Flex Tree自动定位节点

说明：根据comboBox控件中的选择内容，自动定位到Tree中的节点，并展开
http://luhantu.iteye.com/blog/1536277

<?xml version="1.0" encoding="utf-8"?>
<s:VGroup xmlns:fx="http://ns.adobe.com/mxml/2009" 
		  xmlns:s="library://ns.adobe.com/flex/spark" 
		  xmlns:mx="library://ns.adobe.com/flex/mx" width="100%" height="100%">
	<fx:Declarations>
		<fx:XMLList id="treeData">
			<node label="Mail Box">
				<node label="Inbox">
					<node label="Marketing"/>
					<node label="Product Management"/>
					<node label="Personal"/>
				</node>
				<node label="Outbox">
					<node label="Professional"/>
					<node label="Personal"/>
				</node>
				<node label="Spam"/>
				<node label="Sent"/>
			</node>
		</fx:XMLList>
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			 import mx.events.ListEvent;
			private function comboBox_change(evt:ListEvent):void 
			{
				var team:String = ComboBox(evt.currentTarget).selectedItem.@label;
				var node:XMLList = treeData.node.node.(@label == team);
				expandParents(node[0]);
				tree.selectedItem = node[0];
				var idx:int = tree.getItemIndex(node[0]);
				tree.scrollToIndex(idx);
			}
			
			private function expandParents(node:XML):void 
			{
				if (node && !tree.isItemOpen(node)) {
					tree.expandItem(node,true);
					expandParents(node.parent());
				}
			}
		]]>
	</fx:Script>
	<mx:ComboBox id="comboBox"
				 prompt="Please select a team..."
				 dataProvider="{treeData.node.node}"
				 labelField="@label"
				 change="comboBox_change(event);"/>
	<mx:Tree id="tree"
			 dataProvider="{treeData}"
			 labelField="@label"
			 showRoot="false"
			 width="300"
			 rowCount="8" />
</s:VGroup>