[RESOLVED] Dispatch and Listen for a Global Event

[5TonsOfFlax]

The built in event system does not include a "broadcast" functionality. But you can pretty easily build one yourself by making a single instance to dispatch your events.

public class Broadcaster extends EventDispatcher {
  private var _instance:Broadcaster = null;

  //DO NOT USE THIS.  Use static methods broadcastEvent and addBroadcastListener instead
  public function Broadcaster(){
    if (_instance != null){
       throw new IllegalOperationError("Broadcaster constructor called more than once");
    }
  }

  private static getInstance():Broadcaster{
    if (null == _instance){
       _instance = new Broadcaster();
    }
    return _instance;
  }

  public static broadcastEvent(event:Event):void{
    getInstance().dispatchEvent(event);
  }

  public static addBroadcastListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void{
    getInstance().addEventListener(type, listener, useCapture, priority, useWeakReference);
  }

}

Then you can register a listener from anywhere:

Broadcaster.addBroadcastListener("someEvent", somehandler);

And trigger dispatch from anywhere

Broadcaster.broadcastEvent(new Event("someEvent"));

[badaboom55]

dispatchEvent(new Event("DispatcherClassEvent", true));

addEventListener("DispatcherClassEvent", doThisFunction);

function doThisFunction(evt:Event):void {
     trace("Woo Hoo");
}

Just changing "bubbles" to true doesn't seem to work. At least not with objects outside of the dispatcher's display list hierarchy. Using the above I could "hear" the event in the dispatcher's parents... but not in the dispatcher's 3rd cousins twice removed.

The built in event system does not include a "broadcast" functionality. But you can pretty easily build one yourself by making a single instance to dispatch your events.

Thanks, I've used classes like that with static functions before, don't know why it didn't occur to me to make a Broadcaster like that. Mainly I've used them to store utility functions that I use frequently, like truncating text, or generating random numbers, etc. The chief benefit, for me, was that instead of something like:

var myUtilFunctions:UtilFunctions = new UtilFunctions();
myUtilFunctions.someFunction();

I could just:

UtilFunctions.someFunction();

In fact, you essentially tell me the same by noting "//DO NOT USE THIS." in regards to the constructor.
but, there are a couple of nuances in your code I don't quite understand.

1) I'm used to seeing the word "function" after "static", is that a typo? Or are getInstance(), broadcastEvent() and addBroadcastListener() not what I know as methods?

2) What is the benefit/purpose to the getInstance() method? The Broadcaster class could be used "instance-less" couldn't it? Why use one of these over the other:

public static broadcastEvent(event:Event):void{
    getInstance().dispatchEvent(event);
}

public static broadcastEvent(event:Event):void{
    dispatchEvent(event);
}

ps. Those utility classes I had created before never extended anything... since they really had no higher functionality than as a storage area for functions. So does extending an actual class (i.e. EventDispatcher) needs to be handled differently?