用Flutter实现从Firestore加载数据时加载微调器的尝试

dependencies:
  cloud_firestore: ^2.5.3

import 'package:firebase_core/firebase_core.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: FirebaseFirestore.instance.collection('your_collection').snapshots(),
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError) {
          return Text('Error: ${snapshot.error}');
        }

        if (snapshot.connectionState == ConnectionState.waiting) {
          return CircularProgressIndicator();
        }

        return ListView(
          children: snapshot.data!.docs.map((DocumentSnapshot document) {
            Map<String, dynamic> data = document.data() as Map<String, dynamic>;
            return ListTile(
              title: Text(data['title']),
              subtitle: Text(data['subtitle']),
            );
          }).toList(),
        );
      },
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Firestore Demo',
      home: Scaffold(
        appBar: AppBar(
          title: Text('Firestore Demo'),
        ),
        body: MyWidget(),
      ),
    );
  }
}