向Tree空间添加删除XML数据节点_Flex4

Flex4控件例程： 基于HttpService的运用向Tree空间中添加和删除XML数据格式的节点操作

<?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" minWidth="955" minHeight="600">
	<s:layout>
		<s:VerticalLayout verticalAlign="middle" horizontalAlign="center"/>
	</s:layout>
	<fx:Script>
		<![CDATA[
			import mx.controls.Alert;
			import mx.events.FlexEvent;
			import mx.rpc.events.ResultEvent;
			
						protected function http_resultHandler(event:ResultEvent):void
			{
				var result:XML = event.result as XML ;
				tree.dataProvider = result ;
				trace(result) ;
			}


			protected function addNode():void
			{
				// TODO Auto-generated method stub
				var xml:XML = tree.selectedItem as XML ;
				if(xml.length()>0){
					var newNode:XML = <node /> ;
					newNode.@value=addItem.text ;
					xml.appendChild(newNode) ;
				}
				addItem.text = "" ;
				
			}
			protected function delNode():void
			{
				if(!tree.selectedItem.hasOwnProperty("CD")){
					tree.dataDescriptor.removeChildAt(tree.selectedItem.parent(),tree.selectedItem,tree.selectedItem.childIndex(),tree.dataProvider);
				}else{
					Alert.show("不能删除根节点","系统提示");
				}

			}

		]]>
	</fx:Script>
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
		<!--<fx:XML source="data/cd.xml" format="e4x" id="data"/>-->
		<s:HTTPService id="http" url="data/cd.xml" resultFormat="e4x" result="http_resultHandler(event)"/>
	</fx:Declarations>
	<mx:Tree id="tree" labelField="@value" width="300" height="400"></mx:Tree>
	<s:Group width="304" height="27">
		<s:TextInput id ="addItem" x="0" y="5" height="100%" width="100"/>
		<s:Button x="118" y="2" label="增加节点" enabled="{addItem.text!=''?true:false}" click="addNode()"/>
		<s:Button x="224" y="2" label="删除节点"  enabled="{tree.selectedIndex==-1?false:true}" click="delNode()"/>
	</s:Group>
</s:Application>

XML文件：
cd.xml

<?xml version="1.0" encoding="ISO-8859-1" ?> 
<!--  Edited with XML Spy v2007 (http://www.altova.com) 
  --> 
<CDS value="Root">
	<CD value="CD1">
	  <TITLE value="TITLE">Empire Burlesque</TITLE> 
	  <ARTIST value="ARTIST">Bob Dylan</ARTIST> 
	  <COUNTRY value="COUNTRY">USA</COUNTRY> 
	  <COMPANY value="COMPANY">Columbia</COMPANY> 
	  <PRICE value="PRICE">10.90</PRICE> 
	  <YEAR value="YEAR">1985</YEAR> 
	</CD>
	<CD value="CD2">
	  <TITLE value="TITLE">Hide your heart</TITLE> 
	  <ARTIST value="ARTIST">Bonnie Tyler</ARTIST> 
	  <COUNTRY value="COUNTRY">UK</COUNTRY> 
	  <COMPANY value="COMPANY">CBS Records</COMPANY> 
	  <PRICE value="PRICE">9.90</PRICE> 
	  <YEAR value="YEAR">1988</YEAR> 
	</CD>
	<CD value="CD3">
	  <TITLE value="TITLE">Greatest Hits</TITLE> 
	  <ARTIST value="ARTIST">Dolly Parton</ARTIST> 
	  <COUNTRY value="COUNTRY">USA</COUNTRY> 
	  <COMPANY value="COMPANY">RCA</COMPANY> 
	  <PRICE value="PRICE">9.90</PRICE> 
	  <YEAR value="YEAR">1982</YEAR> 
	  </CD>
	<CD value="CD4">
	  <TITLE value="TITLE">Still got the blues</TITLE> 
	  <ARTIST value="ARTIST">Gary Moore</ARTIST> 
	  <COUNTRY value="COUNTRY">UK</COUNTRY> 
	  <COMPANY value="COMPANY">Virgin records</COMPANY> 
	  <PRICE value="PRICE">10.20</PRICE> 
	  <YEAR value="YEAR">1990</YEAR> 
	</CD>
	<CD value="CD5">
	  <TITLE value="TITLE">Eros</TITLE> 
	  <ARTIST value="ARTIST">Eros Ramazzotti</ARTIST> 
	  <COUNTRY value="COUNTRY">EU</COUNTRY> 
	  <COMPANY value="COMPANY">BMG</COMPANY> 
	  <PRICE value="PRICE">9.90</PRICE> 
	  <YEAR value="YEAR">1997</YEAR> 
	</CD>
	<CD value="CD6">
	  <TITLE value="TITLE">One night only</TITLE> 
	  <ARTIST value="ARTIST">Bee Gees</ARTIST> 
	  <COUNTRY value="COUNTRY">UK</COUNTRY> 
	  <COMPANY value="COMPANY">Polydor</COMPANY> 
	  <PRICE value="PRICE">10.90</PRICE> 
	  <YEAR value="YEAR">1998</YEAR> 
	</CD>
</CDS>