuilder(
future: getassignment(),
builder: (context,snapshot){
List list = snapshot.data;
if (!snapshot.hasData) {
return Center(child: CircularProgressIndicator());
} else{
return Container(
child: ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (context, position) {
return GestureDetector(
onTap: (){
Navigator.of(context).push(MaterialPageRoute<Null>(
builder: (BuildContext context){
return new SubjectList(
clas: list[position].toString(),
);
}
));
},
child: Card(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Text(list[position].toString(), style: TextStyle(fontSize: 22.0),),
),
),
);
},
),
);
}
},
),
);
}

Answer 1

You are assigning and returning data inside of foreach loop. So that won't return anything.
// try adding await in this line.
var query = await FirebaseFirestore.instance.collection('Org').doc(name).collection('Login').doc(FirebaseAuth.instance.currentUser.uid);
List values = query.snapshots().forEach((doc) => List.from(doc.data()['fields']['class']));
print(values);
return values;
You need to do something like this.