forked from lxm_flutter/FlutterUnit
113 lines
3.2 KiB
Dart
113 lines
3.2 KiB
Dart
import 'package:flutter/material.dart';
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/// create by 张风捷特烈 on 2020-03-31
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/// contact me by email 1981462002@qq.com
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/// 说明:
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// {
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// "widgetId": 198,
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// "name": 'Form基本使用',
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// "priority": 1,
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// "subtitle":
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// "【child】 : 子组件 【Widget】\n"
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// "【onChanged】 : 表单变化回调 【VoidCallback】\n"
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// "【onWillPop】 : 返回回调 【WillPopCallback】",
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// }
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class CustomForm extends StatefulWidget {
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const CustomForm({Key? key}) : super(key: key);
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@override
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_CustomFormState createState() => _CustomFormState();
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}
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class _CustomFormState extends State<CustomForm> {
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final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
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@override
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Widget build(BuildContext context) {
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return Form(
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onWillPop: () => _willPop(context),
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key: _formKey,
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onChanged: () {
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print('Form---onChanged');
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},
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child:
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Stack(
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alignment: Alignment.centerRight,
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children: <Widget>[
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SizedBox(
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width: 350,
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child: UnconstrainedBox(
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child: SizedBox(
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width: 200,
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height: 70,
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child: TextFormField(
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style: const TextStyle(textBaseline: TextBaseline.alphabetic),
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decoration: const InputDecoration(
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border: OutlineInputBorder(),
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labelText: 'username',
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),
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validator: _validateUsername,
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),
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),
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),
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),
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Positioned(
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top: 0, right: 0, child: _buildSubmitButton(context)),
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],
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),
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);
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}
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String? _validateUsername(value) {
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if (value.isEmpty) {
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return '用户名不能为空';
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}
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return null;
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}
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RaisedButton _buildSubmitButton(BuildContext context) {
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return RaisedButton(
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color: Colors.blue,
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shape: const CircleBorder(
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side: BorderSide(width: 2.0, color: Color(0xFFDFDFDF)),
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),
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onPressed: _onSubmit,
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child: const Icon(
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Icons.check,
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color: Colors.white,
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),
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);
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}
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void _onSubmit(){
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if(_formKey.currentState==null) return;
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if (_formKey.currentState!.validate()) {
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FocusScope.of(context).requestFocus(FocusNode());
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Navigator.of(context).pop();
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}
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}
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Future<bool> _willPop(context) async {
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return await showDialog(
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context: context,
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builder: (context) => AlertDialog(
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shape: const RoundedRectangleBorder(
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borderRadius: BorderRadius.all(Radius.circular(10))),
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title: const Text('提示'),
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content: const Text('你确定要离开此页吗?'),
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actions: <Widget>[
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FlatButton(
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onPressed: () => Navigator.of(context).pop(true),
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child: const Text('确定'),
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),
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FlatButton(
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onPressed: () => Navigator.of(context).pop(false),
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child: const Text('取消'),
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),
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],
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),
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) ??
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false;
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}
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}
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