如何使用 email_validator 验证电子邮件地址
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【中文标题】如何使用 email_validator 验证电子邮件地址【英文标题】：How to use email_validator to validate an email address 【发布时间】：2022-01-14 05:15:34 【问题描述】：我正在尝试为我的应用程序构建一个注册页面。我尝试使用 email_validator 2.0.1 检查电子邮件是否有效，但它不起作用，它没有给出任何错误，也没有打印错误文本。
我的代码如下：
Widget buildSignInForm()
final _signInFormKey = GlobalKey<FormState>();
TextEditingController _emailController = TextEditingController();
TextEditingController _passwordController = TextEditingController();
return Padding(
padding: const EdgeInsets.all(20.0),
child: Form(
key: _signInFormKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
"Lütfen Giriş Yapınız",
style: TextStyle(fontSize: 25),
),
SizedBox(
height: 20,
),
TextFormField(
controller: _emailController,
validator: (value)
if (value != null && !EmailValidator.validate(value))
return "Please Enter a Valid E-mail";
else
return null;
,
【问题讨论】：
【参考方案1】：最快最简单的解决方案是使用正则表达式：
extension EmailValidator on String
bool isValidEmail()
return RegExp(
r'^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]1,3\.[0-9]1,3\.[0-9]1,3\.[0-9]1,3\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]2,))$')
.hasMatch(this);
并使用字符串的扩展名来验证电子邮件：
TextFormField(
autovalidate: true,
validator: (input) => input.isValidEmail() ? null : "Check your email",
)
Ref
【讨论】：
【参考方案2】：请参考以下代码
解决方案 1
class MainScreen extends StatefulWidget
MainScreen(Key key) : super(key: key);
@override
_MainScreenState createState() => _MainScreenState();
class _MainScreenState extends State<MainScreen>
final TextEditingController emailController = TextEditingController();
final FocusNode emailFocus = FocusNode();
final TextEditingController pswdController = TextEditingController();
final FocusNode pswdFocus = FocusNode();
final _validationKey = GlobalKey<FormState>();
@override
void initState()
super.initState();
@override
void dispose()
super.dispose();
int validateEmail(String emailAddress)
String patttern = r'^[\w-\.]+@([\w-]+\.)+[\w-]2,4$';
RegExp regExp = new RegExp(patttern);
if (emailAddress.isEmpty || emailAddress.length == 0)
return 1;
else if (!regExp.hasMatch(emailAddress))
return 2;
else
return 0;
int validatePassword(String pswd)
if (pswd.isEmpty || pswd.length == 0)
return 1;
else if (pswd != null && pswd.isNotEmpty && pswd.length <= 8)
return 2;
else
return 0;
@override
Widget build(BuildContext context)
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.lightBlue,
automaticallyImplyLeading: true,
leading: Icon(
Icons.arrow_back,
),
title: Text("Example"),
centerTitle: true,
),
body: Container(
padding: EdgeInsets.all(15.0),
child: Column(
children: [
Form(
key: _validationKey,
child: Column(
children: [
/* Email */
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
/* autovalidate is disabled */
controller: emailController,
keyboardType: TextInputType.emailAddress,
onChanged: (val) ,
maxLines: 1,
validator: (value)
int res = validateEmail(value);
if (res == 1)
return "Please fill email address";
else if (res == 2)
return "Please enter valid email address";
else
return null;
,
focusNode: emailFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Enter email address" ?? "",
),
),
SizedBox(
height: 15.0,
),
/* Password */
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
/* autovalidate is disabled */
controller: pswdController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.text,
maxLength: 160,
onChanged: (val) ,
obscureText: true,
maxLines: 1,
validator: (value)
int res = validatePassword(value);
if (res == 1)
return "Please enter password";
else if (res == 2)
return "Please enter minimum 9 characters";
else
return null;
,
focusNode: pswdFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Enter password" ?? "",
),
),
],
),
),
SizedBox(
height: 15.0,
),
OutlinedButton(
onPressed: ()
_validationKey.currentState.validate();
if (emailController.text.isEmpty)
emailFocus.requestFocus();
else if (pswdController.text.isEmpty ||
pswdController.text.length <= 8)
pswdFocus.requestFocus();
,
child: Text("Validate"),
)
],
),
),
);
解决方案 2
class HomeScreen extends StatelessWidget
