flex 定时器

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"
               creationComplete="init()"
               minWidth="955" minHeight="600">
    <mx:Script>
        <![CDATA[
            import mx.events.FlexEvent;
            
            [Bindable]
            public var str:String;
            public var timer:Timer;
            
            protected function init():void
            {
                // TODO Auto-generated method stub
                timer = new Timer(1000);
        
                timer.addEventListener(TimerEvent.TIMER,timehandle);
                timer.start();
            }
            
            private function timehandle(e:TimerEvent):void
            {
                var count:int = timer.currentCount;
                str = timeTransform(66,count);
            }
            /* private function timeTransfo(count:int):String
            {
                var str:String = "";
                var hour:int = Math.floor(count/3600);
                var miniter:int = count%3600/60;
                var second:int = count%60;
                str = hour+"时"+miniter+"分"+second+"秒";
                return str;
            } */
            
            private function timeTransform(stattime:int,counter:int):String
            {
                var str:String = "";
                var count:int = stattime - counter;
                var hour:int = Math.floor(count/3600);
                var miniter:int = count%3600/60;
                var second:int = count%60;
                str = hour+"时"+miniter+"分"+second+"秒";
                if(second==0 && hour==0 && miniter==0)timer.stop();
                return str;
            }
        ]]>
    </mx:Script>
    <mx:Label x="194" y="241" width="311" height="62" text="{str}"/>
</mx:Application>