Creating a custom Spark HSlider thumb in Flex 4

The following example shows how you can use a Spark Button control as a thumb for the Spark HSlider control by setting the skinClass style on the thumb skin part in a custom Spark HSlider control skin.

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/2010/04/23/creating-a-custom-spark-hslider-thumb-in-flex-4/ -->
<s:Application name="Spark_HSlider_thumb_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/mx"> 
    <s:controlBarContent>
        <mx:Form>
            <mx:FormItem label="red:">
                <s:HSlider id="rSl"
                        maximum="0xFF"
                        skinClass="skins.CustomHSliderSkin"
                        showDataTip="false"
                        change="setFillColor(rSl.value, gSl.value, bSl.value);" />
            </mx:FormItem>
            <mx:FormItem label="green:">
                <s:HSlider id="gSl"
                        maximum="0xFF"
                        skinClass="skins.CustomHSliderSkin"
                        showDataTip="false"
                        change="setFillColor(rSl.value, gSl.value, bSl.value);" />
            </mx:FormItem>
            <mx:FormItem label="blue:">
                <s:HSlider id="bSl"
                        maximum="0xFF"
                        skinClass="skins.CustomHSliderSkin"
                        showDataTip="false"
                        change="setFillColor(rSl.value, gSl.value, bSl.value);" />
            </mx:FormItem>
        </mx:Form>
    </s:controlBarContent>
 
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
        @namespace mx "library://ns.adobe.com/flex/mx";
 
        #rSl s|Button#track {
            chromeColor: red;
        }
 
        #gSl s|Button#track {
            chromeColor: green;
        }
 
        #bSl s|Button#track {
            chromeColor: blue;
        }
    </fx:Style>
 
    <fx:Script>
        <![CDATA[
            private function setFillColor(r:uint, g:uint, b:uint):void {
                var colour:Number = (r << 16) ^ (g << 8) ^ b;
                solidFill.color = colour;
            }
        ]]>
    </fx:Script>
 
    <s:Rect id="rct"
            left="40" right="40" top="40" bottom="40">
        <s:fill>
            <s:SolidColor id="solidFill" />
        </s:fill>
    </s:Rect>
 
</s:Application>

And the custom Spark HSlider skin, skins/CustomHSliderSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2010/04/23/creating-a-custom-spark-hslider-thumb-in-flex-4/ -->
<s:SparkSkin name="CustomHSliderSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:fb="http://ns.adobe.com/flashbuilder/2009"
        minHeight="11"
        alpha.disabled="0.5">
    <!-- states -->
    <s:states>
        <s:State name="normal" />
        <s:State name="disabled" />
    </s:states>
 
    <fx:Metadata>
        [HostComponent("spark.components.HSlider")]
    </fx:Metadata> 
 
    <fx:Script fb:purpose="styling">
        <![CDATA[
            /* Define the skin elements that should not be colorized. 
               For slider, the skin itself is colorized but the individual parts are not. */
            static private const exclusions:Array = ["track", "thumb"];
 
            override public function get colorizeExclusions():Array {
                return exclusions;
            }
 
            override protected function initializationComplete():void {
                useChromeColor = true;
                super.initializationComplete();
            }
        ]]>
    </fx:Script>
 
    <fx:Script>
        <![CDATA[
            override protected function measure() : void {
                // Temporarily move the thumb to the left of the Slider so measurement
                // doesn't factor in its x position. This allows resizing the
                // HSlider to less than 100px in width. 
                var thumbPos:Number = thumb.getLayoutBoundsX();
                thumb.setLayoutBoundsPosition(0, thumb.getLayoutBoundsY());
                super.measure();
                thumb.setLayoutBoundsPosition(thumbPos, thumb.getLayoutBoundsY());
            }
        ]]>
    </fx:Script>
 
    <fx:Declarations>
        <!--- The tooltip used in the mx.controls.Slider control. 
               To customize the DataTip's appearance, create a custom HSliderSkin class.-->
        <fx:Component id="dataTip">     
           <s:DataRenderer minHeight="24" minWidth="40" y="-34">  
              <s:Rect top="0" left="0" right="0" bottom="0">
                    <s:fill>
                        <s:SolidColor color="0x000000" alpha=".9"/>
                    </s:fill>
                    <s:filters>
                        <s:DropShadowFilter angle="90" color="0x999999" distance="3"/>
                    </s:filters>
                </s:Rect>
                <s:Label id="labelDisplay" text="{data}"
                         horizontalCenter="0" verticalCenter="1"
                         left="5" right="5" top="5" bottom="5"
                         textAlign="center" verticalAlign="middle"
                         fontWeight="normal" color="white" fontSize="11" />
            </s:DataRenderer>
       </fx:Component>
    </fx:Declarations>
 
    <!--- The default skin class is HSliderTrackSkin. -->
    <s:Button id="track" left="0" right="0" top="0" bottom="0" minWidth="33" width="100"
              skinClass="spark.skins.spark.HSliderTrackSkin" />
 
    <!--- The default skin class is HSliderThumbSkin. -->
    <s:Button id="thumb" top="0" bottom="0" 
              skinClass="spark.skins.spark.ButtonSkin"
              label="{hostComponent.value.toString(16).toUpperCase()}"
              width="40" />
</s:SparkSkin>

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View source is enabled in the following example.

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.

2 thoughts on “Creating a custom Spark HSlider thumb in Flex 4

  1. How can I have two thumbs on an hslider in Flex 4?
    There is no property ‘thumbCount’ as in flex 3.

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