Setting the background color on a Spark Application control bar in Flex 4

The following example shows how you can set the background fill color on a Spark Application container’s control bar in Flex 4 by setting the skinClass style and modifying the control bar fill:

<!-- layer 1: control bar fill -->
<s:rect left="1" right="1" top="1" bottom="2">
   <s:fill>
        <s:lineargradient rotation="90">
            <s:gradiententry color="0x333333"></s:gradiententry>
            <s:gradiententry color="0x666666"></s:gradiententry>
        </s:lineargradient>
   </s:fill>
</s:rect>

Full code after the jump.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.

For more information on getting started with Flex 4 and Flash Builder 4, see the official Adobe Flex Team blog.

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/04/setting-the-background-color-on-a-spark-application-control-bar-in-flex-4/ -->
<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"
        backgroundColor="black">
    <s:layout>
        <s:VerticalLayout paddingLeft="20" paddingRight="20"
                paddingTop="20" paddingBottom="20" />
    </s:layout>
    <s:controlBarContent>
        <s:Button label="Button" />
        <s:CheckBox label="CheckBox" />
        <s:RadioButton label="RadioButton" />
        <s:RadioButton label="RadioButton" />
        <s:RadioButton label="RadioButton" />
    </s:controlBarContent>
 
    <fx:Style>
        #topGroup {
            color: white;
        }
    </fx:Style>
 
    <mx:ColorPicker />
    <mx:DateChooser />
 
</s:Application>

And the custom skin class, skins/CustomApplicationSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/04/setting-the-background-color-on-a-spark-application-control-bar-in-flex-4/ -->
<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:State name="normalWithControlBar" />
        <s:State name="disabledWithControlBar" />
    </s:states>
 
    <fx:Metadata>
    <![CDATA[
        [HostComponent("spark.components.Application")]
    ]]>
    </fx:Metadata> 
 
    <!-- fill -->
    <s:Rect id="backgroundRect" left="0" right="0" top="0" bottom="0"  >
        <s:fill>
            <s:SolidColor color="{getStyle('backgroundColor')}" />
        </s:fill>
    </s:Rect>
 
    <s:Group left="0" right="0" top="0" bottom="0">
        <s:layout>
            <s:VerticalLayout gap="0" horizontalAlign="justify" />
        </s:layout>
 
        <s:Group id="topGroup" minWidth="0" minHeight="0"
                    includeIn="normalWithControlBar, disabledWithControlBar" >
            <!-- 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="white" />
                        <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="0x333333" />
                        <s:GradientEntry color="0x666666" />
                    </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:HorizontalLayout 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>

You can also set the skinClass style in an external .CSS file or <Style/> block, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/04/setting-the-background-color-on-a-spark-application-control-bar-in-flex-4/ -->
<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"
        backgroundColor="black">
    <s:layout>
        <s:VerticalLayout paddingLeft="20" paddingRight="20"
                paddingTop="20" paddingBottom="20" />
    </s:layout>
    <s:controlBarContent>
        <s:Button label="Button" />
        <s:CheckBox label="CheckBox" />
        <s:RadioButton label="RadioButton" />
        <s:RadioButton label="RadioButton" />
        <s:RadioButton label="RadioButton" />
    </s:controlBarContent>
 
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
 
        s|Application {
            skinClass: ClassReference("skins.CustomApplicationSkin");
        }
 
        #topGroup {
            color: white;
        }
    </fx:Style>
 
    <mx:ColorPicker />
    <mx:DateChooser />
 
</s:Application>

Or you can set the skinClass style using ActionScript, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/10/04/setting-the-background-color-on-a-spark-application-control-bar-in-flex-4/ -->
<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"
        backgroundColor="black">
    <s:layout>
        <s:VerticalLayout paddingLeft="20" paddingRight="20"
                paddingTop="20" paddingBottom="20" />
    </s:layout>
    <s:controlBarContent>
        <s:Button label="Set skinClass" click="button1_click(event);" />
        <s:CheckBox label="CheckBox" />
        <s:RadioButton label="RadioButton" />
        <s:RadioButton label="RadioButton" />
        <s:RadioButton label="RadioButton" />
    </s:controlBarContent>
 
    <fx:Script>
        <![CDATA[
            import skins.CustomApplicationSkin;
            import mx.core.FlexGlobals;
 
            protected function button1_click(evt:MouseEvent):void {
                FlexGlobals.topLevelApplication.setStyle("skinClass", CustomApplicationSkin);
            }
        ]]>
    </fx:Script>
 
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
 
        #topGroup {
            color: white;
        }
    </fx:Style>
 
    <mx:ColorPicker />
    <mx:DateChooser />
 
</s:Application>

This entry is based on a beta version of the Flex 4 SDK and therefore is very likely to change as development of the Flex SDK continues. The API can (and will) change causing examples to possibly not compile in newer versions of the Flex 4 SDK.