How do I access the return data from a FutureBuilder?

Question

I am having a trouble accessing a single data from Firestore. Since accessing data from Firestore is a future whenever I try to call it from initState and setState it, it just prints null so I decided to use a FutureBuilder. So now, is it possible to access the return data from a FutureBuilder to the another page from page1.dart to page2.dart?

page1.dart

class FetchSingleData extends StatelessWidget {
  // I want to access this one
  String? uniqueHandler;

  FetchSingleData({super.key, this.uniqueHandler});

  Future<QuerySnapshot> fetchUniqueHanlder() async {
    return await FirebaseFirestore.instance.collection('users').get().then((value) => uniqueHandler = value.docs.first['userUniqueHandle']);
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
        future: fetchUniqueHanlder(),
        builder: (context, AsyncSnapshot<QuerySnapshot> snapshot) {
          if (snapshot.connectionState == ConnectionState.done) {
           // I want to access this one
            return Text(uniqueHandler!);
          }
          return CircularProgressIndicator();
        });
  }
}

here is the snippet/image of my firebase firestore.

I just wanna access the userUniqueHandler from my FutureBuilder(page1.dart) to my MainScreen(page2.dart)

Answer 1

the snapshot itself contains the data:

try this:

Future<QuerySnapshot> fetchUniqueHanlder() async {
  return await FirebaseFirestore.instance.collection('users').get();
}

@override
Widget build(BuildContext context) {
  return FutureBuilder(
    future: fetchUniqueHanlder(),
    builder: (context, AsyncSnapshot<QuerySnapshot> snapshot) {
      if (snapshot.connectionState != ConnectionState.done) {
        return CircularProgressIndicator();
      }
      if (snapshot.hasError || !snapshot.hasData) {
        return const Text("error");
      }

      final users = snapshot.data!;

      // your value
      uniqueHandler = users.docs.first['userUniqueHandle'];

      return Text(uniqueHandler!);
    },
  );
}