如何将 textformfield 值与列表的所有项目进行比较？答案

【问题标题】：How to compare a textformfield value to all items of a List?如何将 textformfield 值与列表的所有项目进行比较？
【发布时间】：2022-08-14 06:53:19
【问题描述】：

我有一个使用 http.get 方法从数据库中检索的项目列表。我需要创建一个验证器，仅当键入的值等于列表中的至少一个值时才允许用户提交。

示例：列表为：[{name: Peter, email: peter@gmail.com}{name: Mathew, email: mtw@gmail.com}]。然后我有两个 textFormFields，一个用于 NAME，另一个用于 EMAIL。因此，如果用户类型的 NAME 和 EMAIL 匹配列表中的任何项目，则用户可以提交。我创建了 http.get 方法并创建了 TextFormfields，但我不知道如何创建验证器。

这是处方代码：

// ignore_for_file: no_leading_underscores_for_local_identifiers, prefer_typing_uninitialized_variables

import \'dart:convert\';
import \'package:apetit_project/components/teste_app_users_item.dart\';
import \'package:apetit_project/models/app_user.dart\';
import \'package:firebase_auth/firebase_auth.dart\';
import \'package:flutter/material.dart\';
import \'../models/auth_form_data.dart\';
import \'package:http/http.dart\' as http;

import \'../models/user_data.dart\';

class AuthForm extends StatefulWidget {
  final void Function(AuthFormData) onSubmit;

  const AuthForm({
    Key? key,
    required this.onSubmit,
  }) : super(key: key);

  @override
  State<AuthForm> createState() => _AuthFormState();
}

class _AuthFormState extends State<AuthForm> {
  TextEditingController _emailController = TextEditingController();
  TextEditingController _passwordController = TextEditingController();
  final _formKey = GlobalKey<FormState>();
  final _formData = AuthFormData();
  List<dynamic> _teste = [];
  List<dynamic> get teste => [..._teste];
  final _url = \'URL\';

  @override
  void dispose() {
    _emailController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  bool isLogin = true;
  late String title;
  late String actionButton;
  late String toggleButton;

  void _submit() {
    final isValid = _formKey.currentState?.validate() ?? false;
    if (!isValid) return;

    widget.onSubmit(_formData);
  }

  Future<void> _loadUsers() async {
    final response = await http.get(
      Uri.parse(\'http://172.16.30.120:8080/ords/apiteste/integrafoods/users\'),
      headers: <String, String>{
        \'Content-Type\': \'application/json; charset=UTF-8\',
      },
    );
    if (response.body == \'null\') return;
    final data = jsonDecode(response.body)[\'items\'] as List?;

    if (data != null) {
      // _teste = data;
      _teste = data.map((e) => MyItem.fromMap(e)).toList();
      print(data);
    }
    // print(_teste.toList());
  }

