Flex读文本文件

布局：

<s:Group id="maskGroup" width="503" height="332" x="657" y="165">
        <s:Rect width="100%" height="100%">
            <s:fill>
                <s:SolidColor color="#000000"/>
            </s:fill>
        </s:Rect>
    </s:Group>

<mx:Canvas x="626" y="151" width="565" height="360" backgroundColor="#5976A4"
               horizontalScrollPolicy="off" verticalScrollPolicy="off">
        <s:Scroller id="scrollerId" width="100%" height="100%"
                    horizontalScrollPolicy="off" interactionMode="touch"
                    skinClass="skin.libraryIntroduce.ScrollerSkin">
            <s:Group x="0" y="0" width="565" height="360">
                <s:Label id="introTxt" x="31" y="14" width="503" color="#FFFFFF" fontFamily="微软雅黑"
                         fontSize="20" textAlign="left" verticalAlign="top"
                         mask="{maskGroup}"/>
            </s:Group>
        </s:Scroller>
    </mx:Canvas>

AS:

var file:File=new File("文本文件的绝对路径");
if(file2.exists)
                    {
                        var fileStream:FileStream=new FileStream();
                        fileStream.open(file,FileMode.READ);
    //算高度仅供参考                    
introTxt.height=(Math.floor(Number(fileStream.bytesAvailable/45))+5)*30;
                        introTxt.text=fileStream.readMultiByte(fileStream.bytesAvailable,"gbk");
                        trace(introTxt.height);
                        scrollerId.verticalScrollBar.value=0;
                    }