Disabling specific buttons in a Spark ButtonBar control in Flex 4

The following example shows how you can disable specific buttons in a Spark ButtonBar control in Flex 4 by using 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/2009/08/01/disabling-specific-buttons-in-a-spark-buttonbar-control-in-flex-4/ -->
<s:Application name="Spark_ButtonBar_ButtonBarButton_enabled_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark">
 
    <s:ButtonBar id="btnBar"
            labelField="label"
            requireSelection="true"
            skinClass="skins.CustomButtonBarSkin"
            horizontalCenter="0" verticalCenter="0">
        <s:dataProvider>
            <s:ArrayList>
                <fx:Object label="Button 1" />
                <fx:Object id="obj2" label="Button 2" enabled="false" />
                <fx:Object label="Button 3" enabled="true" />
                <fx:Object label="Button 4" enabled="false" />
            </s:ArrayList>
        </s:dataProvider>
    </s:ButtonBar>
 
</s:Application>

View source is enabled in the following example.

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The custom Spark ButtonBar skin class, skins/CustomButtonBarSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/08/01/disabling-specific-buttons-in-a-spark-buttonbar-control-in-flex-4/ -->
<s:Skin name="CustomButtonBarSkin"
        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="disabled" />
    </s:states>
 
    <fx:Metadata>
        <![CDATA[
            [HostComponent("spark.components.ButtonBar")]
        ]]>
    </fx:Metadata>
 
    <fx:Declarations>
        <fx:Component id="middleButton" >
            <s:ButtonBarButton skinClass="skins.CustomButtonBarMiddleButtonSkin" />
        </fx:Component>
    </fx:Declarations>
 
    <s:DataGroup id="dataGroup" width="100%" height="100%">
        <s:layout>
            <s:ButtonBarHorizontalLayout gap="-1"/>
        </s:layout>
    </s:DataGroup>
 
</s:Skin>

And the custom Spark ButtonBarButton skin class, skins/CustomButtonBarMiddleButtonSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/08/01/disabling-specific-buttons-in-a-spark-buttonbar-control-in-flex-4/ -->
<s:SparkSkin name="CustomButtonBarMiddleButtonSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        minWidth="21" minHeight="21"
        alpha.disabledStates="0.5"
        creationComplete="init();">
    <!-- states -->
    <s:states>
        <s:State name="up" />
        <s:State name="over" stateGroups="overStates" />
        <s:State name="down" stateGroups="downStates" />
        <s:State name="disabled" stateGroups="disabledStates" />
        <s:State name="upAndSelected" stateGroups="selectedStates, selectedUpStates" />
        <s:State name="overAndSelected" stateGroups="overStates, selectedStates" />
        <s:State name="downAndSelected" stateGroups="downStates, selectedStates" />
        <s:State name="disabledAndSelected" stateGroups="selectedUpStates, disabledStates, selectedStates" />
    </s:states>
 
    <!-- host component -->
    <fx:Metadata>
        <![CDATA[
            [HostComponent("spark.components.ButtonBarButton")]
        ]]>
    </fx:Metadata>
 
    <fx:Script>
        /* Define the skin elements that should not be colorized.
        For toggle button, the graphics are colorized but the label is not. */
        static private const exclusions:Array = ["labelDisplay"];
 
        override public function get colorizeExclusions():Array {return exclusions;}
 
        protected function init():void {
            try {
                if (hostComponent.data.hasOwnProperty("enabled")) {
                    hostComponent.enabled = hostComponent.data.enabled;
                }
            } catch (err:*) {
                // ignore
            }
        }
    </fx:Script>
 
    <!-- layer 1: shadow -->
    <s:Rect left="0" right="0" bottom="-1" height="1">
        <s:fill>
            <s:SolidColor color="0x000000"
                    color.downStates="0xFFFFFF"
                    alpha="0.07"
                    alpha.downStates="0.5" />
        </s:fill>
    </s:Rect>
 
    <!-- layer 2: fill -->
    <s:Rect left="1" right="1" top="1" bottom="1">
        <s:fill>
            <s:LinearGradient rotation="90">
                <s:GradientEntry color="0xFFFFFF"
                        color.selectedUpStates="0xBBBDBD"
                        color.overStates="0xBBBDBD"
                        color.downStates="0xAAAAAA"
                        alpha="0.85"
                        alpha.overAndSelected="1" />
                <s:GradientEntry color="0xD8D8D8"
                        color.selectedUpStates="0x9FA0A1"
                        color.over="0x9FA0A1"
                        color.overAndSelected="0x8E8F90"
                        color.downStates="0x929496"
                        alpha="0.85"
                        alpha.overAndSelected="1" />
            </s:LinearGradient>
        </s:fill>
    </s:Rect>
 
