Flutter等待Firestore完成

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Firestore Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Future<void> fetchData() async {
    // 等待Firestore读取完成
    DocumentSnapshot snapshot = await FirebaseFirestore.instance
        .collection('users')
        .doc('abc123')
        .get();

    // 打印读取的数据
    print(snapshot.data());
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Firestore Demo'),
      ),
      body: Center(
        child: ElevatedButton(
          child: Text('Fetch Data'),
          onPressed: fetchData,
        ),
      ),
    );
  }
}

dependencies:
  flutter:
    sdk: flutter
  cloud_firestore: ^2.5.3