在Flex中如果要实现像Html一样的平铺拉伸可能需要自己重写skin组件，默认的flex组件不支持背景图像的平铺功能。以下我是写的一个有关panenl容器的的skin，如果要写canva，Hbox，Application等等的话只需要在原有的基础上稍做修改就可以了，这个组件实现了Html背景平铺拉伸的所有功能，而且可以通过css样式进行设置。以下是源代码，希望对需要的人有所帮助，如不明白欢迎加本人qq：545196225，注明Flex讨论。
一、组件：skin.MyBackgroundSkin
package skin{ import flash.display.Bitmap; import flash.display.BitmapData; import flash.display.DisplayObject; import flash.display.Shape; import flash.geom.Matrix; import mx.core.EdgeMetrics; import mx.core.IChildList; import mx.core.IContainer; import mx.core.IRawChildrenContainer; import mx.core.mx_internal; import mx.skins.halo.PanelSkin; public class MyBackgroundSkin extends PanelSkin { //position信息 private var position:Object; //repeat信息 private var repeat:Object; //背景图片的x坐标 private var bgX:int = 0; //背景图片的y坐标 private var bgY:int = 0; /** * 这个皮肤是专门用来做panel或titleWindow皮肤的 * 如果做HBox，Canvas等容器这部分可以省略去，扩展类写HaloBorder **/ //panel边框信息 private var topH:Number;//panel顶部边框的高度 private var bottomH:Number;//panel底部边框的高度 private var leftW:Number;//panel左边边框的高度 private var rightW:Number;//panel右边边框的高度 public function MyBackgroundSkin() { super(); } //覆盖updateDisplayList方法 override protected function updateDisplayList(w:Number, h:Number):void { super.updateDisplayList(w,h); if(!hasBackgroundImage) { return; } //获取背景图片 var childrenList:IChildList = (parent is IRawChildrenContainer)?(IRawChildrenContainer(parent).rawChildren):IChildList(parent); var backgroundImage:DisplayObject = childrenList.getChildAt(1); //从样式表中获取有关背景平铺的信息 position = getStyle("backgroundImagePosition"); repeat = getStyle("backgroundImageRepeat"); //从样式表中获取panel有关信息 leftW = getStyle("borderThicknessLeft"); rightW = getStyle("borderThicknessRight"); topH = Object(parent).mx_internal::getHeaderHeightProxy() + getStyle("borderThicknessTop");//panel顶部的高度由两部分相加： headerHeigh 和 borderThiknesstop if(getStyle("borderThicknessBottom") == null) { //如果在css中并没有定义该属性的话该属性的默认值有一下两种情况： bottomH = leftW;//(1)当panel中没有向controlBar中添加任何组件 //bottomH = topH;//(2)当panel的controlBar中有控件时候 } else { bottomH = getStyle("borderThicknessBottom"); } //设置默认值 if(repeat == null) { repeat = "no-repeat"; } if(position == null || !(position is Array)) { position = ["left","top"]; } setImagePosition(backgroundImage,w,h); drawRepeat(backgroundImage,w,h); } //设置背景位置 private function setImagePosition(target:DisplayObject,w:Number,h:Number):void { if(position == null || !(position is Array)) { return; } var posHorizontal:String = (position[0] as String).toLowerCase(); var posVertical:String = (position[1] as String).toLowerCase(); //取得边框 var bm:EdgeMetrics = (parent is IContainer)?IContainer(parent).viewMetrics:borderMetrics; //设置背景在x轴的起始位置 switch(posHorizontal) { case "left": bgX = bm.left; break; case "center": //target 默认的位置为剧中 bgX = target.x; break; case "right": bgX = parent.width - bm.right - target.width; break; default: //当传值传传错时候：比如给它传了一个“righ” bgX = leftW; break; } //设置背景在y轴的起始位置 switch(posVertical) { case "top": bgY = bm.top; break; case "middle": //target 默认的位置为剧中 bgY = target.y; break; case "bottom": bgY = parent.height - bm.bottom - target.height; break; default: //当传值传传错时候：比如给它传了一个“righ” bgY = topH; break; } target.x = bgX; target.y = bgY; //设置遮罩位置 const backgroundMask:Shape = Shape(target.mask); backgroundMask.x = bgX; backgroundMask.y = bgY; } //绘制背景图片 private function drawRepeat(target:DisplayObject,w:Number,h:Number):void { if(!hasBackgroundImage) { return; } if(repeat == "no-repeat") { return; } var backgroundImageClass:Class = getStyle("backgroundImage"); var bgImage:DisplayObject = new backgroundImageClass(); //如果背景不是图片 if(!(bgImage as Bitmap)) { return; } //取得背景图片的数据 var backgroundBitmapData:BitmapData = (bgImage as Bitmap).bitmapData; //隐藏默认的背景图片 target.visible = false; //使用矩阵设置背景图片的填充位置 var mtr:Matrix = new Matrix(); //graphics.clear();//如果是给canva，Hbox等皮肤可以去掉该行注释，这样Panel默认的边框就去掉了 //重绘背景图片 switch(repeat) { case "repeat-x": mtr.tx = bgX; mtr.ty = bgY; graphics.beginBitmapFill(backgroundBitmapData,mtr); graphics.drawRect(bgX,bgY,w - rightW - bgX,bgImage.height); break; case "repeat-y": mtr.tx = bgX; mtr.ty = bgY; graphics.beginBitmapFill(backgroundBitmapData,mtr); graphics.drawRect(bgX,bgY,bgImage.width,h - bottomH - bgY); break; case "repeat": mtr.tx = bgX; mtr.ty = bgY; graphics.beginBitmapFill(backgroundBitmapData,mtr); graphics.drawRect(bgX,bgY,w - rightW - bgX,h - bottomH - bgY); break; default: mtr.tx = leftW; mtr.ty = topH; graphics.beginBitmapFill(backgroundBitmapData,mtr); graphics.drawRect(bgX,bgY,w - rightW - bgX,h - bottomH - bgY); break; } graphics.endFill(); } }}
二、主程序：
<?xml version="1.0" encoding="utf-8"?><mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"><mx:Style> .panel { border-skin:ClassReference('skin.MyBackgroundSkin'); background-image:Embed("frage.png"); backgroundImagePosition:left,top;/*第一个参数可用值：left,center,right,默认值left;第二个参数可用值：top,middle,bottom,默认值top*/ backgroundImageRepeat:repeat;/*可用值：repeat,no-repeat,repeat-x,repeat-y,默认值no-repeat*/ background-size:100; border-thickness-bottom:30; border-thickness-left:30; border-thickness-right:30; border-thickness-top:30; header-height:30; }</mx:Style> <mx:Panel x="225" y="222" width="759" height="509" layout="absolute" styleName="panel"> </mx:Panel></mx:Application>