Introduction to XML in Flash
       by senocular

Preloaders With XML
Just like anything else loaded into Flash, you can also create preloaders for XML. Generally, however, since XML is usually light on the loading side, preloaders aren't needed. A general "Now Loading" message usually suffices. But sometimes, for those real hefty files, you may want a preloader to show the status of the XML loading.

If you're worried about learning a whole new way of making preloaders for XML, don't be. Making a preloader for XML is exactly like making one for a loaded SWF or JPEG. The only difference is that instead of calling getBytesLoaded and getBytesTotal from a movie clip, you're calling it from your XML instance. So really, you can use preloaders created for movie clips with XML so long as you reference the XML object to get bytes loaded and bytes total. Here's a quick example of a preloader that can work with XML as well as movie clips:

preloadbar_mc.onEnterFrame = function(){

if (!this.target) return (0);

var loaded = target.getBytesLoaded();

var total = target.getBytesTotal();

 

var scale = 0;

if (loaded && total){

var percent = loaded/total;

scale = 100 * percent;

}

 

this._xscale = scale;

}

 

preloadbar_mc.target = my_xml;

Where preloadbar_mc is a horizonally scaling movie clip representing the preloader and my_xml is the XML instance you wish to show the preloader for. The onEnterFrame event of the preloadbar_mc runs the preloader using a generic target to get bytes loaded and bytes total. Whether this is a movie clip or an XML instance, as long as getBytesLoaded and getBytesTotal work, it doesn't matter.