在应用程序启动时发出Firestore请求并保存它(Flutter)

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

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

  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Firestore Demo',
      home: Scaffold(
        appBar: AppBar(
          title: Text('Firestore Demo'),
        ),
        body: Center(
          child: RaisedButton(
            child: Text('Fetch and Save Data'),
            onPressed: () {
              fetchData();
              saveData();
            },
          ),
        ),
      ),
    );
  }

  void fetchData() async {
    CollectionReference users = FirebaseFirestore.instance.collection('users');
    QuerySnapshot querySnapshot = await users.get();
    querySnapshot.docs.forEach((doc) {
      print(doc.data());
    });
  }

  void saveData() async {
    CollectionReference users = FirebaseFirestore.instance.collection('users');
    await users.doc('user1').set({
      'name': 'John Doe',
      'email': 'johndoe@example.com',
    });
  }
}