Flex中DataGrid实现列（包括头部）中加入CheckBox全选功能 几种实现方法



在DataGrid中实现列中加入CheckBox这种用法很常见，项目中也经常会用到，在网上搜了下基本就是实现itemRender.但是 感觉网上提供的实现上好些地方都是多余的 经过自己的改造感觉还行 附上代码，同时希望大家举一反三 能实现添加其他组件到DataGrid列中

第一种方法：编写两个项选择器，继承CheckBox的方法，在DataGridview控件中的DataGridColumn列的属性headerRenderer，itemRenderer写入项选择器

CheckBoxHeaderRenderer.as

<pre class="java" name="code">package {import flash.events.Event;import flash.events.MouseEvent;import mx.collections.ArrayCollection;import mx.controls.Alert;import mx.controls.CheckBox;import mx.controls.DataGrid;import mx.events.DataGridEvent;public class CheckBoxHeaderRenderer extends CheckBox{private var sele:String;public function CheckBoxHeaderRenderer(){super();this.addEventListener(Event.CHANGE, clickHandlers);}override public function set data(value:Object):void{DataGrid(listData.owner).addEventListener                                    (DataGridEvent.HEADER_RELEASE,sortEventHandler);this.selected=this.sele=="true"?true:false;}private function sortEventHandler(event:DataGridEvent):void{if (event.itemRenderer == this)event.preventDefault();}protected function clickHandlers(event:Event):void{sele=(event.currentTarget.selected).toString();var a:ArrayCollection=DataGrid(listData.owner).dataProvider as ArrayCollection;for(var i:int=0;i<a.length;i++){(DataGrid(listData.owner).dataProvider as ArrayCollection)                                   .getItemAt(i).selected=(event.currentTarget.selected).toString();}(DataGrid(listData.owner).dataProvider as ArrayCollection).refresh();}}}  

CheckBoxItemDataRenderer.as

package {import flash.events.Event;import mx.collections.ArrayCollection;import mx.controls.CheckBox;import mx.controls.DataGrid;public class CheckBoxItemDataRenderer extends CheckBox{private var currentData:Object; //保存当前一行值的对象public function CheckBoxItemDataRenderer(){super();this.addEventListener(Event.CHANGE, changeHandler);}override public function set data(value:Object):void{this.currentData= value;this.selected = value.selected == "true"?true:false;}protected function changeHandler(event : Event) : void{currentData.selected = this.selected.toString();}/*override public function get data():Object{return currentData;}*/}}

DataGrid_Checkbox.mxml

<?xml version="1.0" encoding="utf-8"?><s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"    xmlns:s="library://ns.adobe.com/flex/spark"   xmlns:mx="library://ns.adobe.com/flex/mx"   xmlns:dataGrid="*"   minWidth="955" minHeight="600" creationComplete="getaa()"><fx:Script><![CDATA[import mx.collections.ArrayCollection;import mx.controls.Alert;[Bindable]private var data_myDataGrid:ArrayCollection=new ArrayCollection();private function headerClickHandler(event : Event) : void{/* for each(var obj: Object in data_myDataGrid){obj.selected = String(event.currentTarget.selected);}data_myDataGrid.refresh(); */}private function getaa():void{var obj:Object=new Object();obj.labe="1";obj.data="a";obj.selected="false";var obj2:Object=new Object();obj2.labe="2";obj2.data="b";obj2.selected="false";var obj3:Object=new Object();obj3.labe="3";obj3.data="c";obj3.selected="false";var obj4:Object=new Object();obj4.labe="4";obj4.data="a";obj4.selected="false";var obj5:Object=new Object();obj5.labe="5";obj5.data="b";obj5.selected="false";var obj6:Object=new Object();obj6.labe="6";obj6.data="c";obj6.selected="false";var obj7:Object=new Object();obj7.labe="7";obj7.data="a";obj7.selected="false";var obj8:Object=new Object();obj8.labe="8";obj8.data="b";obj8.selected="false";var obj9:Object=new Object();obj9.labe="9";obj9.data="c";obj9.selected="false";data_myDataGrid.addItem(obj);data_myDataGrid.addItem(obj3);data_myDataGrid.addItem(obj2);data_myDataGrid.addItem(obj4);data_myDataGrid.addItem(obj5);data_myDataGrid.addItem(obj6);data_myDataGrid.addItem(obj7);data_myDataGrid.addItem(obj8);data_myDataGrid.addItem(obj9);}protected function button1_clickHandler(event:MouseEvent):void{for(var i:int=0;i<data_myDataGrid.length;i++){if(data_myDataGrid.getItemAt(i).selected=='true'){Alert.show(data_myDataGrid.getItemAt(i).labe);}}}]]></fx:Script><mx:DataGrid dataProvider="{data_myDataGrid}" x="10" y="10"><mx:columns><mx:DataGridColumn dataField="labe" headerText="Label" /><mx:DataGridColumn dataField="data" headerText="Data" /><mx:DataGridColumndataField="selected" headerText="Select" itemRenderer="CheckBoxItemDataRenderer" headerRenderer="CheckBoxHeaderRenderer"  /></mx:columns></mx:DataGrid> <mx:Button click="button1_clickHandler(event)"/></s:Application>

