从头开发Flex树遇到的问题

   由于项目使用的applet书出现性能问题，现在老大要求重新开发一颗Flex树，而且还要求和之前的接口保持不变（入口数据格式、方法接口等）。因为Flex提供的数据描述器不能很好解析入口数据以及数还要支持CheckBox(级联、非级联)，所以我就重写了TreeDataDescriptor和TreeItemRenderer类。我按照TreeDataDescriptor提供的接口实现了相关方法，但在调试的的时候发现树一二级节点能够正确显示，点击二级节点时出现堆栈上溢异常，寻思了好久没能解决。还有一个问题就是点击二级节点时在TreeDataDescriptor的getChildren方法中node 的值为节点一级节点的值？
附上源代码：

[color=red]  tree.xml:[/color]
<treeNodes><treeNode><id>000000004000000000</id><name>全国</name><pID>-1</pID><nodeType>area</nodeType><imgURL>area.gif</imgURL><modifyDate>2010-10-18 14:59:04.0</modifyDate><checked>2</checked><temp>cn</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>010000004000000001</id><name>江苏_209</name><pID>000000004000000000</pID><nodeType>area</nodeType><imgURL>area.gif</imgURL><modifyDate>2010-10-19 09:48:49.0</modifyDate><checked>2</checked><temp>js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>010100004000000002</id><name>南京</name><pID>010000004000000001</pID><nodeType>area</nodeType><imgURL>area.gif</imgURL><modifyDate>2010-10-18 15:36:48.0</modifyDate><checked>2</checked><temp>nj.js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>01000120000008</id><name><![CDATA[yin]]></name><pID>010000004000000001</pID><nodeType>client</nodeType><imgURL>client.gif</imgURL><modifyDate>2010-10-19 11:10:05.0</modifyDate><checked>2</checked><temp>10.js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>01000120000005</id><name><![CDATA[client]]></name><pID>010000004000000001</pID><nodeType>client</nodeType><imgURL>client.gif</imgURL><modifyDate>2010-10-18 17:41:11.0</modifyDate><checked>2</checked><temp>mr.js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>01000120000004</id><name><![CDATA[|{}:"?></.,';[\]-=`~!@#$%^&*()_+]]></name><pID>010000004000000001</pID><nodeType>client</nodeType><imgURL>client.gif</imgURL><modifyDate>2010-10-18 15:17:37.0</modifyDate><checked>2</checked><temp>11.js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>01000120000002</id><name><![CDATA[aji]]></name><pID>010000004000000001</pID><nodeType>client</nodeType><imgURL>client.gif</imgURL><modifyDate>2010-10-18 15:04:07.0</modifyDate><checked>2</checked><temp>aji.js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>01000120000003</id><name><![CDATA[iqpl]]></name><pID>010000004000000001</pID><nodeType>client</nodeType><imgURL>client.gif</imgURL><modifyDate>2010-10-18 15:06:41.0</modifyDate><checked>2</checked><temp>iqpl.js</temp><state></state><isLeaf></isLeaf></treeNode><treeNode><id>01000120000001</id><name><![CDATA[|{}:"?></.,';[\]-=`~!@#$%^&*()_+]]></name><pID>010000004000000001</pID><nodeType>client</nodeType><imgURL>client.gif</imgURL><modifyDate>2010-10-19 10:34:01.0</modifyDate><checked>2</checked><temp>han.js</temp><state></state><isLeaf></isLeaf></treeNode></treeNodes>

