R – Dispatch an event from a class that inherits from EventDispatcher

actionscript-3apache-flexflash

I've got a class that extends EventDispatcher.

What I want to do is to dispatch the click event when the component is clicked. (The class is essentially some text in a textfield that needs to be able to do certain things, and it needs to be able to respond to a click). Sounds easy enough… I want the event dispatched when that portion of the text is clicked. But uh…how? it's not like a button where I can just go

myButton.addEventListener(MouseEvent.CLICK, myClickHandler);

That's clear, because some component is going to be listening for the Click event dispatched when myButton is clicked. It is built into the AS3 framework that a button knows how to listen for a click event.

After the import statements I've got:

[Event(name="click" type="mx.events.Event")]

How do I dispatch the event when the component is clicked, when the component doesn't yet know how to respond to a click event? I've tried adding an event listener in the textfield which contains this custom class of text, but nothing's happening because the Click event hasn't been dispatched.

Best Answer

You can create your own click event and dispatch it. You can do that also to dispatch clicks on objects where no user ever have clicked :D

Try this:

var mEvent:MouseEvent = new MouseEvent(MouseEvent.CLICK, [HERE MORE PARAMS BY YOU]);
yourObject.dispatchEvent(mEvent);

Now, you will recieve Click Events from yourObject.

Related Solutions

Flex AS3 – Dispatch Event to all instances of ItemRenderer

If your custom ItemRenderer instances have access to the List instance somehow, it's straigh forward - just register your event handling method:

theList.addEventListener(YourCustomEvent.CUSTOM_EVENT, itemRendererCustomHander);

If you don't have direct access (which I assume), you can still do it indirectly, e.g. through a delegate of the ItemRenderer's class object. Make an instance of a subclass of EventDispatcher a static property of the ItemRenderer class, and in your ItemRenderer constructor, register an event handler with it:

public class ItemRenderer {
    public static var eventDelegate:YourCustomEventDispatcher;

    public function ItemRenderer() {
        eventDelegate.addEventListener(YourCustomEvent.CUSTOM_EVENT, itemRendererCustomHander);
        (...)
    }

    public function itemRendererCustomHander(event:YourCustomEvent) {
        (...)
    }
}

Now, when you create theList (either in ActionScript or in the initialize event handler of your MXML component), make a new YourCustomEventDispatcher, give to it a reference to theList, and add it to ItemRenderer. YourCustomEventDispatcher registers a private event handler for YourCustomEvent with theList, and just redispatches it. Since all ItemRenderer instances have in turn registered for YourCustomEvent with YourCustomEventDispatcher, theLists's YourCustomEvent reaches all ItemRenderers via one hop.

This is basically an implementation of the Observer design pattern.

AS3 Dispatch Custom Event from class to class

You have to make two modifications:

First, set your event bubbles property to true, so when a Country clip dispatches an event it will go up to the top level.

Then your MenuButtons should listen to stage, not to themselves. So when a Country dispatches an event it goes up to stage and can be caught by the buttons. If you want to listen to the stage you have to do a slight change in your code:

public function MenuButton() {

    this.buttonMode = true;
    this.addEventListener(MouseEvent.MOUSE_OVER,onMouseOver);
    this.addEventListener(MouseEvent.MOUSE_OUT, onMouseOut);
    this.addEventListener(Event.ADDED_TO_STAGE, onAddedToStage);
}

private function onAddedToStage(e:Event):void 
{
    removeEventListener(Event.ADDED_TO_STAGE, onAddedToStage);
    stage.addEventListener(CountryEvent.COUNTRY_HOVERED,onCountryOver); 
}

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