第二种方法： 不继承checkBox类，直接在DataGrid中的DataGridColumn列中编写属性，项选择器，并写点击事件

用于存放数据的类，值得注意的是,selected属性用来存放复选框的状态.其他的是业务数据

package{[Bindable]//此类必须是可绑定的//用于存放数据public class DataObject{public var index:Number;public var selected:Boolean = false;//<span style="font-family: Helvetica, Tahoma, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);">存放复选框的状态</span>public var phone:String;public var name:String;}}

应用程序

<?xml version="1.0" encoding="utf-8"?><mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"layout="absolute"xmlns:ns1 ="com.common.*" creationComplete="application1_creationCompleteHandler(event)"><mx:Script><![CDATA[import mx.collections.ArrayCollection;import mx.controls.Alert;import mx.core.UIComponent;import mx.events.DragEvent;import mx.events.FlexEvent;import mx.events.ListEvent;[Bindable]public var obj:ArrayCollection;//用于存放datagrid中的所有数据,以及所有复选框的状态[Bindable]public var nums:String="";protected function application1_creationCompleteHandler(event:FlexEvent):void{// TODO Auto-generated method stubvar arr:ArrayCollection = new ArrayCollection();for(var i:Number=0;i<20;i++){var o:DataObject = new DataObject();o.selected=false;o.index = i;o.name = "test"+(i+1);o.phone = "10010-"+(i+1);arr.addItem(o);}setData(arr);}public function setData(arr:ArrayCollection):void{if(arr.length>0){this.obj=arr ;}}private function call():void{Alert.show(getSelectedObjects().toString());}private function getSelectedObjects():ArrayCollection{var selectedObjects:ArrayCollection=new ArrayCollection();if(obj.length>0){for(var i:Number=0;i<obj.length;i++){var o:DataObject = obj.getItemAt(i) as DataObject;if(o.selected){selectedObjects.addItem(o.phone);}}}return selectedObjects;}protected function checkbox2_changeHandler(event:Event):void{var slc:Boolean = selectAllCheckBox.selected;if(obj.length>0){for(var i:Number=0;i<obj.length;i++){obj.getItemAt(i).selected=slc;}}}protected function checkbox3_changeHandler(event:Event):void{if(obj.length>0){for(var i:Number=0;i<obj.length;i++){obj.getItemAt(i).selected=!obj.getItemAt(i).selected;}}}]]></mx:Script><mx:VBox><mx:DataGrid  id="dg"  width="100%" height="300"  dataProvider="{obj}"><mx:columns><mx:DataGridColumn width="16"><mx:itemRenderer><mx:Component><mx:CheckBox selected="{data.selected}" change="checkbox1_changeHandler(event)"><mx:Script><![CDATA[protected function checkbox1_changeHandler(event:Event):void{//将复选框的状态保存在obj中,防止出现复选框错乱的情况 outerDocument.obj.getItemAt(outerDocument.dg.selectedIndex).selected=event.target.selected; }]]></mx:Script></mx:CheckBox></mx:Component></mx:itemRenderer></mx:DataGridColumn><mx:DataGridColumn headerText="名称" dataField="name"/><mx:DataGridColumn headerText="电话" dataField="phone"/></mx:columns></mx:DataGrid><mx:HBox><mx:CheckBox label="全选" id="selectAllCheckBox" change="checkbox2_changeHandler(event)"/><mx:CheckBox label="反选" change="checkbox3_changeHandler(event)"/></mx:HBox><mx:Button label="呼叫" click="call()"/></mx:VBox></mx:Application>

