在Flex4 Spark Application中设置图片背景解决方案汇总

问题：如何在 Flex4 Spark Application 中添加图片背景？

方案1:自定义含有BitmapGraphic的皮肤类，然后在MXML,CSS,AS中设置skinClass的皮肤样式
<?xml version="1.0" encoding="utf-8"?>
<s:Application name="Spark_Application_skinClass_test"
xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/halo"
skinClass="skins.CustomApplicationSkin">
<s:layout>
<s:BasicLayout />
</s:layout>
</s:Application>

自定义皮肤类, skins/CustomApplicationSkin.mxml代码如下：
<?xml version="1.0" encoding="utf-8"?>
<s:Skin name="CustomApplicationSkin"
xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
alpha.disabled="0.5" >
<s:states>
<s:State name="normal" />
<s:State name="disabled" />
</s:states>

<fx:Metadata>
<![CDATA[
[HostComponent("spark.components.Application")]
]]>
</fx:Metadata>
<!-- fill -->
<s:BitmapImage id="img"
source="@Embed('image1.jpg')"
smooth="true"
left="0" right="0"
top="0" bottom="0" />
<s:Group id="contentGroup" left="0" right="0" top="0" bottom="0" minWidth="0" minHeight="0" />
</s:Skin>

你也可以通过外部.css样式表文件或者使用<Style/>标签来设置使用skinClass样式
<?xml version="1.0" encoding="utf-8"?>
<s:Application name="Spark_Application_skinClass_test"
xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/halo">
<s:layout>
<s:BasicLayout />
</s:layout>

<fx:Style>
@namespace s "library://ns.adobe.com/flex/spark";
s|Application
{
skinClass: ClassReference("skins.CustomApplicationSkin");
}
</fx:Style>
</s:Application>

或者你可以使用ActionScript来设置skinClass样式，代码如下:
<?xml version="1.0" encoding="utf-8"?>
<s:Application name="Spark_Application_skinClass_test"
xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/halo"creationComplete=”init();”>
<fx:Script>
<![CDATA[
import skins.CustomApplicationSkin;

protected function init():void
{
setStyle("skinClass", CustomApplicationSkin);
}
]]>
</fx:Script>
</s:Application>

方案2：在运行时embedded图片到BitmapFill对象中，修改Application皮肤的backgroundRect皮肤部分的填充属性。代码如下:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:ho="library://ns.adobe.com/flex/halo"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"creationComplete="init();">

<fx:Script>
<![CDATA[
import mx.graphics.BitmapFill;

import mx.graphics.BitmapFillMode;

import spark.skins.spark.ApplicationSkin;

[Embed("style/background.jpg")]
protected const BgImg:Class;
protected function init():void
{
var bmpFill : BitmapFill = new BitmapFill();
bmpFill.source = BgImg;
bmpFill.fillMode = BitmapFillMode.SCALE;
ApplicationSkin(skin).backgroundRect.fill=bmpFill;
}
]]>
</fx:Script>
</s:Application>

方案3：扩展默认的Spark包 中Application 皮肤，并通过embedded图片来覆盖backgroundRect皮肤部分的填充属性，代码如下:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:ho="library://ns.adobe.com/flex/halo"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
skinClass="skins.CustomBitmapApplicationSkin">
</s:Application>

扩展的自定义的应用程序皮肤类，skins/CustomBitmapApplicationSkin.as如下：
package skins
{
import mx.graphics.BitmapFill;

import mx.graphics.BitmapFillMode;

import spark.skins.spark.ApplicationSkin;

public class CustomBitmapApplicationSkin extends ApplicationSkin
{
[Embed("style/background.jpg")]
protected const BgImg:Class;

public function CustomBitmapApplicationSkin()
{
super();
var bmpFill:BitmapFill = new BitmapFill();
bmpFill.source=BgImg;
bmpFill.fillMode = BitmapFillMode.SCALE;
backgroundRect.fill = bmpFill;
}
}
}

方案4:自定义皮肤类（有别于方案一,不需要BitmapGraphic）实现代码如下:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:ho="library://ns.adobe.com/flex/halo"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
skinClass="skins.CustomBitmapApplicationSkin2">

<fx:Style>
@namespace s "library://ns.adobe.com/flex/spark";
s|Application
{
backgroundImage: Embed("style/background.jpg");
}

</fx:Style>
</s:Application>

自定义的应用程序皮肤类，skins/CustomBitmapApplicationSkin2.as如下：
<?xml version="1.0" encoding="utf-8"?>
<s:Skin xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:fb="http://ns.adobe.com/flashbuilder/2009"
alpha.disabledStates="0.5">
<s:states>
<s:State name="normal" />
<s:State name="disabled" stateGroups="disabledStates" />
<s:State name="normalWithControlBar" stateGroups="controlBarStates" />
<s:State name="disabledWithControlBar" stateGroups="disabledStates,controlBarStates" />
</s:states>

<fx:Metadata>
[HostComponent("spark.components.Application")]
</fx:Metadata>

<fx:Script fb:purpose="styling">

<![CDATA[
override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
{
backgroundRect.setStyle("backgroundAlpha", getStyle("backgroundAlpha"));
backgroundRect.setStyle("backgroundColor", getStyle("backgroundColor"));
if (getStyle("backgroundImage"))
{
backgroundRect.setStyle("backgroundImage", getStyle("backgroundImage"));
backgroundRect.setStyle("backgroundImageFillMode", "repeat");
}
super.updateDisplayList(unscaledWidth, unscaledHeight);
}

]]>

</fx:Script>
<!-- fill -->

<!---
A rectangle with a solid color fill that forms the background of the application.
The color of the fill is set to the Application's backgroundColor property.
-->
<s:BorderContainer id="backgroundRect"
backgroundColor="#FFFFFF"
borderVisible="false"
left="0" right="0" top="0" bottom="0" />
<s:Group left="0" right="0" top="0" bottom="0">
<s:layout>
<s:VerticalLayout gap="0" horizontalAlign="justify" />
</s:layout>
<!--- Application Control Bar -->
<s:Group id="topGroup"
minWidth="0" minHeight="0"
includeIn="controlBarStates" >
<!-- layer 0: control bar highlight -->
<s:Rect left="0" right="0" top="0" bottom="1" >
<s:stroke>
<s:LinearGradientStroke rotation="90" weight="1">
<s:GradientEntry color="0xFFFFFF" />
<s:GradientEntry color="0xD8D8D8" />
</s:LinearGradientStroke>
</s:stroke>
</s:Rect>
<!-- layer 1: control bar fill -->
<s:Rect left="1" right="1" top="1" bottom="2" >
<s:fill>
<s:LinearGradient rotation="90">
<s:GradientEntry color="0xEDEDED" />
<s:GradientEntry color="0xCDCDCD" />
</s:LinearGradient>
</s:fill>
</s:Rect>
<!-- layer 2: control bar divider line -->
<s:Rect left="0" right="0" bottom="0" height="1" alpha="0.55">
<s:fill>
<s:SolidColor color="0x000000" />
</s:fill>
</s:Rect>
<!-- layer 3: control bar -->
<s:Group id="controlBarGroup"
left="0" right="0" top="1" bottom="1"
minWidth="0" minHeight="0">
<s:layout>
<s:H
4000
orizontalLayout paddingLeft="10" paddingRight="10" paddingTop="7" paddingBottom="7" gap="10" />
</s:layout>
</s:Group>
</s:Group>
<s:Group id="contentGroup"
width="100%" height="100%"
minWidth="0" minHeight="0" />
</s:Group>
</s:Skin>