动态增加tree组建节点

[Bindable]
   private var doc:XML=
    <folder label="我的文档" data="doc">
     <folder label="我的图片" data="pic"/>
     <folder label="我的音乐" data="music">
      <Pfolder label="PlaceNearBy.mp3"/>
      <Pfolder label="solo.mp3"/>
      <Pfolder label="流行乐" isBranch="true" data="pop"/>
     </folder>
     <folder label="我的应用程序" data="app"/>
     <folder label="我的视频" data="video"/>
    </folder>;
   [Bindable]
   private var docData:XMLListCollection=new XMLListCollection(doc.folder);
   private function test():void{
    Alert.show(docData.toXMLString());
   }
   private function addDoc():void{
    var newNode:XML=<Pfolder/>;
    newNode.@label=docName.text;
    var pFolder:XMLList=doc.folder.(@label=="我的音乐");
    pFolder[0].appendChild(newNode);
    docName.text="";
   }