listening to events down the display list in children components

问题

I'm creating a swf, that has a parent class and a child class. The parent class has a button, that dispatches a custom event and I want the child class to list for this event, but when I dispatch the event the child class does not hear the event has been dispatched.

This is the code that dispatches the event:

private function onCTAClicked(e:MouseEvent):void
        {
            trace("onCTAClicked");
            dispatchEvent(new CTAClickEvent(CTAClickEvent.CTA_CLICK_EVENT,true));
        }

And the listener is registered like this:

public function registerEventListeners():void
        {
            this.addEventListener(CTAClickEvent.CTA_CLICK_EVENT, onCTAClickHandler,false);  
        }

The registerEventListeners() function is in the child class.

I know events can bubble up the display list but how can then go down the list?

Stephen

回答1:

No, events do not dig down. They only bubble up. In order for a child of a display object to hear an event dispatched by a parent, in the class of the child object you'll need to add a listener to a reference of the parent object.

public function registerEventListeners() : void {
    parent.addEventListener(CTAClickEvent.CTA_CLICK_EVENT, onCTAClickHandler);
}

Just be sure not to invoke registerEventListeners when parent might be null.

来源：https://stackoverflow.com/questions/6495037/listening-to-events-down-the-display-list-in-children-components