字符串能否与firebase实时数据库中的键值进行比较？

Question

我是新的颤振和火力基地，并试图显示当前用户的数据，已登录。我自己尝试过各种方法，比如将当前用户的电子邮件存储在字符串变量上，并将其与他们的电子邮件键进行比较，但无法找到如何做到这一点。

是否有一种方法可以将快照作为仅登录用户数据的输出？

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    import 'package:firebase_database/firebase_database.dart';
import 'package:firebase_database/ui/firebase_animated_list.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:helloworld/tictactoe.dart';
import 'package:helloworld/numbergame.dart';
import 'package:helloworld/profile.dart';

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      // Remove the debug banner
      debugShowCheckedModeBanner: false,
      title: 'Search',
      home: Search(),
    );
  }
}

class Search extends StatefulWidget {
  const Search({Key? key}) : super(key: key);
  static const String id = 'search';
  @override
  _SearchState createState() => _SearchState();
}

class _SearchState extends State<Search> with AutomaticKeepAliveClientMixin {
  final dbRef = FirebaseDatabase.instance.ref().child("insertdata");
  List<Map<dynamic, dynamic>> lists = [];

  final _auth = FirebaseAuth.instance;
  late String? userEmail;
  void getCurrentUserEmail() async {
    final user = await _auth.currentUser;
    userEmail = user!.email;
  }
  void initState() {
    super.initState();
    getCurrentUserEmail();
  }
  @override
  Widget build(BuildContext context) {
    super.build(context);
    //btmnavbar

    return Scaffold(
      resizeToAvoidBottomInset: false,
      body: FutureBuilder<DatabaseEvent>(
          future: dbRef.once(),
          builder: (context, AsyncSnapshot<DatabaseEvent> snapshot) {
            if (snapshot.hasData) {
              lists.clear();
              Map<dynamic, dynamic> values = snapshot.data!.snapshot.value as Map<dynamic, dynamic>;
              values.forEach((key, values) {
                lists.add(values);
              });
              return new ListView.builder(
                  shrinkWrap: true,
                  itemCount: lists.length,
                  itemBuilder: (BuildContext context, int index) {
                    return Card(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: <Widget>[
                          Text("Name: " + lists[index]["Email"]),
                          Text("Age: " + lists[index]["First Name"]),
                          Text("Type: " + lists[index]["Last Name"]),
                        ],
                      ),
                    );
                  });
            }
            return CircularProgressIndicator();
          }),
    );
  }

  @override
  // TODO: implement wantKeepAlive
  bool get wantKeepAlive => true;
}

Answer 1

如果您有用户的电子邮件地址，您可以使用一个查询来选择在其Email属性中具有该值的节点：

future: dbRef.orderByChild("Email").equalTo("hiba@gmail.com").once(),

或者，如果您有一个带有电子邮件地址的变量userEmail：

future: dbRef.orderByChild("Email").equalTo(userEmail).once(),

还请参阅实时数据库中有关排序和过滤数据的Firebase文档。