flex按钮任意拖动

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" backgroundColor="#D99191">
<mx:Array id="coffeeArray">
</mx:Array>
<mx:Script>
  <![CDATA[
//    按钮控件任意拖动
    private function startMove(event:Event):void{
                Sprite(event.target).startDrag();  
            }     
            private function stopMove(event:Event):void{
                Sprite(event.target).stopDrag();  
            }  
    internal function InitLs():void
    {
      var srcArr:Array = new Array();
      srcArr.push("China Soft");
      srcArr.unshift("BOCO");
      srcArr.unshift("PCCW");
      SrcLs.dataProvider = srcArr;
      var desArr:Array = new Array("PM", "PL", "SE");
      DesLs.dataProvider=desArr;
      
      
    }
    
//    控件拖拽效果
    internal function MovLs():void
    {
      SrcLs.dragEnabled = true;
      SrcLs.dropEnabled = true;
      SrcLs.allowMultipleSelection = true;
      DesLs.dragEnabled = true;//
      DesLs.dropEnabled = true;
      var testDebStr:String = new String("Drag Success");
    }
  ]]>
</mx:Script>
  <mx:List x="111" y="92" height="282" id="SrcLs" width="200"></mx:List>
  <mx:List x="568" y="92" height="282" id="DesLs" width="200"></mx:List>
  <mx:Button x="334" y="123" label="初始化" width="167" click="InitLs()"/>
  <mx:Button x="334" y="193" label="拖拽效果" width="167" click="MovLs()"/>
  <mx:Button x="334" y="282" label="可以拖动" width="167" id="MLable" mouseDown="startMove(event)" mouseUp="stopMove(event)"/>
</mx:Application>