HomeScreen(Key key) : super(key: key);
final _validationKey = GlobalKey<FormState>();
final TextEditingController emailAddressTextController =
TextEditingController();
bool isValidEmail = true;
bool isEmail(String string)
// Null or empty string is invalid
if (string == null || string.isEmpty)
return false;
const pattern = r'^[\w-\.]+@([\w-]+\.)+[\w-]2,4$';
final regExp = RegExp(pattern);
if (!regExp.hasMatch(string))
return false;
return true;
int validateEmailAddress(String emailAddress)
String patttern = r'^[\w-\.]+@([\w-]+\.)+[\w-]2,4$';
RegExp regExp = new RegExp(patttern);
if (emailAddress.isEmpty || emailAddress.length == 0)
return 1;
else if ((regExp.hasMatch(patttern)))
return 2;
else
return 0;
@override
Widget build(BuildContext context)
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.lightBlue,
automaticallyImplyLeading: true,
leading: Icon(
Icons.arrow_back,
),
title: Text("Example"),
centerTitle: true,
),
body: Container(
padding: EdgeInsets.all(15.0),
child: Column(
children: [
Form(
key: _validationKey,
child: Column(
children: [
TextFormField(
autovalidateMode: AutovalidateMode.always,
/* autovalidate is set to true */
controller: emailAddressTextController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.emailAddress,
maxLength: 160,
onChanged: (val)
isValidEmail = isEmail(val);
,
maxLines: 1,
validator: (value)
if (!isValidEmail)
return "Please enter valid email address";
else if (value.isEmpty)
return "please enter email address";
else
return null;
// int res = validateEmailAddress(value);
// if (res == 1)
// return "Please enter email address";
// else if (res == 2)
// return "Please enter valid email address";
// else
// return null;
//
,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Email Address" ?? "",
),
),
],
),
),
SizedBox(
height: 15.0,
),
],
),
),
);
【讨论】：
【参考方案3】：试试这个代码！
TextFormField(
controller: _emailController,
autovalidateMode: AutovalidateMode.onUserInteraction,
validator: (value)
if (value.isEmpty)
return 'Enter your Email address';
if (!RegExp(r'^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]1,3\.[0-9]1,3\.[0-9]1,3\.[0-9]1,3\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]2,))$').hasMatch(value))
return 'Enter a Valid Email address';
return null;
,)
然后点击注册按钮或注册按钮
if (formGlobalKey.currentState.validate())
// take action what you want
【讨论】：
【参考方案4】：我正在使用 form_field_validator
form_field_validator
import 'package:flutter/material.dart';
import 'package:form_field_validator/form_field_validator.dart';
void main()
runApp(MaterialApp(
debugShowCheckedModeBanner: false,
home: FormValidationExample(),
));
class FormValidationExample extends StatelessWidget with InputValidationMixin
final formGlobalKey = GlobalKey < FormState > ();
@override
Widget build(BuildContext context)
return Scaffold(
appBar: AppBar(
title: Text('Form validation example'),
),
body:
Padding(
padding: const EdgeInsets.symmetric(horizontal: 24),
child: Form(
key: formGlobalKey,
child: Column(
children: [
const SizedBox(height: 50),
TextFormField(
decoration: InputDecoration(
labelText: "Email"
),
validator: (email)
if (isEmailValid(email)) return null;
else
return 'Enter a valid email address';
,
),
const SizedBox(height: 24),
TextFormField(
decoration: InputDecoration(
labelText: "Password",
),
maxLength: 6,
obscureText: true,
validator: (password)
if (isPasswordValid(password)) return null;
else
return 'Enter a valid password';
,
),
const SizedBox(height: 50),
ElevatedButton(
onPressed: ()
if (formGlobalKey.currentState.validate())
formGlobalKey.currentState.save();
// use the email provided here
,
child: Text("Submit"))
],
),
),
));
mixin InputValidationMixin
bool isPasswordValid(String password) => password.length == 6;
bool isEmailValid(String email)
Pattern pattern =
r '^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]1,3\.[0-9]1,3\.[0-9]1,3\.[0-9]1,3\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]2,))$';
RegExp regex = new RegExp(pattern);
return regex.hasMatch(email);
【讨论】：
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