Flex中List实现上移下移功能

我们在HTML中可以用JS实现Selecte框中内容的上移下移。昨天在项目中需要用Flex来实现这个功能。研究了一下 不难。

下面是具体实现代码：

<?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"    width="100%" height="100%"  ><fx:Style source="../../sps/sheet/css/forms.css"/><s:layout><s:VerticalLayout/></s:layout><fx:Declarations><!-- 将非可视元素（例如服务、值对象）放在此处 --></fx:Declarations><fx:Script><![CDATA[import mx.collections.ArrayCollection;import mx.utils.ObjectUtil;private var dp:ArrayCollection=new ArrayCollection([{Artist:'Pavement1', Album:'Slanted and Enchanted', Price:11.99, InStock: true},{Artist:'Pavement2', Album:'Crooked Rain, Crooked Rain', Price:10.99, InStock: false},{Artist:'Pavement3', Album:'Wowee Zowee', Price:12.99, InStock: true},{Artist:'Asphalt1', Album:'Brighten the Corners', Price:11.99, InStock: false},{Artist:'Asphalt2', Album:'Terror Twilight', Price:11.99, InStock: true},{Artist:'Asphalt3', Album:'Buildings Meet the Sky', Price:14.99, InStock: true},{Artist:'Other', Album:'Other', Price:5.99, InStock: true}]);private function up():void{if(list.selectedIndex>0){var i:int=list.selectedIndex;var tmp:Object=ObjectUtil.copy(list.selectedItem);var tmpupper:Object=dp.getItemAt(i-1);dp.setItemAt(tmpupper,i);dp.setItemAt(tmp,i-1);list.selectedIndex=i-1;list.selectedItem=tmp;}}private function down():void{if (list.selectedIndex<dp.length-1){var i:int=list.selectedIndex;var tmp:Object=ObjectUtil.copy(list.selectedItem);var tmplower:Object=dp.getItemAt(i+1);dp.setItemAt(tmplower,i);dp.setItemAt(tmp,i+1);list.selectedIndex=i+1;list.selectedItem=tmp;}}]]></fx:Script><s:Group width="100%" height="50%" id="a"></s:Group><s:Group><s:layout  ><s:VerticalLayout/></s:layout><mx:List dataProvider="{dp}" id="list" labelField="Artist"></mx:List><mx:Button label="UP" click="{up();}" enabled="{list.selectedItem!=null}"/><mx:Button label="DOWN" click="{down();}" enabled="{list.selectedItem!=null}"/></s:Group></s:Application>