Question

How can I have a constant in a Flex application which I could apply at several places in a Flex CSS file? For example I may have a background color which is the same in several UI components and then I would like to have this color set in only one place and reused in all style clauses. Something like …

public static const myColor = "#00FF00"

...

component1 
{
  backgroundColor: myColor
}

component2 {
  backgroundColor: myColor
}

Answer 1

This is what I use. Check out the StylesheetMixin class on Snipplr.

This is what it looks like in use:

ColorPalette

package
{
    // only make bindable if you want to use in skins
    // for example like color="{ColorPalette.crazyColor}"
    [Bindable]
    /**
     *  This class holds all of your global colors to apply to skins.
     */
    public class ColorPalette
    {
        // "var", not "const", so you can optionally change them at runtime
        public static var crazyColor:uint = 0xff0000;
        public static const applicationAccent:uint = 0x1a01dd;
    }   
}

Stylesheet

@namespace mx "library://ns.adobe.com/flex/mx";
@namespace s "library://ns.adobe.com/flex/spark";
@namespace tlf "library://ns.adobe.com/flashx/textLayout";

mx|Panel
{
    color: crazyColor;
    backgroundColor: applicationAccent;
}
mx|Button
{
    color: crazyColor;
    backgroundColor: applicationAccent;
}

Flex 3 equivalent:

Panel
{
    color: crazyColor;
    backgroundColor: applicationAccent;
}
Button
{
    color: crazyColor;
    backgroundColor: applicationAccent;
}   

Sample Application

<?xml version="1.0" encoding="utf-8"?>
<mx:Application
    xmlns:mx="http://www.adobe.com/2006/mxml"
    xmlns:local="*">

    <mx:Script>
        <![CDATA[
            import ColorPalette;
        ]]>
    </mx:Script>

    <!-- simple css -->
    <mx:Style source="main.css"/>

    <!-- stylesheet palette -->
    <local:StylesheetMixin palettes="{[ColorPalette]}"/>

    <!-- sample container -->
    <mx:Panel id="panel" width="100%" height="100%" title="Stylesheet Palettes!">
        <mx:Button label="Button"/>
    </mx:Panel>

</mx:Application>  

I have palettes for:

• Colors
• Assets
• Effects
• Layout

Works with Flex 3 and 4.