<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/03/29/dynamically-loading-xml-files-using-the-httpservice-tag/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white" viewSourceURL="srcview/index.html">

    <mx:Script>
        <![CDATA[
            import mx.rpc.events.ResultEvent;
            import mx.rpc.events.FaultEvent;
            import mx.controls.Alert;

            private var alert:Alert;

            private function loadGallery(src:String):void {
                httpService.url = src;
                httpService.send();
            }

            private function httpService_fault(evt:FaultEvent):void {
                var title:String = evt.type + " (" + evt.fault.faultCode + ")";
                var text:String = evt.fault.faultString;
                alert = Alert.show(text, title);
                xmlListColl.removeAll();
            }

            private function httpService_result(evt:ResultEvent):void {
                var xmlList:XMLList = XML(evt.result).images.image;
                xmlListColl = new XMLListCollection(xmlList);
            }
        ]]>
    </mx:Script>

    <mx:XMLListCollection id="xmlListColl" />

    <mx:HTTPService id="httpService"
            resultFormat="e4x"
            fault="httpService_fault(event);"
            result="httpService_result(event)" />

    <mx:ApplicationControlBar dock="true">
        <mx:Button label="gallery 1"
                click="loadGallery('gallery1.xml');" />
        <mx:Button label="gallery 2"
                click="loadGallery('gallery2.xml');" />

        <mx:Button label="gallery 404"
                click="loadGallery('gallery404.xml');" />
    </mx:ApplicationControlBar>

    <mx:TileList id="tileList"
            dataProvider="{xmlListColl}"
            itemRenderer="TileListItemRenderer"
            columnCount="3"
            columnWidth="150"
            rowCount="2"
            rowHeight="100" />

</mx:Application>