Removing the vertical separator from the Spark DropDownList control in Flex 4

In a previous example, “Removing the vertical separator from the ComboBox control in Flex”, we saw how you could remove the vertical separator from the Flex ComboBox control by creating a custom ComboBox skin using ActionScript.

The following example shows how you can remove the vertical separator from the Spark DropDownList control in Flex 4 by creating a custom skin and setting the skinClass style.

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/2009/04/18/removing-the-vertical-separator-from-the-spark-dropdownlist-control-in-flex-gumbo/ -->
<s:Application name="Spark_DropDownList_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:DropDownList id="dropDownList"
            prompt="Please select a thing..."
            labelField="label"
            skinClass="skins.CustomDropDownListSkin"
            horizontalCenter="0"
            top="20">
        <s:dataProvider>
            <s:ArrayList>
                <fx:Object label="One" />
                <fx:Object label="Two" />
                <fx:Object label="Three" />
                <fx:Object label="Four" />
                <fx:Object label="Five" />
                <fx:Object label="Six" />
                <fx:Object label="Seven" />
                <fx:Object label="Eight" />
                <fx:Object label="Nine" />
            </s:ArrayList>
        </s:dataProvider>
    </s:DropDownList>
 
</s:Application>

The custom DropDownList control skin, skins/CustomDropDownListSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/04/18/removing-the-vertical-separator-from-the-spark-dropdownlist-control-in-flex-gumbo/ -->
<s:Skin name="CustomDropDownListSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        alpha.disabled="0.5">
    <!-- states -->
    <s:states>
        <s:State name="normal" />
        <s:State name="open" />
        <s:State name="disabled" />
    </s:states>
 
    <!-- host component -->
    <fx:Metadata>
    <![CDATA[
        [HostComponent("spark.components.DropDownList")]
    ]]>
    </fx:Metadata>
 
    <!--- The PopUpAnchor control that opens the drop-down list. -->
    <s:PopUpAnchor id="popUp" displayPopUp.normal="false" displayPopUp.open="true" includeIn="open"
            left="0" right="0" top="0" bottom="0" itemDestructionPolicy="auto"
            popUpPosition="below" popUpWidthMatchesAnchorWidth="true">
        <!--- The drop down area of the skin. This includes borders, background colors, scrollers, and filters. -->
        <s:Group id="dropDown" maxHeight="134" minHeight="22" >
            <!-- drop shadow -->
            <s:RectangularDropShadow blurX="20" blurY="20" alpha="1.0" distance="5"
                    angle="90" color="#000000" left="0" top="0" right="0" bottom="0"/>
 
            <!-- border -->
            <s:Rect left="0" right="0" top="0" bottom="0">
                <s:stroke>
                    <s:SolidColorStroke color="0x686868" weight="1"/>
                </s:stroke>
            </s:Rect>
 
            <!-- fill -->
            <!--- Defines the appearance of drop-down list's background fill. -->
            <s:Rect id="background" left="1" right="1" top="1" bottom="1" >
                <s:fill>
                    <!--- The color of the drop down's background fill. The default color is 0xFFFFFF. -->
                    <s:SolidColor id="bgFill" color="0xFFFFFF" />
                </s:fill>
            </s:Rect>
 
            <s:Scroller left="0" top="0" right="0" bottom="0" focusEnabled="false" minViewportInset="1">
                <!--- The container for the data items in the drop-down list. -->
                <s:DataGroup id="dataGroup" itemRenderer="spark.skins.spark.DefaultItemRenderer">
                    <s:layout>
                        <s:VerticalLayout gap="0" horizontalAlign="contentJustify"/>
                    </s:layout>
                </s:DataGroup>
            </s:Scroller>
        </s:Group>
    </s:PopUpAnchor>
 
    <!--- The anchor button used by the DropDownList. The default skin is DropDownListButtonSkin. -->
    <s:Button id="openButton" left="0" right="0" top="0" bottom="0" focusEnabled="false"
            skinClass="skins.CustomDropDownListButtonSkin" />
    <!--- The prompt area of the DropDownList. -->
    <s:SimpleText id="labelDisplay" verticalAlign="middle" maxDisplayedLines="1"
            left="7" right="30" top="2" bottom="2" verticalCenter="1" />
 
</s:Skin>

And the custom DropDownList Button control skin, skins/CustomDropDownListButtonSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/04/18/removing-the-vertical-separator-from-the-spark-dropdownlist-control-in-flex-gumbo/ -->
<s:SparkSkin name="CustomDropDownListButtonSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark" 
        minWidth="21" minHeight="21">
    <!-- states -->
    <s:states>
        <s:State name="up" />
        <s:State name="over" />
        <s:State name="down" />
        <s:State name="disabled" />
    </s:states>
 
    <fx:Metadata>
    <![CDATA[
        [HostComponent("spark.components.Button")]
    ]]>
    </fx:Metadata>
 
     <fx:Script>
        /* Define the skin elements that should not be colorized. 
           For dropDownList buttons, the graphics are colorized but the arrow is not. */
        static private const exclusions:Array = ["arrow"];
 
        override public function get colorizeExclusions():Array {return exclusions;}
 
        /* Define the symbol fill items that should be colored by the "symbolColor" style. */
        static private const symbols:Array = ["arrowFill1", "arrowFill2"];
 
        override public function get symbolItems():Array {return symbols};
    </fx:Script>
 
