Broadcast Custom Event from Model - actionscript-3

Question

`My "Model" is an AS class that extends EventDispatcher:
MeetingInfoModel extends EventDispatcher
In this class I broadcast a custom event:
var eventObj:CustomEvent = new CustomEvent( CustomEvent.UPDATE_DOC_COUNTER );
dispatchEvent( eventObj );
I include a metadata tag at top of class:
[Event(name="updateDocCounter", type="com.fmr.transporter.events.CustomEvent")]
I attempt to listen to for this event in an MXML component:
this.addEventListener( CustomEvent.UPDATE_DOC_COUNTER, onDocUpdate );
But it never reaches this listener.
I've run into issues like this a lot and I think there's a crucial part of the Event process that I'm just not understanding.
Can anyone provide any helpful clues, please?
Thank you!
UPDATE:
In response to all the comments below (thank you for all the responses!):
MeetingInfoModel is not a display component and shouldn't be responsible for broadcasting events; that's the piece I was not getting!!
Here's my code: In the MeetingInfoModel constructor I listen for the collection change event of one of its class members:
docsAndAttachmentsList.addEventListener( CollectionEvent.COLLECTION_CHANGE, updateDocsCounter );
In that handler I try to broadcast an event that an MXML component (that is part of the display hierarchy) will handle:
private function updateDocsCounter( event:CollectionEvent ):void
{
var eventObj:CustomEvent = new CustomEvent( CustomEvent.UPDATE_DOC_COUNTER );
dispatchEvent( eventObj );
}
Back in the MXML component, I call this method from the creationComplete handler:
private function addListeners():void{
MeetingInfoModel.getInstance().addEventListener( CustomEvent.UPDATE_DOC_COUNTER, onDocUpdate );
}
It sounds like I should just listen for the collection change event on the MXML component. I tried that but it doesn't work:
MeetingInfo.getInstance().docsAndAttachmentsList.addEventListener( CollectionEvent.COLLECTION_CHANGE, updateDocsCounter );
I don't know why that's not working; it seems to be the best solution.
Here's the full MeetingInfoModel class:
[Bindable]
[Event(name="updateDocCounter", type="com.fmr.transporter.events.CustomEvent")]
public final class MeetingInfoModel extends EventDispatcher
{
//Universal INFO
public var generalInfo:GeneralInfoModel;
public var meetingVO:MeetingVO = new MeetingVO();
public var meetingId:String;
public var bulletinBoardLiveMembers:ArrayCollection = new ArrayCollection();
public var xmppServices:XMPPServices;
public var declinedParticipantsGroup:ArrayCollection = new ArrayCollection();
public var notJoinedParticipantsGroup:ArrayCollection = new ArrayCollection();
public var conferenceRoomParticipantsGroup:ArrayCollection = new ArrayCollection();
public var otherLocationParticipantsGroup:ArrayCollection = new ArrayCollection();
[Bindable]
public var documentList:ArrayCollection = new ArrayCollection();
[BIndable]
public var newAttachmentList:ArrayCollection = new ArrayCollection();
public var docsAndAttachmentsList:ArrayCollection = new ArrayCollection();
public var bulletinBoardMsgList:ArrayCollection = new ArrayCollection();
private var _participantList:ArrayCollection = new ArrayCollection();
public var dismissedMeetingIDs:Array = [];
public var visibleToastWindows:Array = [];
public function MeetingInfoModel()
{
generalInfo = GeneralInfoModel.getInstance();
xmppServices = XMPPServices.getInstance();
_participantList.addEventListener(CollectionEvent.COLLECTION_CHANGE, allParticipantsChangeHandler);
bulletinBoardLiveMembers.addEventListener(CollectionEvent.COLLECTION_CHANGE, bulletinBoardLiveMembersChangeHandler);
docsAndAttachmentsList.addEventListener( CollectionEvent.COLLECTION_CHANGE, updateDocsCounter );
}
private static var model:MeetingInfoModel = null;
public static function getInstance():MeetingInfoModel
{
if (model == null)
{
model = new MeetingInfoModel();
}
return model;
}
/**
* The handler for the collection change event of the docsAndAttachmentsList collection.
*
* We use it to manually update the counter on the Docs tab.
*/
private function updateDocsCounter( event:CollectionEvent ):void
{
var eventObj:CustomEvent = new CustomEvent( CustomEvent.UPDATE_DOC_COUNTER );
dispatchEvent( eventObj );
}
public function displayToastForThisMeeting(meetingID:Number):Boolean
{
//trace("model::meetingID = " + meetingID);
var doDisplayToast:Boolean = false;
var containsMeetingID:Boolean = false;
//the first one
if(dismissedMeetingIDs.length == 0)
{
//trace("dismissedMeetingIDs.length = 0");
doDisplayToast = true;
dismissedMeetingIDs.push(meetingID);
}
else
{
for(var i:int=0; i < dismissedMeetingIDs.length; i++)
{
//trace("dismissedMeetingIDs[" + i + "] = " + dismissedMeetingIDs[i]);
if(meetingID == dismissedMeetingIDs[i])
{ //this one has already been dismissed
doDisplayToast = false;
containsMeetingID = true;
break;
}
else
{
doDisplayToast = true;
containsMeetingID = false;
}
}
if(containsMeetingID == false)
{
dismissedMeetingIDs.push(meetingID);
}
}
return doDisplayToast;
}
}
Here's some code from my MXML component (whose base class is Group):
import com.fmr.transporter.controller.TransporterController;
import com.fmr.transporter.events.CustomEvent;
import com.fmr.transporter.model.MeetingInfoModel;
import com.fmr.transporter.model.TransporterModel;
import mx.collections.ArrayCollection;
import mx.core.FlexGlobals;
import mx.events.CollectionEvent;
import mx.events.FlexEvent;
private var controller:TransporterController;
[Bindable] public var newAttachmentsList:ArrayCollection;
[Bindable] public var meetingInfo:MeetingInfoModel;
private function complete():void
{
controller = TransporterController.getInstance();
addListeners();
}
/** Add listeners to this class.
*/
private function addListeners():void{
MeetingInfo.getInstance().docsAndAttachmentsList.addEventListener( CollectionEvent.COLLECTION_CHANGE, updateDocsCounter );
}

Answer 1

You extended the event class. By default, flex event don't bubble. You need to modify your CustomEvent class constructor to look like this:
public function CustomEvent(type:String){
super(type, true, true);
}
This will make your event bubble and also cancelable per flex event framework. #The_asMan told you correctly about how to deal with a non bubbling event, but I think you may have accidentally missed the right object. Make it bubble and you will hear it!!

Answer 2

#LondonDrugs_MediaServices, #Flextras, and #The_asMan.
These guys are right; it doesn't appear that the class has to be on the display list in order for the event to be listened for. As long as you have the correct target for the class dispatching the event it should be just fine.
For some reason, though, I've done something really weird and couldn't quite figure it out in the end. The solution was to use binding on the collection I updated in the model in order to update the component I wanted.
Thank you everyone for your very helpful comments.