Flutter:显示firestore中的所有用户

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

void main() async {
  // 初始化Firebase
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();

  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Firestore Users',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: UsersScreen(),
    );
  }
}

class UsersScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Firestore Users'),
      ),
      body: StreamBuilder(
        stream: FirebaseFirestore.instance.collection('users').snapshots(),
        builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
          if (snapshot.hasError) {
            return Text('Error: ${snapshot.error}');
          }

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

          return ListView(
            children: snapshot.data.docs.map((DocumentSnapshot document) {
              Map<String, dynamic> user = document.data() as Map<String, dynamic>;

              return ListTile(
                title: Text(user['name']),
                subtitle: Text(user['email']),
              );
            }).toList(),
          );
        },
      ),
    );
  }
}