HSlider的标签随滑动动态显示

HSlider的labels属性设置后，会自动显示label在相应的刻度范围。比如labels=[2000,2020],则在滑动条的左右两端分别显示2000,2020.现在需要在滑动的时候，让slider的值动态的显示出来，研究了半天自带的属性，无法实现，所以使用label和slider结合的方式来做。如下代码直接运行即可看到效果。
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" >
<mx:Script>
        <![CDATA[
        import mx.controls.Text;
        import mx.events.SliderEvent;
            private var thumbIdx:int; 
            private var labelv:String;
           private function setThumbIdx(evt:SliderEvent):void {
                switch (evt.type) {
                    case SliderEvent.THUMB_RELEASE:
                       thumbIdx = evt.thumbIndex;
                        var scale:int=dataSlider.width/(dataSlider.maximum-dataSlider.minimum);
                        if(thumbIdx==0)
                        {
                        htipminvalue.text=labelv;
                            htipminvalue.x=dataSlider.x+((Number(labelv))%dataSlider.minimum)*scale;
                        }
                         if(thumbIdx==1)
                        {
                        htipmaxvalue.text=labelv;
                            htipmaxvalue.x=dataSlider.x+((Number(labelv))%dataSlider.minimum)*scale;
                        }
                        break;

                }
           }
           private function formatFunction(item:Object):String {
                labelv=item.toString();
                 return item.toString();
           }
        ]]>
    </mx:Script>

    <mx:Canvas  label="ComboBox Control Example" 
        height="75%" width="75%"
        paddingTop="10" paddingBottom="10" paddingLeft="10" paddingRight="10"
        color="0xffffff" >
        <mx:Label id="htipminvalue" y="40" text="2000" x="50"/>
        <mx:Label id="htipmaxvalue" y="40"  text="2020" x="250"/>
        <mx:HSlider id="dataSlider" y="50"    width="200"  x="50" allowTrackClick="false"
minimum="2000" maximum="2020" values="[2000,2020]" showDataTip="true" snapInterval="5" 
dataTipFormatFunction="formatFunction" liveDragging="true"       
  thumbRelease="setThumbIdx(event);"
thumbCount="2" allowThumbOverlap="false" tickInterval="5" showTrackHighlight="true"
/>
   </mx:Canvas>
</mx:Application>