利用FileReference達到檔案下載

private const FILE_URL:String = "http://yoururltobedownload.zip";
private var fileRef:FileReference;
private var urlReq:URLRequest;

private function init():void {
    urlReq = new URLRequest(FILE_URL);
    fileRef = new FileReference();
    fileRef.addEventListener(Event.CANCEL, doEvent);
    fileRef.addEventListener(Event.COMPLETE, doEvent);
    fileRef.addEventListener(Event.OPEN, doEvent);
    fileRef.addEventListener(Event.SELECT, doEvent);
    fileRef.addEventListener(HTTPStatusEvent.HTTP_STATUS, doEvent);
    fileRef.addEventListener(IOErrorEvent.IO_ERROR, doEvent);
    fileRef.addEventListener(ProgressEvent.PROGRESS, doEvent);
    fileRef.addEventListener(SecurityErrorEvent.SECURITY_ERROR, doEvent);
}

private function doEvent(evt:Event):void {
    var fr:FileReference = evt.currentTarget as FileReference;   
}   

private function download():void {
    fileRef.download(urlReq);
}   

<mx:Button id="downloadBtn" label="Download" click="download()" toolTip="{FILE_URL}" />