一个flex进度条

package com.iman.sps.sheet.ascript
{
	import flash.display.Sprite;
	import flash.display.*; 
	import flash.events.*; 
	import flash.filters.BitmapFilterQuality; 
	import flash.filters.BlurFilter; 
	import flash.geom.Matrix; 
	import flash.net.*; 
	import flash.text.TextField; 
	import flash.utils.*; 
	import flash.system.Capabilities; 
	
	import mx.events.*; 

	import mx.preloaders.IPreloaderDisplay;
	
	public class MyProgressBar extends Sprite implements IPreloaderDisplay
	{
		[Embed(source="../image/logo.gif", mimeType="application/octet-stream")] 
		public var _loadingLogo:Class; 
		
		private var dpbImageControl:Loader; 
		private var _barSprite:Sprite; 
		private var progressText:TextField;        
		private var ProgressBarSpritIsAdded:Boolean = false; 

		public function MyProgressBar()
		{
			super();
		}
		
		// Specify the event listeners. 
		public function set preloader(preloader:Sprite):void { 
			//Listen for 正在下载 
			preloader.addEventListener(ProgressEvent.PROGRESS, handleProgress); 
			//Listen for 下载完成 
			preloader.addEventListener(Event.COMPLETE, handleComplete); 
			//Listen for 正在初始化 
			preloader.addEventListener(FlexEvent.INIT_PROGRESS, handleInitProgress); 
			//Listen for 初始化完成 
			preloader.addEventListener(FlexEvent.INIT_COMPLETE, handleInitComplete); 
		} 
		
		// Initialize the Loader control in the override 
		// of IPreloaderDisplay.initialize(). 
		public function initialize():void { 
			//添加logo图 
			dpbImageControl = new Loader();       
			dpbImageControl.contentLoaderInfo.addEventListener(Event.COMPLETE, loader_completeHandler); 
			dpbImageControl.loadBytes(new _loadingLogo() as ByteArray); 
			//dpbImageControl.load(new URLRequest("loadinglogo.swf")); 
		} 
		
		
		// After the SWF file loads, set the size of the Loader control. 
		private function loader_completeHandler(event:Event):void 
		{         
			addChild(dpbImageControl); 
			dpbImageControl.width = 136; 
			dpbImageControl.height= 54; 
			dpbImageControl.x = this.stage.stageWidth/2 - dpbImageControl.width/2; 
			dpbImageControl.y = this.stage.stageHeight/2 - dpbImageControl.height/2 - 40; 
		}   
		
		// 
		private function addProgressBarSprit():void{ 
			//绘制背景渐变 
			var matrix:Matrix=new Matrix(); 
			matrix.createGradientBox(this.stage.stageWidth,this.stage.stageHeight,Math.PI/2); 
			var colors:Array=[0x3399ff,0xFFFFFF]; 
			var alphas:Array=[1,1]; 
			var ratios:Array=[0,255]; 
			this.graphics.lineStyle(); 
			this.graphics.beginGradientFill(GradientType.LINEAR,colors,alphas,ratios,matrix);        
			this.graphics.drawRect(0,0,this.stage.stageWidth,this.stage.stageHeight); 
			this.graphics.endFill(); 
			
			//绘制中心白色发光 
			var _Sprite1:Sprite = new Sprite(); 
			addChild(_Sprite1); 
			_Sprite1.graphics.beginFill(0xffffff,0.45); 
			_Sprite1.graphics.drawEllipse(this.stage.stageWidth/2-130, this.stage.stageHeight/2-90, 280, 100); 
			_Sprite1.graphics.endFill(); 
			//滤镜实现发光边缘柔和            
			var blur:BlurFilter = new BlurFilter(); 
			blur.blurX = 100; 
			blur.blurY = 50; 
			blur.quality = BitmapFilterQuality.HIGH; 
			_Sprite1.filters = [blur]; 
			
			//------------------------------------------------- 
			
			//绘制进度条背景 
			var _Sprite2:Sprite = new Sprite(); 
			addChild(_Sprite2); 
			_Sprite2.graphics.lineStyle(1, 0xCCCCCC); 
			_Sprite2.graphics.beginFill(0xFFFFFF); 
			_Sprite2.graphics.drawRect((this.stage.stageWidth/2 - 152), (this.stage.stageHeight/2 - 10), 304, 20);   
			_Sprite2.graphics.endFill(); 
			
