Creating a semi-transparent scroll bar thumb on an MX TextArea control in Flex 4

By Peter deHaan On April 18, 2010 · 2 Comments

In previous examples, “Creating a custom scroll bar track skin on an MX TextArea control in Flex 4″ and “Creating a custom scroll bar thumb skin on an MX TextArea control in Flex 4″, we saw how we could create a custom scroll bar track and thumb skin on an MX TextArea control in Flex 4 by setting the trackSkin, thumbSkin, verticalScrollBarStyleName, and horizontalScrollBarStyleName styles.

The following example shows how you can create a semi-transparent scroll bar thumb skin on an MX TextArea control in Flex 4 by setting the alpha property on the scroll bar thumb skin part’s fill.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see http://www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see http://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/2010/04/18/creating-a-semi-transparent-scroll-bar-thumb-on-an-mx-textarea-control-in-flex-4/ -->
<s:Application name="MX_TextArea_ScrollBar_thumbSkin_test2"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx">
 
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
        @namespace mx "library://ns.adobe.com/flex/mx";
 
        mx|TextArea {
            verticalScrollBarStyleName: sbTrackStyles;
            horizontalScrollBarStyleName: sbTrackStyles;
        }
 
        .sbTrackStyles {
            thumbSkin: ClassReference("skins.CustomMXScrollBarThumbSkin");
            trackSkin: ClassReference("skins.CustomMXScrollBarTrackSkin");
        }
    </fx:Style>
 
    <mx:TextArea id="txtArea"
            horizontalScrollPolicy="on"
            verticalScrollPolicy="on"
            wordWrap="true"
            horizontalCenter="0" verticalCenter="0"
            width="320" height="240">
        <mx:text><fx:String source="lorem.txt" /></mx:text>
    </mx:TextArea>
 
</s:Application>

The default Spark skins for the MX/Halo controls/containers can be found in the Flex SDK at:
%Flex SDK%\frameworks\projects\sparkskins\src\mx\skins\spark\*.

And the custom MX ScrollBar thumb skin, skins/CustomMXScrollBarThumbSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2010/04/18/creating-a-semi-transparent-scroll-bar-thumb-on-an-mx-textarea-control-in-flex-4/ -->
<s:SparkSkin name="CustomMXScrollBarThumbSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark">
    <!-- states -->
    <s:states>
        <s:State name="up" />
        <s:State name="over" />
        <s:State name="down" />
        <s:State name="disabled" />
    </s:states>
 
    <fx:Script>
        <![CDATA[
            override protected function initializationComplete():void {
                useChromeColor = true;
                super.initializationComplete();
            }
        ]]>
    </fx:Script>
 
    <!-- background -->
    <s:Rect left="0" top="-1" right="0" bottom="-1" minWidth="14">
        <s:stroke>
            <s:SolidColorStroke color="0x5C5C5C" weight="1"/>
        </s:stroke>
        <s:fill>
            <s:SolidColor color="0xFFFFFF" alpha="0.33" />
        </s:fill>
    </s:Rect>
 
    <!-- highlight -->
    <s:Rect left="1" top="0" bottom="0" width="6">
        <s:fill>
            <s:SolidColor color="0xFFFFFF"
                          alpha="0.33"
                          alpha.over="0.22"
                          alpha.down="0.22" />
        </s:fill>
    </s:Rect>
 
    <!-- inside stroke -->
    <s:Rect left="1" top="0" right="1" bottom="0">
        <s:stroke>
            <s:LinearGradientStroke rotation="90" weight="1">
                <s:GradientEntry color="0xFFFFFF" 
                                 alpha="1"
                                 alpha.over="0.55"
                                 alpha.down="0.12" />
                <s:GradientEntry color="0xFFFFFF" 
                                 alpha="0.22" 
                                 alpha.over="0.121" 
                                 alpha.down="0.0264" />
            </s:LinearGradientStroke>
        </s:stroke>
    </s:Rect>
 
    <!-- drop shadow -->
    <s:Rect left="1" top="-2" right="1" height="1">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.12" />
        </s:fill>
    </s:Rect>
    <s:Rect bottom="-3" left="1" right="1" height="2">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.12" />
        </s:fill>
    </s:Rect>
    <s:Rect bottom="-2" left="1" right="1" height="1">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.12" />
        </s:fill>
    </s:Rect>
 
</s:SparkSkin>

And the custom MX ScrollBar track skin, skins/CustomMXScrollBarTrackSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2010/04/18/creating-a-semi-transparent-scroll-bar-thumb-on-an-mx-textarea-control-in-flex-4/ -->
<s:SparkSkin name="CustomMXScrollBarTrackSkin"
             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="up" />
        <s:State name="down" />
        <s:State name="over" />
        <s:State name="disabled" />
    </s:states>
 
    <fx:Script>
        <![CDATA[
            override protected function initializationComplete():void {
                useChromeColor = true;
                super.initializationComplete();
            }
        ]]>
    </fx:Script>
 
    <!-- border/fill -->
    <s:Rect top="0" bottom="0" left="0" right="0"
            minWidth="14" minHeight="14">
        <s:stroke>
            <s:SolidColorStroke color="0x686868" weight="1"/>
        </s:stroke>
        <s:fill>
            <s:BitmapFill source="@Embed('assets/pattern_136.gif')" fillMode="repeat" />
        </s:fill>
    </s:Rect>
 
    <!-- shadow -->
    <s:Rect left="1" top="1" bottom="1" width="1">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.24" />
        </s:fill>
    </s:Rect>
    <s:Rect left="2" top="1" bottom="1" width="1">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.12" />
        </s:fill>
    </s:Rect>
    <s:Rect left="2" right="1" top="1" height="2">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.12" />
        </s:fill>
    </s:Rect>
    <s:Rect left="2" right="1" bottom="1" height="3">
        <s:fill>
            <s:SolidColor color="0x000000" alpha="0.12" />
        </s:fill>
    </s:Rect>
 
</s:SparkSkin>

View source is enabled in the following example.

Background image pattern copyright of Squidfingers.com.

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.

About The Author

Peter deHaan

Peter deHaan currently works for Adobe on the Flex SDK QA team. While not working on Flex, Flash, and ColdFusion applications, Peter enjoys making up bios and writing in 3rd person. Peter's rarely updated blog can be found at blogs.adobe.com/pdehaan/, actionscriptexamples.com, airexamples.com, and coldfusionexamples.com.

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2 Responses to Creating a semi-transparent scroll bar thumb on an MX TextArea control in Flex 4

Paul says:

April 28, 2011 at 3:34 am

Dear All

I have instructed a web development company to build me a website. I asked them to make the scroll bar transparent and they came back to me and said it wasnt possible.

Do you have a site I can pass to them to see it can be done?

How about coding guide on how to achieve this.

Manny thanks
Paul

Reply
- Peter deHaan says:
  
  April 28, 2011 at 8:59 am
  
  @Paul,
  
  Is your website using Flex and the MX TextArea control? If so, send them this page.
  
  Reply

Just a bunch of Adobe Flex Examples

Creating a semi-transparent scroll bar thumb on an MX TextArea control in Flex 4

Peter deHaan

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2 Responses to Creating a semi-transparent scroll bar thumb on an MX TextArea control in Flex 4

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