带有不匹配参数的闭包调用：函数'_RegisterState.build.<匿名闭包>'接收者：闭包：（字符串）=> Null

Posted 2023-04-19

【中文标题】带有不匹配参数的闭包调用：函数\'_RegisterState.build.<匿名闭包>\'接收者：闭包：（字符串）=> Null

【英文标题】：Closure call with mismatched arguments: function '_RegisterState.build.<anonymous closure>' Receiver: Closure: (String) => Null带有不匹配参数的闭包调用：函数'_RegisterState.build.<匿名闭包>'接收者：闭包：（字符串）=> Null

【发布时间】：2022-01-14 17:42:38

【问题描述】：

我不知道为什么会发生这个错误，完整的错误是：

Closure call with mismatched arguments: function '_RegisterState.build.<anonymous closure>'
Receiver: Closure: (String) => Null
Tried calling: _RegisterState.build.<anonymous closure>()
Found: _RegisterState.build.<anonymous closure>(String) => Null

我认为我在此处创建的可重用 Textformfield 中的错误代码 我的可重用 TextformField 代码是：

import 'package:flutter/material.dart';
import '../constants.dart';

class CustomTextField extends StatelessWidget 
const CustomTextField(
  Key? key, required this.hint, required this.icon, required this.onClick)
  : super(key: key);
final String hint;
final IconData icon;
final Function? onClick;

final OutlineInputBorder border = const OutlineInputBorder(
  borderRadius: BorderRadius.all(Radius.circular(20)),
  borderSide: BorderSide(color: Colors.white));

@override
Widget build(BuildContext context) 
return Padding(
  padding: const EdgeInsets.symmetric(horizontal: 30),
  child: TextFormField(
    onSaved: onClick!(),
    validator: (value) 
      if (value!.isEmpty) 
        switch (hint) 
          case 'Enter your email':
            return 'Enter your Email';
          case 'Enter your Name':
            return 'Enter a name';
          case 'Enter your password':
            return 'Enter a password';
          default:
            return 'Enter a value';
        
      
      if (hint == 'Enter your email' && !value.contains('@')) 
        return 'Enter valid email';
      
      if (hint == 'Enter your Name' && value.length < 3) 
        return 'Enter valid Name';
      
      if (hint == 'Enter your password' && value.length < 5) 
        return 'your password is weak';
      
    ,
    obscureText: hint == 'Enter your password' ? true : false,
    cursorColor: kMainColor,
    decoration: InputDecoration(
      hintText: hint,
      prefixIcon: Icon(
        icon,
        color: kMainColor,
      ),
      filled: true,
      fillColor: kSecondaryColor,
      focusedBorder: border,
      enabledBorder: border,
      border: border,
      ),
      ),
      );
      
      

我在 2 个屏幕中使用它来登录和注册

我的注册屏幕代码是：

import 'package:e_commerce/screens/login_screen.dart';
import 'package:e_commerce/servises/auth.dart';
import 'package:e_commerce/widgets/custom_input_field.dart';
import 'package:flutter/material.dart';

import '../constants.dart';

class Register extends StatefulWidget 
static String routName = 'Register';
const Register(Key? key) : super(key: key);

@override
_RegisterState createState() => _RegisterState();


class _RegisterState extends State<Register> 
String? name;
String? email;
String? password;
final GlobalKey<FormState> _key = GlobalKey();
@override
Widget build(BuildContext context) 
double height = MediaQuery.of(context).size.height;
return Scaffold(
  backgroundColor: kMainColor,
  body: SingleChildScrollView(
    child: Container(
      padding: const EdgeInsets.only(top: 100),
      alignment: Alignment.center,
      child: Form(
        key: _key,
        child: Column(
          children: [
            Image.asset("assets/images/icons/cart.png"),
            const Text('Buy now',
                style: TextStyle(
                    fontFamily: 'Corinthia',
                    color: Colors.black,
                    fontSize: 40,
                    fontWeight: FontWeight.bold)),
            SizedBox(
              height: height * 0.05,
            ),
            CustomTextField(
                onClick: (String value) 
                  if (_key.currentState!.validate()) 
                    name = value;
                  
                ,
                hint: 'Enter your Name',
                icon: Icons.person),
            SizedBox(
              height: height * 0.02,
            ),
            CustomTextField(
                onClick: (String value) 
                  if (_key.currentState!.validate()) 
                    email = value;
                  
                ,
                hint: 'Enter your email',
                icon: Icons.email_rounded),
            SizedBox(
              height: height * 0.02,
            ),
            CustomTextField(
                onClick: (String value) 
                  if (_key.currentState!.validate()) 
                    password = value;
                  
