如何使用flutter检索Firestore数据

dependencies:
  flutter:
    sdk: flutter
  cloud_firestore: ^2.5.3

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

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

final collectionRef = FirebaseFirestore.instance.collection('users');
final snapshot = await collectionRef.get();
snapshot.docs.forEach((doc) {
  print('User ID: ${doc.id}');
  print('Name: ${doc['name']}');
  print('Age: ${doc['age']}');
});

final collectionRef = FirebaseFirestore.instance.collection('users');
final snapshot = await collectionRef.where('age', isGreaterThan: 18).get();
snapshot.docs.forEach((doc) {
  print('User ID: ${doc.id}');
  print('Name: ${doc['name']}');
  print('Age: ${doc['age']}');
});