方法一：

  
<?xml version="1.0" encoding="utf-8"?>  
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"    
xmlns:s="library://ns.adobe.com/flex/spark"    
xmlns:mx="library://ns.adobe.com/flex/mx" usePreloader="false">

方法二：

 
    
package com.haso.flex4SH.component  
{  
    import flash.display.Sprite;  
    import flash.events.Event;  
    import flash.events.ProgressEvent;  
        
    import mx.events.FlexEvent;  
    import mx.preloaders.DownloadProgressBar;  
        
    public class pbarunsee extends DownloadProgressBar  
    {  
        public function pbarunsee()  
        {  
            super();  
        }  
        override public function set preloader( preloader:Sprite ):void    {  
            preloader.addEventListener( ProgressEvent.PROGRESS , SWFDownloadProgress );           
            preloader.addEventListener( Event.COMPLETE , SWFDownloadComplete );   
            preloader.addEventListener( FlexEvent.INIT_PROGRESS , FlexInitProgress );   
            preloader.addEventListener( FlexEvent.INIT_COMPLETE , FlexInitComplete );   
        }  
        private function SWFDownloadProgress( event:ProgressEvent ):void {   
            this.visible=false;  
        }   
            
        private function SWFDownloadComplete( event:Event ):void {this.visible=false;}   
            
        private function FlexInitProgress( event:Event ):void {   
            this.visible=false;  
        }   
            
        private function FlexInitComplete( event:Event ):void      
        {               
            dispatchEvent(new Event(Event.COMPLETE));   
        }   
    }  
}  
   
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"   
               xmlns:s="library://ns.adobe.com/flex/spark"   
               xmlns:mx="library://ns.adobe.com/flex/mx"   
               minWidth="955" minHeight="600"  preloader="com.haso.flex4SH.component.pbaru