Flutter系列教程之(8)——CheckBox多选框及动态更改多选框

目录

1.星级组件使用

2.多选框使用及数据更改

3.完整源码

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最近项目需求需要调整页面,记录一下实现过程

这次主要是要实现个评价页面,选择不同的星级显示不同的多选框数据,加上之前也没有使用过CheckBox,今天便是一起讲吧

1.星级组件使用

首先,我们有使用到星级评分组件 在pubspec.yaml文件中添加下面依赖

flutter_simple_rating_bar: ^0.0.3

使用的话页面也是有个例子介绍,我们直接拿来即可使用

RatingBar( //默认选择5星 rating: 5, //总星星数目 starCount: 5, //星星图标 icon: Icon( Icons.star, size: 40, color: Colors.grey, ), spacing: 5.0, size: 40, isIndicator: false, //是否可选半星 allowHalfRating: true, onRatingCallback:(double value, ValueNotifier<bool> isIndicator) { //value是点击后选中的星星数(即评分),范围为1-rating(我们上面rating为5) }, color: Colors.amber, )

现在我们要根据选择⭐的数目不同,从而显示不同的文字,这过程是动态的,所以我们选择使用StatefulWidget作为页面继承的基类

我们先在State类中加上相应的数据,如下所示

//显示的文字信息 List typeList = ["非常不满意", "不满意", "基本满意", "满意", "非常满意"]; //当前选择type的下标 int selectType = 4;

我们文字显示内容是typeList[selectType],我们在星级评分选择的回调函数,更改selecType即可实现更改UI的功能

Column( children: [ RatingBar( rating: 5, //默认选择5星 starCount: 5, //总星星数目 //星星图标 icon: Icon( Icons.star, size: 40, color: Colors.grey, ), spacing: 5.0, size: 40, isIndicator: false, //是否可选半星 allowHalfRating: true, onRatingCallback: (double value, ValueNotifier<bool> isIndicator) { //更改数据同时也要更改UI,所以使用setState方法 setState(() { //注意 星级从1开始,selectType是下标,从0开始,需要减1 selectType = value.toInt() - 1; }); }, color: Colors.amber, ), //取指定下标的文字内容展示 Text(typeList[selectType]) ], ) 2.多选框使用及数据更改

CheckBox多选框的使用需要定义一个bool类型的数据,每次点击需要更改此数据来改变CheckBox的选择状态

由于我们是使用的列表数据，所以每个数据写个变量不太现实,而且繁琐,所以可以考虑在实体类中加个bool类型的字段,用来存储CheckBox选择的状态

这里,数据我就暂且写死,实际上是要通过调用接口获取的

void initTagData() { var data = """{ "code":200, "error":"", "ReturnValue":[{"generalstars":"1","tagid":"109759610348409856","tagname":"无理由超过法定办理时间","updatetime":"2020-06-12 17:38:00"},{"generalstars":"1","tagid":"6176177900787350","tagname":"在办事指南之外增加新的审批条件","updatetime":"2020-08-27 00:00:00"},{"generalstars":"1","tagid":"6176177900787351","tagname":"需提供办事指南之外的申报材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"1","tagid":"7176177890787535","tagname":"无理由超过法定办理时间","updatetime":"2020-08-27 00:00:00"},{"generalstars":"2","tagid":"6176177900787349","tagname":"未在承诺时间内办结","updatetime":"2020-08-27 00:00:00"},{"generalstars":"2","tagid":"6176177900787347","tagname":"没有提供材料样本","updatetime":"2020-08-27 00:00:00"},{"generalstars":"2","tagid":"6176177900787348","tagname":"没有提供材料清单","updatetime":"2020-08-27 00:00:00"},{"generalstars":"3","tagid":"119596473292723200","tagname":"22222","updatetime":"2020-06-12 17:38:00"},{"generalstars":"3","tagid":"6176177900787346","tagname":"在承诺的时间内办结","updatetime":"2020-08-27 00:00:00"},{"generalstars":"3","tagid":"6176177900787345","tagname":"提供申报材料样本","updatetime":"2020-08-27 00:00:00"},{"generalstars":"3","tagid":"6176177900787344","tagname":"一次性告知需要补正的材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"4","tagid":"6176177900787340","tagname":"填写一张表单就可以完成申报","updatetime":"2020-08-27 00:00:00"},{"generalstars":"4","tagid":"6176177900787341","tagname":"在线提交材料窗口核验","updatetime":"2020-08-27 00:00:00"},{"generalstars":"4","tagid":"6176177900787342","tagname":"一张清单告知全部申报材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"5","tagid":"7176177890787335","tagname":"一窗受理一次办结","updatetime":"2020-08-27 00:00:00"},{"generalstars":"5","tagid":"7176177890787235","tagname":"可以先受理后补材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"5","tagid":"7176177890787435","tagname":"不用提交证明","updatetime":"2020-08-27 00:00:00"}] }"""; Map<String, dynamic> responseData = jsonDecode(data); var tagListModel = TagListModel.fromJson(responseData); if (tagListModel.code == 200) { //注意要使用setState,才会使UI发生变化(因为网络请求是耗时任务,可能界面渲染完毕后才能请求到数据) setState(() { tagList.addAll(tagListModel.tagItems); }); } }

