Load SWF and override existing library symbols

Question

I have Main.fla and SkinA.fla. Both have MovieClip library item: MC_BrandLogo.
I'm loading the SkinA.swf into Main.swf in the current application domain trying to replace the class inside Main.swf. If there is no library item in the Main.fla, I can instantiate MC_BrandLogo with the correct graphic. If the MC_BrandLogo already exist in the Main.fla then that graphic is used even though I loaded new one in the current application domain.

Is there a way to replace existing linked movie clips with loaded dynamically?

var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, onSkinLoaded);
var context:LoaderContext = new LoaderContext(false, ApplicationDomain.currentDomain);
loader.load(new URLRequest("SkinA.swf"));

function onSkinLoaded(e:Event):void {
    trace("loaded Skin");
    addChild(new MC_BrandLogo());
}

EDITED: There is no way to override the images I was trying to override, because this is how application domains work. If the definitions exist in the parent application domain, they are used.

Answer 1

As far as I know you can not overwrite a Class Definition in an ApplicationDomain unless you wish to resort to manipulating bytecode at runtime.

What you can do, however, is load your skin SWF into a child Application Domain and then retrieve the appropriate Class Definition (symbol) via ApplicationDomain.getDefinition; ie:

private var _skinAppDomain : ApplicationDomain;

function loadSkin() : void {
    // Keep a reference to the Skin's application domain.
    _skinAppDomain = new ApplicationDomain();

    var loader:Loader = new Loader();
    var context:LoaderContext = new LoaderContext(false, _skinAppDomain);

    loader.contentLoaderInfo.addEventListener(Event.COMPLETE, onSkinLoaded);
    loader.load(new URLRequest("SkinA.swf"));
}

function onSkinLoaded(e:Event) : void {
    var brandLogoSymbolName : String = "MC_BrandLogo";

    // Retrieve the symbol from the Skin's Application Domain directly.
    var brandLogoClipClazz : Class = _skinAppDomain.getDefinition(brandLogoSymbolName);

    // Check we have the symbol.
    if (brandLogoClipClazz == null) {
        throw new Error("Skin SWF must include a symbol named: " + brandLogoSymbolName);
    }

    addChild(new brandLogoClipClazz());
}

To help debug missing symbol names in ApplicaitonDomains you can list all Class Definitions (symbols) contained by using SWF Explorer.

Answer 2

Beaten to the punch. JonnyReeves is correct I believe. A good discussion on this topic can be found here:

Application Domains on Senocular