List contains Instance of 'Future<dynamic>' - flutter

Question

I have this code trying to query some data from Firestore using GeoFlutterFire, but for the sake of efficiency I want to fetch the list of ids only once, then use it to fetch the rest of the data from Firebase Database.
This is the code in question:
class _StartScreenState extends State<StartScreen> {
List ids = ['abc'];
#override
void initState() {
super.initState();
print('ids ${ids}');
}
_initState() async {
Firestore _firestore = Firestore.instance;
List ids1 = [];
Geoflutterfire geo = Geoflutterfire();
var location = new Location();
var pos = await location.getLocation();
GeoFirePoint center = geo.point(latitude: pos.latitude.toDouble(), longitude: pos.longitude.toDouble());
var collectionReference = _firestore.collection('locations');
var geoRef = geo.collection(collectionRef: collectionReference);
return ids1.add(geoRef.within(center: center, radius: 50, field: 'position', strictMode: true).first.then((value) {
value.map((doc) {
if (doc.data.isNotEmpty) {
print('doooc id here ${doc['id']}');
ids1.add(doc['id']);
print(ids1);
}
}).toList();
setState(() {
ids = ids1;
print('setting state to ids ids print: ${ids.}');
});
}));
}
Like I said, my intent is to fetch the Ids and once I have the list check if there's some related data in Firebase, but I'm not sure this is the way I should do it and there's something that I don't know how to awoid; When I print the list I get the following result:
setting state to ids ids print: [Instance of 'Future',
3esdWesqrTD_123_3dssds3, sQWdsda23dsad_da21]
Can anyone tell me why I have this Instance of 'Future' in my List and how can avoid it, please?

Answer 1

I have not tried to run your code, but I suspect the issue starts with the statement
return ids1.add(geoRef.within(center: center, radius: 50, field: 'position', strictMode: true).first.then((value) {
As you can see, you are adding something ids1.add(...) that looks like it needs to await: geoRef.within(...).first.(...). I don't find the ids1.add(...) call needed in the return statement. Try removing it, and see how it goes.