知道这个问题的函数需要返回一个小部件，但现在确定我如何才能解决这个问题在我的代码，感谢帮助

class PhotoGrid extends StatefulWidget {
  const PhotoGrid({super.key});

  @override
  State<PhotoGrid> createState() => _PhotoGridState();
}

class _PhotoGridState extends State<PhotoGrid> {
  final Stream<QuerySnapshot> _photoStream =
      FirebaseFirestore.instance.collection('photos').snapshots();

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: StreamBuilder<QuerySnapshot>(
          stream: _photoStream,
          builder:
              (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
            if (snapshot.hasError) {
              return const Text('Something went wrong');
            }

            if (snapshot.connectionState == ConnectionState.waiting) {
              return const Text("Loading");
            }

            return GridView.builder(
              gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
                maxCrossAxisExtent: 120,
                crossAxisSpacing: 20,
                childAspectRatio: 3 / 2,
                mainAxisSpacing: 20,
              ),
              itemCount: snapshot.data!.docs.length,
              itemBuilder: (context, index) {
                var data = snapshot.data!.docs
                    .map((DocumentSnapshot documents) {
                      var data = documents.data()! as Map<String, dynamic>;
                      return Container(
                        decoration: BoxDecoration(
                          image: DecorationImage(
                            image: NetworkImage('${data['ImgUrl']}'),
                          ),
                        ),
                      );
                    })
                    .toList()
                    .cast();
              },
            );
          },
        ),
      ),
    );
  }
}
enter code here

知道函数需要返回一个小部件的问题，但现在确定如何在我的代码中解决这个问题，感谢帮助知道函数需要返回一个小部件的问题，但现在确定如何在我的代码中解决这个问题，感谢帮助