Flex 加载进度条

<?xml version="1.0" encoding="utf-8"?><mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"        layout="vertical"        verticalAlign="middle"        backgroundColor="white">    <mx:Script>    <![CDATA[      private var timer:Timer;            private function init():void {        timer = new Timer(10);        timer.addEventListener(TimerEvent.TIMER, timer_timer);      }            private function timer_timer(evt:TimerEvent):void {        progressBar.setProgress(progressBar.value + 1, 100);      }            private function progressBar_complete(evt:Event):void {        timer.stop();      }            private function resetProgressBar():void {        progressBar.setProgress(0, 100);        progressBar.scaleX = 1.0; // 100%        progressBar.scaleY = 1.0; // 100%        progressBar.alpha = 1.0; // 100%      }            private function playProgressBar():void {        resetProgressBar();        timer.start();      }    ]]>  </mx:Script>    <mx:Parallel id="progressBar_completeEffect">    <mx:Fade alphaTo="0.0" />    <mx:Zoom zoomHeightTo="0" />  </mx:Parallel>    <mx:ApplicationControlBar dock="true">        <mx:Button label="Play"             click="playProgressBar();" />        <mx:Button label="Reset"             click="resetProgressBar();" />      </mx:ApplicationControlBar>  <mx:ProgressBar id="progressBar"          complete="progressBar_complete(event);"          completeEffect="{progressBar_completeEffect}"          mode="manual"          labelPlacement="center"          width="80%"          height="60%"          creationComplete="init();" />  </mx:Application>