Dispatching events between different classes

Question

Im trying to dispatch and event from an XML class.
dispatchEvent(new Event (XMLClass.INDEX_CHANGED));
and catch it in the display class
import AS.XMLClass;
private var _xml  = new XMLClass();
_xml.addEventListener(XMLClass.XML_LOADED, swapImage);
I know that im missing something because the application works
and the function runs but its not dispatching the event the event
or maybe it's not catching the event in the display class, even though everything else is working
and im not gettin' any errors.

Answer 1

that's exactly what i did.
i have 3 classes
AS.XMLClass
AS.ControlClass
AS.DisplayClass
It's like a slideshow thing.
I have a button on stage thats connected to the control class and every time you press it
it changes the index of the image in the xmlclass and everytime that the index is changed the xmlclass needs to
dispatch and event that the index has changed and the display class is going to catch the event and change the image
everything is working except the xmlclass dispatch event or the displayclass catch event
XMLCLASS
public static const INDEX_CHANGED:String = "indexChanged";
private function dataLoaded(event:Event):void{
            trace("xml file is loaded");
            data = new XML(loader.data);
            dispatchEvent(new Event(XMLClass.XML_LOADED));
            totalItems = data.images.photo.length();
            setCurrentIndex(currentIndex);
CONTROL CLASS
import AS.XMLClass;
private var _xml = new XMLClass();
public function leftButtonClicked(){
            _xml.setCurrentIndex(_xml.currentIndex = _xml.currentIndex - 1);
        public function rightButtonClicked(){
            _xml.setCurrentIndex(_xml.currentIndex = _xml.currentIndex + 1);
DISPLAY CLASS
import AS.XMLClass;
private var _xml  = new XMLClass();
_xml.addEventListener(XMLClass.XML_LOADED, swapImage);
public function swapImage(event:Event){
            trace("working....");