Wait a function to be done in ListView - flutter

Question

I need to wait my function to be done in a ListView because of a Firestore request. I tried using Future.wait() but it does not work.
FutureBuilder<QuerySnapshot>(
future: FirebaseFirestore.instance
.collection('Statements')
.where('userID',isEqualTo: context.watch<User>().uid)
.get(),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot){
if (snapshot.hasError) {return Text("Erreur");}
if (snapshot.connectionState == ConnectionState.waiting) {
return Text("Loading");}
return Expanded(
child:ListView.builder(
itemCount: snapshot.data.docs.length,
itemBuilder: (context, index) {
DocumentSnapshot document = snapshot.data.docs[index];
Future.wait([getStatementData(document)]);
return StatementCard(statement:selectedStatement,
accommodation : relatedAccommodation,
owner : relatedOwner);
},
)
Here is the function called :
Future getStatementData(document) async {
selectedStatement = Statement.fromFirebase(document);
document.data()["accommodation"].get().then((value) {
relatedAccommodation = Accommodation.fromFirebase(value);});
await FirebaseFirestore.instance
.collection('Owners')
.doc(document["ownerList"][0])
.get().then((value) {
print(value.data());
relatedOwner = Owner.fromFirebase(value);
});
}
Should I use another future builder ?

Answer 1

You should do it like this by returning another Future Builder inside :
ListView.builder(
itemCount: snapshot.data.docs.length,
itemBuilder: (context, index) {
DocumentSnapshot document = snapshot.data.docs[index];
return FutureBuilder(
future: getStatementData(document) ,
builder: (context, snapshot) {
return snapshot.connectionState == ConnectionState.done
? StatementCard(statement:selectedStatement,
accommodation : relatedAccommodation,
owner : relatedOwner);
: Container();
);
},
)

Answer 2

I think you just missed a simple thing, FutureBuilder also has a connectionstate.done state which you can access. This waits until your future function is Done.
return FutureBuilder(
future: yourFunction,
builder: (context, snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
return Center(child: Text('No status',);
break;
case ConnectionState.waiting:
return Center(child: CircularProgressIndicator());
break;
case ConnectionState.done:
return Text('Im done!') // Your listviewbuilder comes here
break;
default:
}
},
),
doc: https://api.flutter.dev/flutter/widgets/FutureBuilder-class.html
example FutureBuilder with ListViewBuilder: https://medium.com/nonstopio/flutter-future-builder-with-list-view-builder-d7212314e8c9
[...]connectionState.done = [future] is not null, and has completed. If the future completed successfully, the [AsyncSnapshot.data] will be set to the value to which the future completed. If it completed with an error, [AsyncSnapshot.hasError] will be true and [AsyncSnapshot.error] will be set to the error object.[...]