  @override
  _initState() {
    _loadUsers();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    // print(_teste);
    return Scaffold(
      body: Container(
        decoration: const BoxDecoration(
          image: DecorationImage(
            image: AssetImage(\'assets/images/Login.png\'),
            fit: BoxFit.cover,
            alignment: Alignment.center,
          ),
        ),
        child: Container(
          margin: const EdgeInsets.only(bottom: 20),
          child: Padding(
            padding: const EdgeInsets.all(20),
            child: Form(
              key: _formKey,
              child: Column(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  if (_formData.isSignup)
                    TextFormField(
                      key: const ValueKey(\'Nome\'),
                      initialValue: _formData.name,
                      onChanged: (name) => _formData.name = name,
                      decoration: InputDecoration(
                        enabledBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        focusedBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        focusedErrorBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        prefixIcon: Padding(
                          padding: const EdgeInsets.only(left: 18, right: 18),
                          child: Image.asset(
                            \'assets/images/password_icon.png\',
                            scale: 6,
                            color: Colors.black,
                          ),
                        ),
                        labelText: \'Nome\',
                        labelStyle: const TextStyle(color: Colors.black),
                      ),
                      keyboardType: TextInputType.emailAddress,
                    ),
                  const SizedBox(
                    height: 4,
                  ),
                  TextFormField(
                    // controller: _emailController,
                    key: const ValueKey(\'Email\'),
                    initialValue: _formData.email,
                    onChanged: (email) => _formData.email = email,
                    decoration: InputDecoration(
                      enabledBorder: OutlineInputBorder(
                          borderSide: const BorderSide(color: Colors.black),
                          borderRadius: BorderRadius.circular(30)),
                      focusedBorder: OutlineInputBorder(
                          borderSide: const BorderSide(color: Colors.black),
                          borderRadius: BorderRadius.circular(30)),
                      focusedErrorBorder: OutlineInputBorder(
                          borderSide: const BorderSide(color: Colors.black),
                          borderRadius: BorderRadius.circular(30)),
                      prefixIcon: Image.asset(
                        \'assets/images/email_icon.png\',
                        scale: 6,
                        color: Colors.black,
                      ),
                      labelText: \'Email\',
                      labelStyle: const TextStyle(color: Colors.black),
                    ),
                    validator: (_email) {
                      final email = _email ?? \'\';
                      if (!email.contains(\'@\')) {
                        return \'E-mail informado não é válido.\';
                      }
                      return null;
                    },
                    keyboardType: TextInputType.emailAddress,
                  ),
                  const SizedBox(
                    height: 4,
                  ),
                  TextFormField(
                    // controller: _passwordController,
                    key: const ValueKey(\'password\'),
                    initialValue: _formData.password,
                    onChanged: (password) => _formData.password = password,
                    style: const TextStyle(color: Colors.black),
                    obscureText: true,
                    decoration: InputDecoration(
                        enabledBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        focusedBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        errorBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        focusedErrorBorder: OutlineInputBorder(
                            borderSide: const BorderSide(color: Colors.black),
                            borderRadius: BorderRadius.circular(30)),
                        prefixIcon: Padding(
                          padding: const EdgeInsets.only(left: 18, right: 18),
                          child: Image.asset(
                            \'assets/images/password_icon.png\',
                            scale: 6,
                            color: Colors.black,
                          ),
                        ),
                        labelText: \'Senha\',
                        labelStyle: const TextStyle(color: Colors.black)),
                    validator: (_password) {
                      final password = _password ?? \'\';
                      if (password.length < 6) {
                        return \'Senha deve ter no mínimo 6 caracteres\';
                      }
                      return null;
                    },
                  ),
                  const SizedBox(
                    height: 10,
                  ),
                  ElevatedButton(
                    onPressed: _loadUsers,
                    child: Text(\'teste\'),
                  ),
                  // Expanded(
                  //   child: ListView.builder(
                  //     itemBuilder: (ctx, index) {
                  //       return Card(
                  //           child: ClipRRect(child: MyItemItem(_teste[index])));
                  //     },
                  //     itemCount: _teste.length,
                  //   ),
                  // ),
                  SizedBox(
                    width: double.infinity,
                    child: ElevatedButton(
                      // onPressed: _signInUser,
                      onPressed: _submit,
                      style: ButtonStyle(
                        shape: MaterialStateProperty.all(RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(30),
                        )),
                        padding:
                            MaterialStateProperty.all(const EdgeInsets.all(15)),
                        backgroundColor: MaterialStateProperty.all(
                            Theme.of(context).colorScheme.secondary),
                      ),
                      child: Text(
                        _formData.isLogin ? \'Entrar\' : \'Cadastrar\',
                        style: const TextStyle(
                            color: Colors.black,
                            fontFamily: \'Raleway\',
                            fontWeight: FontWeight.bold),
                      ),
                    ),
                  ),
                  TextButton(
                    onPressed: () {
                      setState(() {
                        _formData.toggleAuthMode();
                      });
                    },
                    child: Text(
                      _formData.isLogin
                          ? \'Criar uma nova conta?\'
                          : \'Já possui conta?\',
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

  // Future _signInUser() async {
  //   await FirebaseAuth.instance.signInWithEmailAndPassword(
  //     email: _emailController.text,
  //     password: _passwordController.text,
  //   );
  // }
}

这是“我的项目”类

import \'dart:convert\';

class MyItem {
  final int id;
  final String email;
  final String? cpf;
  MyItem({
    required this.id,
    required this.email,
    required this.cpf,
  });

  Map<String, dynamic> toMap() {
    final result = <String, dynamic>{};

    result.addAll({\'sequencia\': id});
    if (email != null) {
      result.addAll({\'email\': email});
    }
    if (cpf != null) {
      result.addAll({\'cpf\': cpf});
    }

    return result;
  }

  factory MyItem.fromMap(Map<String, dynamic> map) {
    return MyItem(
      id: int.tryParse(map[\'sequencia\'].toString()) ?? 0,
      email: map[\'email\'],
      cpf: map[\'cpf\'],
    );
  }

  String toJson() => json.encode(toMap());

  factory MyItem.fromJson(String source) => MyItem.fromMap(json.decode(source));
}

我该如何解决？

请考虑在您的帖子上使用英语拼写检查器。大多数浏览器都内置了一个。

标签： flutter forms dart http get

【解决方案1】：

以下应该可以解决问题。对name 执行相同的操作，您就可以开始了。

validator: (_email) {
  final email = _email ?? '';
  if (!email.contains('@')) {
    return 'E-mail informado não é válido.';
  }
  if (!_teste.any((item) => item.email == email)) {  // <- Here
    return 'E-mail já cadastrado.';                  // <- Here
  }
  return null;
},

【讨论】：