flex 实现横向树状图

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="absolute"
creationComplete="initApp()"
backgroundColor="#FFFFFF">
<mx:Canvas id="paper"
x="30"
y="24"
width="1200"
height="1800">
<mx:Canvas id="LEV"
name="LEV"
x="20"
y="17"
width="120"
height="120"
borderStyle="inset">
<mx:Button x="0"
y="74"
label="关键词导出"
width="116"
height="20"
color="#1B803A"/>
<mx:Text x="0"
y="20"
width="116"
height="55"
text="List PV:10000"
fontSize="12"
color="#C71B2B"/>
<mx:Image id="LEV_pic"
name="LEV_pic"
x="94"
y="44"
width="22"
height="22"
click="expandRootTree(event)">
<mx:source>{IMAGE_OPEN_SOURCE}</mx:source>
</mx:Image>
<mx:Button x="0"
y="94"
label="Button"
width="116"
height="20"
color="#128D1E"/>
<mx:Label x="0"
y="0"
text="Label"
width="116"
fontSize="14"
fontWeight="bold"
color="#362DF7"/>
</mx:Canvas>
</mx:Canvas>
<mx:Script>
<!--[CDATA[
import mx.controls.Label;
import mx.controls.Text;
import mx.controls.Button;
import mx.containers.Canvas;
impor