运行即可。此方法，用全选和反选，不过全选和反选按钮是单独存在，不在Datagrid内

第三种方法

VO

package vos{    [Bindable]    public class TestVO    {        public function TestVO()        {        }                public var id:String;        public var label:String;        public var icon:String;                [Transient]        public var selected:Boolean = false;    }}

<?xml version="1.0" encoding="utf-8"?><s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"                xmlns:s="library://ns.adobe.com/flex/spark"                xmlns:mx="library://ns.adobe.com/flex/mx">        <s:layout>        <s:VerticalLayout paddingTop="5" paddingBottom="5" paddingLeft="5" paddingRight="5" gap="5"                           horizontalAlign="center" verticalAlign="middle"/>    </s:layout>            <fx:Script>        <![CDATA[            import mx.collections.ArrayCollection;            import mx.events.FlexEvent;                        import vos.TestVO;            [Bindable]            private var dp:ArrayCollection;                                    private function createData():void            {                dp = new ArrayCollection();                for (var i:int = 0; i < 10; i++)                 {                    var t:TestVO = new TestVO();                    t.id = String(i);                    t.label = "label" + i;                    t.icon = "assets/icons/" + i + ".png";                    t.selected = (Math.random() > .5) ? true : false;                                        dp.addItem(t);                }                            }                        private function deleteData():void            {                for (var i:int = dp.length - 1; i >= 0; i--)                 {                    var t:TestVO = dp.getItemAt(i) as TestVO;                    if(t.selected)                        dp.removeItemAt(i);                }                            }                        public function selectAll(event:MouseEvent):void            {                var cb:mx.controls.CheckBox = event.currentTarget as mx.controls.CheckBox;                                if(!dp)                {                    //还没数据的时候，你就别选中了，没用                    cb.selected = false;                    return;                }                                for each (var t:TestVO in dp)                 {                    t.selected = cb.selected;                }            }        >>    </fx:Script>        <fx:Declarations>        <!-- 将非可视元素（例如服务、值对象）放在此处 -->    </fx:Declarations>        <mx:DataGrid id="dg" width="400" height="300" dataProvider="{dp}">        <mx:columns>            <mx:DataGridColumn width="20" sortable="false">                <mx:headerRenderer>                    <fx:Component>                        <mx:CheckBox click="outerDocument.selectAll(event)"/>                    </fx:Component>                </mx:headerRenderer>                <mx:itemRenderer>                    <fx:Component>                        <mx:CheckBox selected="@{data.selected}"/>                    </fx:Component>                </mx:itemRenderer>            </mx:DataGridColumn>            <mx:DataGridColumn dataField="label"/>            <mx:DataGridColumn dataField="icon"/>a        </mx:columns>    </mx:DataGrid>    <s:HGroup>        <s:Button label="create data" click="createData()"/>        <s:Button label="delete selected data" click="deleteData()"/>    </s:HGroup></s:Application>

几个可能有疑问的地方： 

（1）selected="@{data.selected}"， "@"的作用是双向绑定，当data.selected改变时，checkbox的selected也随之改变，反之亦然。

（2）[Transient] 作用是指定接下来的字段在序列化的时候可以忽略。比如与后台交互的时候，后台vo不需要selected这个字段，加上它就行了（不加可能会导致警告）。

（3）例子里的CheckBox没有居中，如果要让它居中可以给它包上一个居中的容器。

用Hbox包一下就行了<mx:DataGridColumn width="20" sortable="false" textAlign="center">      <mx:headerRenderer>          <fx:Component>            <mx:HBox horizontalAlign="center" verticalAlign="middle">                <mx:CheckBox click="outerDocument.selectAll(event)"/>            </mx:HBox>        </fx:Component>      </mx:headerRenderer>      <mx:itemRenderer>        <fx:Component>            <mx:HBox horizontalAlign="center" verticalAlign="middle">                <mx:CheckBox selected="@{data.selected}"/>            </mx:HBox>        </fx:Component>      </mx:itemRenderer>  </mx:DataGridColumn>