                ,
                hint: 'Enter your password',
                icon: Icons.lock),
            SizedBox(
              height: height * 0.05,
            ),
            MaterialButton(
              shape: const RoundedRectangleBorder(
                  borderRadius: BorderRadius.all(Radius.circular(8))),
              color: Colors.black,
              onPressed: () async 
                await MyAuth().sinIn(email!, password!);
              ,
              child: const Text(
                'Register',
                style: TextStyle(fontSize: 20, color: Colors.white),
              ),
            ),
            SizedBox(
              height: height * 0.02,
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                const Text(
                  'have an account?',
                  style: TextStyle(fontSize: 20),
                ),
                TextButton(
                  onPressed: () 
                    Navigator.of(context)
                        .pushReplacementNamed(LoginScreen.routName);
                  ,
                  child: const Text(
                    'Login  ',
                    style: TextStyle(fontSize: 20),
                  ),
                )
              ],
            )
          ],
        ),
      ),
    ),
  ),
  // ),
  );
 
 

我的登录屏幕代码是：

import 'package:e_commerce/screens/register_screen.dart';
import 'package:e_commerce/servises/auth.dart';
import 'package:e_commerce/widgets/custom_input_field.dart';
import 'package:flutter/material.dart';
import 'package:e_commerce/constants.dart';

class LoginScreen extends StatefulWidget 
static String routName = 'login';
const LoginScreen(Key? key) : super(key: key);

@override
State<LoginScreen> createState() => _LoginScreenState();


class _LoginScreenState extends State<LoginScreen> 
final GlobalKey<FormState> _key = GlobalKey<FormState>();
String? name;
String? password;
String? email;
@override
Widget build(BuildContext context) 
double height = MediaQuery.of(context).size.height;

return Scaffold(
  backgroundColor: kMainColor,
  body: SingleChildScrollView(
    child: Container(
      padding: const EdgeInsets.only(top: 100),
      alignment: Alignment.center,
      child: Column(
        children: [
          Image.asset("assets/images/icons/cart.png"),
          const Text('Buy now',
              style: TextStyle(
                  fontFamily: 'Corinthia',
                  color: Colors.black,
                  fontSize: 40,
                  fontWeight: FontWeight.bold)),
          SizedBox(
            height: height * 0.05,
          ),
          CustomTextField(
              onClick: (String value) 
                if (_key.currentState!.validate()) 
                  email = value;
                
              ,
              hint: 'Enter your email',
              icon: Icons.email_rounded),
          SizedBox(
            height: height * 0.02,
          ),
          CustomTextField(
              onClick: (String value) 
                if (_key.currentState!.validate()) 
                  password = value;
                
              ,
              hint: 'Enter your password',
              icon: Icons.lock),
          SizedBox(
            height: height * 0.05,
          ),
          MaterialButton(
            shape: const RoundedRectangleBorder(
                borderRadius: BorderRadius.all(Radius.circular(8))),
            color: Colors.black,
            onPressed: () 
              MyAuth().sinIn(email!, password!);
            ,
            child: const Text(
              'Login',
              style: TextStyle(fontSize: 20, color: Colors.white),
            ),
          ),
          SizedBox(
            height: height * 0.02,
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Text(
                'Don\'t have account?',
                style: TextStyle(fontSize: 20),
              ),
              TextButton(
                onPressed: () 
                  Navigator.of(context)
                      .pushReplacementNamed(Register.routName);
                ,
                child: const Text(
                  'Register  ',
                  style: TextStyle(fontSize: 20),
                ),
              )
            ],
            )
            ],
             ),
          ),
      ),
       // ),
     );
     
      

我使用了 Firebase 身份验证并创建了一个类来使用它我不知道它是否可能来自它的错误 我的身份验证是：

import 'package:firebase_auth/firebase_auth.dart';

 class MyAuth 
 final _auth = FirebaseAuth.instance;
 Future sinIn(String email, String password) async 
  final authResult = await _auth.signInWithEmailAndPassword(
    email: email, password: password);
   return authResult;
 

  Future register(String email, String password) async 
   final authResult = await _auth.createUserWithEmailAndPassword(
    email: email, password: password);
   return authResult;
    
    

完整的错误是：

════════ Exception caught by widgets library ═══════════════════════════════════
Closure call with mismatched arguments: function '_RegisterState.build.<anonymous closure>'
Receiver: Closure: (String) => Null
 Tried calling: _RegisterState.build.<anonymous closure>()
Found: _RegisterState.build.<anonymous closure>(String) => Null
The relevant error-causing widget was
CustomTextField
lib\screens\register_screen.dart:55

【参考方案1】：

看起来不匹配出现在 onClick 方法中，该方法在此处声明：

final Function? onClick; // it would help to further qualify Function here

你在这里调用它，不带参数：

    onSaved: onClick!(), // note no parameter

但是当你将它传递给构造函数时，你传入的是Function(String):

onClick: (String value) 

利用 Dart 的强类型来说明 onClick 是什么类型的函数。也许你的意思是：

final Function()? onClick;

或

final Function(String)? onClick;

另外，onSaved 我想你可能打算：

onSaved: () => onClick!(); // provide a function here that calls onClick