Flex制作的swf加载时的设置样本

package com
{
 import flash.display.*;
 import flash.events.*;
 import flash.net.*;
 import flash.text.TextField;
 import flash.text.TextFormat;
 
 import mx.events.FlexEvent;
 import mx.preloaders.DownloadProgressBar;
 
 public class LoadingExampleProgressBar extends DownloadProgressBar
 {
  private var logo:Loader;
  private var txt:TextField;
  private var _preloader:Sprite;
  public function LoadingExampleProgressBar()
  {
   logo = new Loader();
   logo.load(new URLRequest("l4cd.png"));
   addChild(logo);
   
   var style:TextFormat = new TextFormat(null,null,0xFFFFFF,null,null,null,null,null,"center");
   txt = new TextField();
   txt.defaultTextFormat = style;
   txt.width = 200;
   txt.selectable = false;
   txt.height = 20;
   addChild(txt);
   
   super();
  }
  //最重要的代码就在这里..重写preloader,让swf执行加载的时候~进行你希望的操作~
  override public function set preloader(value:Sprite):void{
   _preloader = value
   //四个侦听~分别是 加载进度 / 加载完毕 / 初始化进度 / 初始化完毕
   _preloader.addEventListener(ProgressEvent.PROGRESS,load_progress);
   _preloader.addEventListener(Event.COMPLETE,load_complete);
   _preloader.addEventListener(FlexEvent.INIT_PROGRESS,init_progress);
   _preloader.addEventListener(FlexEvent.INIT_COMPLETE,init_complete);

 

  //add by huanghui  . It's imposable!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   _preloader.visible = false;

  //_preloader.alpha = 0;

  //_preloader.cacheAsBitmap = true;

   stage.addEventListener(Event.RESIZE,resize)
   resize(null);
  }
  private function remove():void{
   _preloader.removeEventListener(ProgressEvent.PROGRESS,load_progress);
   _preloader.removeEventListener(Event.COMPLETE,load_complete);
   _preloader.removeEventListener(FlexEvent.INIT_PROGRESS,init_progress);
   _preloader.removeEventListener(FlexEvent.INIT_COMPLETE,init_complete);
   stage.removeEventListener(Event.RESIZE,resize)
  }
  private function resize(e:Event):void{
   logo.x = (stage.stageWidth - 40)/2;
   logo.y = (stage.stageHeight - 80)/2;
   txt.x = (stage.stageWidth - 200)/2;
   txt.y = logo.y + 40+5;
   
   graphics.clear();
   graphics.beginFill(0x333333);
   graphics.drawRect(0,0,stage.stageWidth,stage.stageHeight);
   graphics.endFill();
  }
  private function load_progress(e:ProgressEvent):void{
   //txt.text = "正在加载..."+int(e.bytesLoaded/e.bytesTotal*100)+"%";
  }
  private function load_complete(e:Event):void{
   //txt.text = "加载完毕!"
  }
  private function init_progress(e:FlexEvent):void{
   ///txt.text = "正在初始化..."
  }
  private function init_complete(e:FlexEvent):void{
   //txt.text = "初始化完毕!"
   remove()
   //最后这个地方需要dpe一个Event.COMPLETE事件..表示加载完毕让swf继续操作~
   dispatchEvent(new Event(Event.COMPLETE))
  }
 }
}

在src下，新建一个包，命名为com，在com下新建一个as文件，名为LoadingExampleProgressBar.as，将以上代码复制到as文件中并保存，然后再mxml文件的头部<s:Application   ...   >中添加preloader="com.LoadingExampleProgressBar"，编译运行即得结果。