[color=red]TreeDataDescriptor :[/color]
package com.smc.ascode
{
	import mx.collections.ICollectionView;
	import mx.collections.XMLListCollection;
	import mx.controls.treeClasses.DefaultDataDescriptor;

	public class TreeDataDescriptor extends DefaultDataDescriptor 
	{
		private var tree:Tree;
		public function TreeDataDescriptor(tree:Tree)
		{
			super();
			this.tree=tree;
		}

		public override function getChildren(node:Object, model:Object=null):ICollectionView
		{
			var xmlList:XMLListCollection=new XMLListCollection();
			if(node is XML)
			{
				var nodeXML:XML=XML(node);
				var tag:String=String(nodeXML.name()).toLowerCase();
				if("treenodes"==tag)
				{
					var childList:XMLList=nodeXML.elements("treeNode");
					var fnodeList:XMLListCollection=new XMLListCollection();
					for each(var o:XML in childList)
					{
						var parentID:String=o.pID;
						var id:String=o.id;
						if("-1"==parentID||!parentID)
						{
							 xmlList.removeAll();
							 xmlList.addItem(o);
							 break;
						}
						else
						{
							if(!SMCTreeUtil.nodeExsist(parentID,childList))
							{
								 xmlList.addItem(o);
							}
							else
							{
								var fNode:XML=SMCTreeUtil.getTopLeval(parentID,childList);
								if(!fNode){continue;}
								var fNodeId:String=fNode.id;
								var exist:Boolean=false;
								for each(var n:XML in xmlList)
								{
									if(fNodeId==n.id){exist=true;}
								}
								if(!exist)
								{ 
								   xmlList.addItem(o);
								}
							}
						}
					}
				}
				else if("treenode"==tag)
				{
				  	var nodeId:String=nodeXML.id;
				  	trace("getChildren \n");
				  	return	SMCTreeUtil.childs(nodeId,this.tree.xmlData);
				}
			}
			return xmlList;
		}
		
		public override function hasChildren(node:Object, model:Object=null):Boolean
		{
			var nodeXML:XML=XML(node);
			var tag:String=String(nodeXML.name()).toLowerCase();
			if("treenodes"==tag)
			{
				var nodeList:XMLList=nodeXML.elements("treeNode");
				if(0<nodeList.length())
				{
					return true;
				}
			}
			else
			{
				var id:String=nodeXML.id;
				trace("hasChildren \n");
				var childsList:XMLListCollection=SMCTreeUtil.childs(id,this.tree.xmlData);
				if(childsList&&0<childsList.length)
				{
					return true;
				}
				return true;
			}
			return false;
		}
		
		public override function isBranch(node:Object, model:Object=null):Boolean
		{
			if(node is XML)
			{
				var nodeXML:XML=XML(node);
				var tag:String=String(nodeXML.name()).toLowerCase();
				if(tag=="treenodes")
				{
					var nodeList:XMLList=nodeXML.elements("treeNode");
					if(0<nodeList.length())
					{
						return true;
					}
					return false;
				}
				else if(tag=="treenode")
				{
					var isLeafs:XMLList=nodeXML.elements("isLeaf");
					if(!isLeafs&&isLeafs.children())
					{
						var value:String=isLeafs.toString();
						trace("value:"+value);
						//获取isLeaf的值,如果值为xx的时候返回true/false
					}
					else
					{
						//根据node id查找是否有子节点,如果有则反true,如果没有则返回false
					}
				}
				
			}
			return true;
		}
		
		public override function getData(node:Object, model:Object=null):Object
		{
			return super.getData(node,model);
		}
		
		public override function addChildAt(parent:Object, newChild:Object, index:int, model:Object=null):Boolean
		{
			return super.addChildAt(parent,newChild,index,model);
		}
		
		public override function removeChildAt(parent:Object, child:Object, index:int, model:Object=null):Boolean
		{
			return super.removeChildAt(parent,child,index,model);
		}
	}
}

[color=red]TreeItemRenderer :[/color]
package com.smc.ascode
{
	import mx.controls.treeClasses.TreeItemRenderer;
    import mx.core.*;
	public class TreeItemRenderer extends mx.controls.treeClasses.TreeItemRenderer
	{
		public  static var res:Resource=new Resource();
		//是否有checkBox
        private var hasCheckBox:Boolean=false;	
        //节点类型
        private var nodeType:String;
        	
        /**
         *构造函数
         */ 
		public function TreeItemRenderer()
		{
			super();
		}
	}
}

附件为源码包，里面包数据及代码。程序要经过修改才可以运行。开发工具版本：Flex Bulider 3.0