flex动态树(xml)

<?xml version="1.0" encoding="utf-8"?>
<mx:TitleWindow xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" showCloseButton="true" 
	title="动态树" close="close()" width="100%" height="100%" fontSize="12" fontFamily="Arial" 
	xmlns:ns1="com.eshangrao.controls.*" creationComplete="initApp()">
	
	<mx:Style source="css/popWin.css" />
	<mx:Script>	
		<![CDATA[
			import mx.events.TreeEvent;
			import com.adobe.serialization.json.*;
		    import mx.controls.Alert;
		   
		    [Bindable]
		    public var xml:XML;		    
		    public var selectedNode:XML;
		    
			private function close():void{
				//Alert.show("我要关闭了");
				this.parentApplication.closeWindow();
			}
			
			private function initApp():void{
				xml=new XML("<items label=\"root\"></items>");
				var node:XML=<item data="浙江" label="浙江" type="region"/>;
				xml.appendChild(node);
			}
			public function doFilter():ArrayCollection{
				Alert.show("我要过滤");
				return new ArrayCollection();
			}

			
			private function treeChange(event:Event):void{
				selectedNode=Tree(event.target).selectedItem as XML;
				if(selectedNode.hasSimpleContent()&&selectedNode.@type!="city"){
					var node:XML=<item data="杭州" label="杭州" type="city"/>;
				    selectedNode.appendChild(node);
				}				
			}
		]]>
	</mx:Script>
	
	<mx:VBox label="行政区县" width="100%" height="100%">
				<mx:Tree width="100%" height="99%" dataProvider="{xml}"
				   labelField="@label" change="treeChange(event)"></mx:Tree>
			</mx:VBox>
</mx:TitleWindow>