    <!-- layer 3: fill lowlight -->
    <s:Rect left="1" right="1" bottom="1" height="9">
        <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">
        <s:fill>
            <s:SolidColor color="0xFFFFFF"
                    alpha="0.33"
                    alpha.selectedUpStates="0.22"
                    alpha.overStates="0.22"
                    alpha.downStates="0.12" />
        </s:fill>
    </s:Rect>
 
    <!-- layer 5: highlight stroke (all states except down) -->
    <s:Rect left="1" right="1" top="1" bottom="1" excludeFrom="downStates">
        <s:stroke>
            <s:LinearGradientStroke rotation="90" weight="1">
                <s:GradientEntry color="0xFFFFFF" alpha.overStates="0.22" alpha.selectedUpStates="0.33" />
                <s:GradientEntry color="0xD8D8D8" alpha.overStates="0.22" alpha.selectedUpStates="0.33" />
            </s:LinearGradientStroke>
        </s:stroke>
    </s:Rect>
 
    <!-- layer 6: highlight stroke (down state only) -->
    <s:Rect left="1" top="1" bottom="1" width="1" includeIn="downStates, selectedUpStates, overAndSelected">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.07" />
        </s:fill>
    </s:Rect>
    <s:Rect right="1" top="1" bottom="1" width="1" includeIn="downStates, selectedUpStates, overAndSelected">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.07" />
        </s:fill>
    </s:Rect>
    <s:Rect left="1" top="1" right="1" height="1" includeIn="downStates, selectedUpStates, overAndSelected">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.25" />
        </s:fill>
    </s:Rect>
    <s:Rect left="1" top="2" right="1" height="1" includeIn="downStates, selectedUpStates, overAndSelected">
        <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">
        <s:stroke>
            <s:LinearGradientStroke rotation="90" weight="1">
                <s:GradientEntry color="0x000000"
                                 alpha="0.5625"
                                 alpha.down="0.6375"
                                 alpha.selectedStates="0.6375" />
                <s:GradientEntry color="0x000000"
                                 alpha="0.75"
                                 alpha.down="0.85"
                                 alpha.selectedStates="0.85" />
            </s:LinearGradientStroke>
        </s:stroke>
    </s:Rect>
 
    <!-- layer 8: text -->
    <!--- Defines the appearance of the label(s) for the middle button(s) in the ButtonBar component. -->
    <s:SimpleText id="labelDisplay"
                  textAlign="center"
                  verticalAlign="middle"
                  maxDisplayedLines="1"
                  horizontalCenter="0" verticalCenter="1"
                  left="10" right="10" top="2" bottom="2" />
 
</s:SparkSkin>

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.

6 thoughts on “Disabling specific buttons in a Spark ButtonBar control in Flex 4

  1. If you want to be able to enable/disable the button at runtime you need to tweak the code in the custom skin class to listen for changes in the host component. Now whenever the ‘enabled’ property changes the button will update accordingly.

    private function init():void 
    {
    	hostComponent.addEventListener(FlexEvent.VALUE_COMMIT, onDataChange);
    	onDataChange();
    }
     
    private function onDataChange(event:FlexEvent=null):void 
    {		
    	if (hostComponent.data.hasOwnProperty("enabled"))
    	{
    		hostComponent.enabled = hostComponent.data.enabled;
     
    	}
    }
  2. @Derrick: Thank you, thank you! Adding that code to a tab bar button skin allowed me to disable that button by setting the enabled of a NavigatorContent in a bound viewstack to false.

  3. Hello, Thanks for the tips! I’m having trouble programmatically enabling/disabling the buttons. It appears that the VALUE_COMMIT event only gets triggered when the user actually clicks on the button. Is there any way to disable a button without having to click on it?

  4. To answer Erica’s question for others who may come across this: Instead of setting the event listener in Derrick Grigg’s example to FlexEvent.VALUE_COMMIT, set it to FlexEvent.UPDATE_COMPLETE. it will refresh the status more frequently, but shouldn’t represent an issue.

  5. Hmm very gud example as i have tried doin this through the enable property of tabbar but didn’t work out but when i use your method i get arror

    The required skin part ‘middleButton’ is missing.
    The required skin state ‘disabled’ is missing.
    The required skin state ‘normal’ is missing.

    any IDEA?

    Any help wpuld be appriciated thnks in advanced!

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