The TextFormField has a validator method which is called to validate the input. The validator method returns a string containing the error message when the user input is invalid or null if the user input is valid.In most cases, you will use a regular expression to check the input. We ...
this.validator, // 初始值 this.initialValue, // 是否自动校验。 this.autovalidate=false, this.enabled=true, }) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 3. TextFormField 为了方便使用,Flutter 提供了一个 TextFormField ,它继承自 FormField 类,也是 TextField 的一个包装类,所以...
在_MyFormState类中,我们定义了表单的布局和行为: class _MyFormState extends State<MyForm> { final _formKey = GlobalKey<FormState>(); @override Widget build(BuildContext context) { return Form( key: _formKey, child: Column( children: <Widget>[ TextFormField( validator: (value) { if...
百度试题 结果1 题目在Flutter中,如何处理表单验证? A. Form B. TextFormField C. Validator D. FormField 相关知识点: 试题来源: 解析 A 反馈 收藏
阅读原理之前可以先移步到:flutter 表单Form使用示例,大致了解下Form怎么使用。 实现原理分析 从上面例子可知,主要用到Form+TextFormField,那么我们就从Form+TextFormField入手来分析。 Form+TextFormField结构上的关系 代码我做了精简版,主要为了突出结构,如下: ...
import'package:flutter/material.dart';import'package:validate/validate.dart';voidmain() => runApp(newMaterialApp( title:'Forms in Flutter', home:newLoginForm(), theme: ThemeData.dark(), ));classLoginFormextendsStatefulWidget{Stringemail;Stringpassword;finalFunctionsaveEmail;finalFunctionsavePassword;fi...
style: const TextStyle(fontSize: 18,color:Colors.blue),//it should be added in theme controller: controller.firstName, decoration: const InputDecoration( hintText: 'First Name', prefixIcon: Icon(Icons.person), ), validator: (text)=>MyValidator.validateEmtpyText('FirstName', text), ...
刚开始做Flutter文本框时候,使用的是TextField。似乎大多数情况下都没有问题。...但是现在有一种情况: **问题1: **当页面文本框中的初始值是动态的,从后台获取到的时候,应该怎么办呢?这种情况下,说明创建TextEditingController时,并不知道文本内容。...所以我去找了
FormBuilderField( name: "name", validator: FormBuilderValidators.compose([ # Flutter Form Builder FormBuilderValidators.required(), ]), builder: (FormFieldState<dynamic> field) { return InputDecorator( decoration: InputDecoration( labelText: "Select option", contentPadding: EdgeInsets.only(top: 10...
validator:(String?value)=>value==null||value.trim().isEmpty?'This field is required':null, ),FilledButton( child:constText('Submit'), onPressed:() {print('valid: ${key.currentState!.validate()}'); }, ), ], ), ); } }