R – Base class for custom components

I did a simple bootstrap similar to Borek (see below). I would love to get rid of the mxml file, but if I don't have it, I don't get any of the standard themes that come with Flex (haloclassic.swc, etc). Does anybody know how to do what Theo suggests and still have the standard themes applied?

Here's my simplified bootstrapping method:

main.mxml

<?xml version="1.0" encoding="utf-8"?>
<custom:ApplicationClass xmlns:custom="components.*"/>

ApplicationClass.as

package components {
    import mx.core.Application;
    import mx.events.FlexEvent;
    import flash.events.MouseEvent;
    import mx.controls.Alert;
    import mx.controls.Button;

    public class ApplicationClass extends Application {
        public function ApplicationClass () {
            addEventListener (FlexEvent.CREATION_COMPLETE, handleComplete);
        }
        private function handleComplete( event : FlexEvent ) : void {
            var button : Button = new Button();
            button.label = "My favorite button";
            button.styleName="halo"
            button.addEventListener(MouseEvent.CLICK, handleClick);
            addChild( button );
        }
        private function handleClick(e:MouseEvent):void {
            Alert.show("You clicked on the button!", "Clickity");
        }
    }
}

Here are the necessary updates to use it with Flex 4:

main.mxml

<?xml version="1.0" encoding="utf-8"?>
<local:MyApplication xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:local="components.*" />

MyApplication.as

package components {
    import flash.events.MouseEvent;
    import mx.controls.Alert;
    import mx.events.FlexEvent;
    import spark.components.Application;
    import spark.components.Button;

    public class MyApplication extends Application {
        public function MyApplication() {
              addEventListener(FlexEvent.CREATION_COMPLETE, creationHandler);
        }
        private function creationHandler(e:FlexEvent):void {
            var button : Button = new Button();
            button.label = "My favorite button";
            button.styleName="halo"
            button.addEventListener(MouseEvent.CLICK, handleClick);
            addElement( button );
        }
        private function handleClick(e:MouseEvent):void {
            Alert.show("You clicked it!", "Clickity!");
        }
    }
}

You are correct, they don't work, never have all the way back the the Flex Builder 2 betas.

This was actually the topic of my first blog post ever. It has a hacky workaround that kind works if you're interested, but it's a bit long to post here:

http://www.rogue-development.com/blog2/2007/03/code-in-front/