func pickePhotoFromSheet()

    {

        var sheet:UIActionSheet = UIActionSheet()

        var  button = UIButton.buttonWithType(.Custom) as UIButton

        button.frame  = CGRectMake(0,0,GETSCREENWIDTH,30)

        button.backgroundColor = DefaultWhiteColor

        button.setTitle("相册",forState:UIControlState.Normal)

        button.setTitleColor(COLORWITHRGB(73,73,73), forState: UIControlState.Normal)

        button.setImage(UIImage(named:"icon_album_normal.png"), forState: UIControlState.Normal)

        button.setImage(UIImage(named:"icon_album_active.png"), forState: UIControlState.Highlighted)

      //  button.addTarget(self,action:"photoChoose:",forControlEvents:UIControlEvents.TouchUpInside)

       sheet.addSubview(button)

        sheet.actionSheetStyle  =  UIActionSheetStyle.BlackOpaque

        sheet.showInView(self.view)

    }

UIActionSheet 这样写为什么显示为空白