TagListModel是生成的实体类,生成的步骤已经在上篇文章讲解到,这里就不在赘述了

按照上面说的思路,我们在TagListModel的实体类中**(其实是在TagItem中)**,添加一个bool类型的字段,用来作为存储CheckBox选择的状态,

这里使用插件生成的实体类(TagListModel里面还包含有个实体类),原本应该是ReturnValue,但为了方便,我将其改了个名字TagItem

Flutter中的CheckBox是只有一个框,并不包含文字,所以我们得组合一个文本,拼成一个Widget,_tagView()这个方法就是每个选项

Widget _tagView(item) { var str = item.tagname; return InkWell( child: Row( children: <Widget>[ Checkbox( value: item.flag, activeColor: Colors.blue, onChanged: (bool val) { // val 是布尔值 this.setState(() { item.flag = val; }); }, ), Text(str), ], ), onTap: () { setState(() { item.flag = !item.flag; }); }, );

这里最外层使用了InkWell,是因为其有onTag的点击事件方法 点击整行都可以去改变CheckBox的状态,用户体验比较友好,如果没有的话,只能点击CheckBox的框来改变状态

有了上面的一个子项,现在我们需要构建一个多选选项列表(列表包含N个_tagView组件)

先声明两个数组,用来存放数据

//标签数据(存放所有数据) List<TagItem> tagList = []; //临时存放的数据,后面评价提交需要 List<TagItem> tempTagList = [];

这里为什么需要两个数组呢?

主要是考虑到后面需要获取勾选的数据,所以才考虑再多加一个临时的列表

每次改变星级的时候,列表选项的数据就会改变,之后我们只需要去这个临时列表中筛选状态为true的数据即可

List<Widget> _tagList() { List<Widget> widgetList = []; var list = this.tagList; tempTagList.clear(); var star = selectType.toInt() + 1; //匹配相同星级数据 for (var i = 0; i < list.length; i++) { var item = list[i]; if (item.generalstars == star.toString()) { //存在临时表中,之后可以快速查找用户的选择 tempTagList.add(item); var row = _tagView(item); widgetList.add(row); } } return widgetList; }

由于数据较少,可以使用Column用来包裹上面的组件_tagList

//标签选项 Container( decoration: BoxDecoration(color: Colors.white), padding: EdgeInsets.fromLTRB(10, 0, 15, 5), child: Column( children: _tagList(), ) )

