参数不匹配的闭包调用:函数'_RegisterState.build.<匿名闭包>'接收者:闭包

Question

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

我认为我在这里创建的可重用Textform字段中的错误我的可重用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,
),
),
);
}
}

我在两个屏幕上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，我不知道这是否是错误我的身份验证等级是：

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
libscreensregister_screen.dart:55

Answer 1

看起来不匹配在onClick方法中，该方法在这里声明：

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

你在这里称之为，没有参数：

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

但是当您将它传递给构造函数时，您传递的是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;

此外，在onSaved中，我认为您可能有意：

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