如何在collection.document.collection.document() flutter dart中检查firebase中的特定值

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 FirebaseFirestore firestore = FirebaseFirestore.instance;

CollectionReference collectionRef = firestore.collection('your_collection');

DocumentReference documentRef = collectionRef.doc('your_document');

DocumentSnapshot documentSnapshot = await documentRef.get();

if (documentSnapshot.exists) {
  // 获取特定字段的值
  var specificValue = documentSnapshot['your_field'];
  // 进行你的逻辑操作
} else {
  // 文档不存在，执行其他逻辑
}

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());
}

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

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Firebase Demo'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Check Value'),
          onPressed: () async {
            final FirebaseFirestore firestore = FirebaseFirestore.instance;
            CollectionReference collectionRef = firestore.collection('your_collection');
            DocumentReference documentRef = collectionRef.doc('your_document');
            DocumentSnapshot documentSnapshot = await documentRef.get();

            if (documentSnapshot.exists) {
              var specificValue = documentSnapshot['your_field'];
              print('Specific Value: $specificValue');
            } else {
              print('Document does not exist');
            }
          },
        ),
      ),
    );
  }
}