    <!-- layer 1: shadow -->
    <s:Rect left="-1" right="-1" top="-1" bottom="-1" radiusX="2" radiusY="2">
        <s:fill>
            <s:LinearGradient rotation="90">
                <s:GradientEntry color="0x000000" 
                        color.down="0xFFFFFF"
                        alpha="0.01"
                        alpha.down="0" />
                <s:GradientEntry color="0x000000" 
                        color.down="0xFFFFFF" 
                        alpha="0.07"
                        alpha.down="0.5" />
            </s:LinearGradient>
        </s:fill>
    </s:Rect>
 
    <!-- layer 2: fill -->
    <s:Rect left="1" right="1" top="1" bottom="1" radiusX="2" radiusY="2">
        <s:fill>
            <s:LinearGradient rotation="90">
                <s:GradientEntry color="0xFFFFFF" 
                        color.over="0xBBBDBD" 
                        color.down="0xAAAAAA" 
                        alpha="0.85" />
                <s:GradientEntry color="0xD8D8D8" 
                        color.over="0x9FA0A1" 
                        color.down="0x929496" 
                        alpha="0.85" />
            </s:LinearGradient>
        </s:fill>
    </s:Rect>
 
    <!-- layer 3: fill lowlight -->
    <s:Rect left="1" right="1" bottom="1" height="9" radiusX="2" radiusY="2">
        <s:fill>
            <s:LinearGradient rotation="90">
                <s:GradientEntry color="0x000000" alpha="0.0099" />
                <s:GradientEntry color="0x000000" alpha="0.0627" />
            </s:LinearGradient>
        </s:fill>
    </s:Rect>
 
    <!-- layer 4: fill highlight -->
    <s:Rect left="1" right="1" top="1" height="9" radiusX="2" radiusY="2">
        <s:fill>
            <s:SolidColor color="0xFFFFFF" 
                        alpha="0.33" 
                        alpha.over="0.22" 
                        alpha.down="0.12" />
        </s:fill>
    </s:Rect>
 
    <!-- layer 5: highlight stroke (all states except down) -->
    <s:Rect left="1" right="1" top="1" bottom="1" radiusX="2" radiusY="2" excludeFrom="down">
        <s:stroke>
            <s:LinearGradientStroke rotation="90" weight="1">
                <s:GradientEntry color="0xFFFFFF" alpha.over="0.22" />
                <s:GradientEntry color="0xD8D8D8" alpha.over="0.22" />
            </s:LinearGradientStroke>
        </s:stroke>
    </s:Rect>
 
    <!-- layer 6: highlight stroke (down state only) -->
    <s:Rect left="1" top="1" bottom="1" width="1" includeIn="down">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.07" />
        </s:fill>
    </s:Rect>
    <s:Rect right="1" top="1" bottom="1" width="1" includeIn="down">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.07" />
        </s:fill>
    </s:Rect>
    <s:Rect left="2" top="1" right="2" height="1" includeIn="down">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.25" />
        </s:fill>
    </s:Rect>
    <s:Rect left="1" top="2" right="1" height="1" includeIn="down">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.09" />
        </s:fill>
    </s:Rect>
 
    <!-- layer 7: border - put on top of the fill so it doesn't disappear when scale is less than 1 -->
    <s:Rect left="0" right="0" top="0" bottom="0" width="69" height="20" radiusX="2" radiusY="2">
        <s:stroke>
            <s:LinearGradientStroke rotation="90" weight="1">
                <s:GradientEntry color="0x000000" 
                               alpha="0.5625"
                               alpha.down="0.6375" />
                <s:GradientEntry color="0x000000" 
                               alpha="0.75" 
                               alpha.down="0.85" />
            </s:LinearGradientStroke>
        </s:stroke>
    </s:Rect>
 
    <!-- layer 8: arrow -->
    <!--- The arrow graphic displayed in the anchor button. -->
    <s:Path right="6" verticalCenter="0" id="arrow"
            data="M 4.0 4.0 L 4.0 3.0 L 5.0 3.0 L 5.0 2.0 L 6.0 2.0 L 6.0 1.0 L 7.0 1.0 L 7.0 0.0 L 0.0 0.0 L 0.0 1.0 L 1.0 1.0 L 1.0 2.0 L 2.0 2.0 L 2.0 3.0 L 3.0 3.0 L 3.0 4.0 L 4.0 4.0">
        <s:fill>
             <s:RadialGradient rotation="90" focalPointRatio="1">
                <!--- The first part of the arrow's gradient fill. The default alpha is .6. The default color if 0x000000. -->
                <s:GradientEntry id="arrowFill1" color="0" alpha="0.6" />
                <!--- The second part of the arrow's gradient fill. The default alpha is .6. The default color if 0x000000. -->
                <s:GradientEntry id="arrowFill2" color="0" alpha="0.8" />
            </s:RadialGradient>
        </s:fill>
    </s:Path>
 
</s:SparkSkin>

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.

3 thoughts on “Removing the vertical separator from the Spark DropDownList control in Flex 4

  1. In the examples with mxml files that define a SparkSkin, I need to know were to locate the skin files so that they are found during compilation. I sure this is obvious to others, but I’m new to both flex and gumbo. (I am having great fun playing with these examples, though) I’m using Flex Builder 3 to implement the examples. Thanks.

  2. Bill Winkelman,

    Your folder layout for the above example should look like the following:
    main.mxml
    skins/CustomDropDownListSkin.mxml
    skins/CustomDropDownListButtonSkin.mxml

    If you want to find the default Spark skins, look in the following Flex SDK folder:
    <flex sdk>\frameworks\projects\flex4\src\spark\skins\default\…

    Peter

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