			//------------------------------------------------- 
			
			//加载进度条Sprite 
			_barSprite = new Sprite(); 
			addChild(_barSprite); 
			_barSprite.x = this.stage.stageWidth/2 - 150; 
			_barSprite.y = this.stage.stageHeight/2 - 8; 
			
			//------------------------------------------------- 
			
			//加载进度条文字 
			progressText = new TextField(); 
			addChild(progressText); 
			progressText.textColor = 0x333333; 
			progressText.width = 300; 
			progressText.height = 18; 
			progressText.x = this.stage.stageWidth/2 - 152; 
			progressText.y = this.stage.stageHeight/2 + 20; 
		} 
		
		//刷新进度条 
		private function drawProgressBar(bytesLoaded:Number, bytesTotal:Number):void 
		{   
			if (_barSprite != null && progressText != null){ 
				var g:Graphics = _barSprite.graphics; 
				g.clear(); 
				g.beginFill(0xCCCCCC); 
				g.drawRect(0, 0, 300*(bytesLoaded/bytesTotal),16);   
				g.endFill();    
				
				var matrix:Matrix=new Matrix(); 
				matrix.createGradientBox(300*(bytesLoaded/bytesTotal),16,Math.PI/2); 
				var colors:Array=[0x0099CC,0x99cc77]; 
				var alphas:Array=[1,1]; 
				var ratios:Array=[0,255]; 
				g.lineStyle(); 
				g.beginGradientFill(GradientType.LINEAR,colors,alphas,ratios,matrix);        
				g.drawRect(0,0,300*(bytesLoaded/bytesTotal),16); 
				g.endFill();  
				
				
			} 
		} 
		
		//正在下载的进度 
		private function handleProgress(event:ProgressEvent):void { 
			//第一次处理时绘制进度条Sprit 
			if (ProgressBarSpritIsAdded == false){ 
				ProgressBarSpritIsAdded = true; 
				addProgressBarSprit(); 
			} 
			
			if (progressText != null){ 
				progressText.text = "下载进度：已下载 " + event.bytesLoaded + " byte，总大小 " + event.bytesTotal + " byte."; 
			}         
			drawProgressBar(event.bytesLoaded, event.bytesTotal); 
		} 
		
		private function handleComplete(event:Event):void { 
			if (progressText != null){ 
				progressText.text = "下载完成."; 
			} 
			drawProgressBar(1,1);        
		} 
		
		private function handleInitProgress(event:Event):void { 
			if (progressText != null){ 
				progressText.text = "正在初始化..."; 
			} 
			drawProgressBar(1,1); 
		} 
		
		private function handleInitComplete(event:Event):void { 
			if (progressText != null){ 
				progressText.text = "初始化完成."; 
			} 
			drawProgressBar(1,1);         
			
			//0.03秒后抛出完成事件 
			var timer:Timer = new Timer(300,1); 
			timer.addEventListener(TimerEvent.TIMER, dispatchComplete); 
			timer.start();      
		} 
		
		private function dispatchComplete(event:TimerEvent):void { 
			dispatchEvent(new Event(Event.COMPLETE)); 
		} 

		
		public function get backgroundAlpha():Number
		{
			return 0;
		}
		
		public function set backgroundAlpha(value:Number):void
		{
		}
		
		public function get backgroundColor():uint
		{
			return 0;
		}
		
		public function set backgroundColor(value:uint):void
		{
		}
		
		public function get backgroundImage():Object
		{
			return null;
		}
		
		public function set backgroundImage(value:Object):void
		{
		}
		
		public function get backgroundSize():String
		{
			return null;
		}
		
		public function set backgroundSize(value:String):void
		{
		}
		
		
		
		public function get stageHeight():Number
		{
			return 0;
		}
		
		public function set stageHeight(value:Number):void
		{
		}
		
		public function get stageWidth():Number
		{
			return 0;
		}
		
		public function set stageWidth(value:Number):void
		{
		}
		
		
	}
}

 使用方法：

<?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"
			    preloader="com.iman.sps.sheet.ascript.MyProgressBar">