由于提交标签需要传标签的id,而且需要逗号隔开,所以需要遍历临时选项列表,处理一下即可

3.完整源码 //处理标签 var tagId = ""; for (var i = 0; i < tempTagList.length; i++) { var item = tempTagList[i]; //查找选择的标签数据 if (item.flag) { tagId += item.tagid + ","; } } if (tagId.length>0) { tagId = tagId.substring(0, tagId.length - 1); } print(tagId); import 'dart:convert'; import 'package:flutter/material.dart'; import 'package:flutter_demo/model/tag_list_model.dart'; import 'package:flutter_simple_rating_bar/flutter_simple_rating_bar.dart'; class CheckBoxPage extends StatefulWidget { @override State<StatefulWidget> createState() { return new CheckBoxState(); } } class CheckBoxState extends State<CheckBoxPage> { //标签数据 List<TagItem> tagList = []; //临时标签,后面评价提交需要 List<TagItem> tempTagList = []; List typeList = ["非常不满意", "不满意", "基本满意", "满意", "非常满意"]; //当前选择type的下标 int selectType = 4; @override void initState() { //初始化数据(这里是暂时写死,实际中这里是调用接口) initTagData(); } void initTagData() { var data = """{ "code":200, "error":"", "ReturnValue":[{"generalstars":"1","tagid":"109759610348409856","tagname":"无理由超过法定办理时间","updatetime":"2020-06-12 17:38:00"},{"generalstars":"1","tagid":"6176177900787350","tagname":"在办事指南之外增加新的审批条件","updatetime":"2020-08-27 00:00:00"},{"generalstars":"1","tagid":"6176177900787351","tagname":"需提供办事指南之外的申报材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"1","tagid":"7176177890787535","tagname":"无理由超过法定办理时间","updatetime":"2020-08-27 00:00:00"},{"generalstars":"2","tagid":"6176177900787349","tagname":"未在承诺时间内办结","updatetime":"2020-08-27 00:00:00"},{"generalstars":"2","tagid":"6176177900787347","tagname":"没有提供材料样本","updatetime":"2020-08-27 00:00:00"},{"generalstars":"2","tagid":"6176177900787348","tagname":"没有提供材料清单","updatetime":"2020-08-27 00:00:00"},{"generalstars":"3","tagid":"119596473292723200","tagname":"22222","updatetime":"2020-06-12 17:38:00"},{"generalstars":"3","tagid":"6176177900787346","tagname":"在承诺的时间内办结","updatetime":"2020-08-27 00:00:00"},{"generalstars":"3","tagid":"6176177900787345","tagname":"提供申报材料样本","updatetime":"2020-08-27 00:00:00"},{"generalstars":"3","tagid":"6176177900787344","tagname":"一次性告知需要补正的材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"4","tagid":"6176177900787340","tagname":"填写一张表单就可以完成申报","updatetime":"2020-08-27 00:00:00"},{"generalstars":"4","tagid":"6176177900787341","tagname":"在线提交材料窗口核验","updatetime":"2020-08-27 00:00:00"},{"generalstars":"4","tagid":"6176177900787342","tagname":"一张清单告知全部申报材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"5","tagid":"7176177890787335","tagname":"一窗受理一次办结","updatetime":"2020-08-27 00:00:00"},{"generalstars":"5","tagid":"7176177890787235","tagname":"可以先受理后补材料","updatetime":"2020-08-27 00:00:00"},{"generalstars":"5","tagid":"7176177890787435","tagname":"不用提交证明","updatetime":"2020-08-27 00:00:00"}] }"""; Map<String, dynamic> responseData = jsonDecode(data); var tagListModel = TagListModel.fromJson(responseData); if (tagListModel.code == 200) { //注意要使用setState,才会使UI发生变化(因为网络请求是耗时任务,可能界面渲染完毕后才能请求到数据) setState(() { tagList.addAll(tagListModel.tagItems); }); } } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text("评价"), ), body: Column( children: [ Container( decoration: BoxDecoration(color: Colors.white), padding: EdgeInsets.fromLTRB(15, 0, 15, 10), child: Wrap( spacing: 10, children: [ Center( child: Column( children: [ RatingBar( rating: 5, //默认选择5星 starCount: 5, //总星星数目 //星星图标 icon: Icon( Icons.star, size: 40, color: Colors.grey, ), spacing: 5.0, size: 40, isIndicator: false, //是否可选半星 allowHalfRating: true, onRatingCallback: (double value, ValueNotifier<bool> isIndicator) { //更改数据同时也要更改UI,所以使用setState方法 setState(() { //注意 星级从1开始,selectType是下标,从0开始,需要减1 selectType = value.toInt() - 1; }); }, color: Colors.amber, ), _tipText() ], ), ) ], ), ), //标签选项 Container( decoration: BoxDecoration(color: Colors.white), padding: EdgeInsets.fromLTRB(10, 0, 15, 5), child: Column( children: _tagList(), )), Container( decoration: BoxDecoration(color: Colors.white), padding: EdgeInsets.fromLTRB(10, 0, 15, 5), child: FlatButton( child: Text("提交"), onPressed: () { //处理标签 var tagId = ""; for (var i = 0; i < tempTagList.length; i++) { var item = tempTagList[i]; //查找选择的标签数据 if (item.flag) { tagId += item.tagid + ","; } } if (tagId.length>0) { tagId = tagId.substring(0, tagId.length - 1); } print(tagId); }, )), ], ), ); } Widget _tipText() { //根据selectType变更UI return Text(typeList[selectType]); } List<Widget> _tagList() { List<Widget> widgetList = []; var list = this.tagList; tempTagList.clear(); var star = selectType.toInt() + 1; for (var i = 0; i < list.length; i++) { var item = list[i]; if (item.generalstars == star.toString()) { //存在临时表中,之后可以快速查找用户的选择 tempTagList.add(item); var row = _tagView(item); widgetList.add(row); } } return widgetList; } Widget _tagView(item) { var str = item.tagname; return InkWell( child: Row( children: <Widget>[ Checkbox( value: item.flag, activeColor: Colors.blue, onChanged: (bool val) { // val 是布尔值 this.setState(() { item.flag = val; }); }, ), Text(str), ], ), onTap: () { setState(() { item.flag = !item.flag; }); }, ); } }