forked from lxm_flutter/FlutterUnit
69 lines
2.1 KiB
Dart
69 lines
2.1 KiB
Dart
import 'package:flutter/material.dart';
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/// create by 张风捷特烈 on 2020/9/21
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/// contact me by email 1981462002@qq.com
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/// 说明: 223 DropdownButtonFormField 表单下拉框
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/// 底层依赖 DropdownButton 实现，所以基本属性类似。但拥有 FormField 的特性，可以回调 onSaved、validator 方法。
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/// link: 55,222
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///
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// {
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// "widgetId": 223,
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// "name": '表单下拉框简单使用',
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// "priority": 1,
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// "subtitle":
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// "【items】 : 子组件列表 【List<DropdownMenuItem<T>>】\n"
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// "【validator】 : 表单验证回调 【FormFieldValidator<T>】\n"
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// "【onSaved】 : 表单保存回调 【FormFieldSetter<T>】\n"
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// "其他属性详见 DropdownButton，表单校验特性详见 FormField。",
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// }
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class DropdownButtonFormFieldDemo extends StatefulWidget {
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@override
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_DropdownButtonFormFieldDemoState createState() => _DropdownButtonFormFieldDemoState();
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}
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class _DropdownButtonFormFieldDemoState extends State<DropdownButtonFormFieldDemo> {
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Color _color;
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final _colors = [Colors.red, Colors.yellow, Colors.blue, Colors.green];
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final _info = ["红色", "黄色", "蓝色", "绿色"];
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@override
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Widget build(BuildContext context) {
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return Wrap(
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children: <Widget>[
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Container(
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margin: EdgeInsets.symmetric(horizontal: 20),
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width: 50,
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height: 50,
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color: _color??_colors[0],
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),
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SizedBox(
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width: 80,
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child: DropdownButtonFormField<Color>(
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value: _color,
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elevation: 1,
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hint: Text('选择颜色',style: TextStyle(fontSize: 12),),
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icon: Icon(
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Icons.expand_more,
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size: 20,
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color: _color,
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),
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items: _buildItems(),
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onChanged: (v) => setState(() => _color = v)
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),
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)
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],
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);
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}
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List<DropdownMenuItem<Color>> _buildItems() => _colors
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.map((e) => DropdownMenuItem<Color>(
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value: e,
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child: Text(
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_info[_colors.indexOf(e)],
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style: TextStyle(color: e),
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)))
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.toList();
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} |