flex actionScript读取文件

 import flash.events.Event;
 import flash.net.URLLoader;
 import flash.net.URLRequest;
 import flash.net.URLVariables;
 
 public class TxtLoader
 {
  private var setTxt:Function = null;
  public function TxtLoader()
  {
  }
  
  public function loadTxt(fileName:String, setTxt:Function):void {
   this.setTxt = setTxt;
   var urlRequest:URLRequest = new URLRequest(fileName);
   var urlLoader:URLLoader = new URLLoader();
   urlLoader.addEventListener(Event.COMPLETE, complete);
   urlLoader.load(urlRequest);
  }
  
  private function complete(event:Event):void {
   var urlLoader:URLLoader = event.currentTarget as URLLoader;
   setTxt.call(null, urlLoader.data);
  }
 }

-----------------调用的方法-------------------------------------------------------------     

new TxtLoader().loadTxt('readme.txt', function(txt:String):void {  

                  Alert.show( txt);  

        });