Thanks gingermoleman

Thanks a lot. Some performance issues like

for(var i:int=0;i<myArray.length;i++) 

Select all Open in new window

gives me impression that this is dumb AS$ :P

Thanks for your feedback Jakob - much appreciated by all of us I'm sure.
When I first started with AS3 I couldn't figure out how to achieve this and eventually arrived at this solution which worked well for me thus far.  I should have mentioned it's how I do it but not necessarily the best way. Usually in the posts I do that but I was repeating myself so many times that I ended up doing this article.


1. explain #1 to me please
2. the get/set option sounds familiar from my Java days. My OOP knowledge and experience is limited.
3. making data null optional would make this much more generic thus better I agree.
4. why?explain.

Hi Blue-Genie,

The reason why I like the whatever.events namespace structure
is that it matches the one used by flash - making it easier to remember.

import flash.events.Event
import whatever.events.CustomEvent


About the clone and toString overrides:

Event.clone() is used when re-dispatching an event (dispatchEvent(e)). If you don't add
all the properties then the properties of the re-dispatched event won't have the right values
when listeners handle the re-dispatched event. In our case data will be lost.  

An example:
// Add two listeners:
stage.addEventListener(CustomEvent.NOTIFY,firstDispatchHandler,false,0,true)
button.addEventListener(CustomEvent.NOTIFY,secondDispatchHandler,false,0,true)

// Dispatch the CustomEvent on the first                           
stage.dispatchEvent(new CustomEvent(CustomEvent.NOTIFY,{name:"John Doe"}))

private function firstDispatchHandler(e:CustomEvent):void{
    trace("First: "+e.data.name) // traces "John Doe"
    // Re-dispatch event to the second listener
    dispatchEvent(e)
}

private function secondDispatchHandler(e:CustomEvent):void{
    trace("Second: "e.data.name)
    // Without the clone override you'll get an error:
    // TypeError: Error #1034: Type Coercion failed: cannot convert
    // flash.events::Event@54122a01 to whatever.events.CustomEvent.
}



Event.toString() is not required but I find it useful when unsure about what properties is
passed thru the event.

If you don't override Event.toString() tracing your CustomEvent will show:
[Event type="notify" bubbles=false cancelable=true eventPhase=2]

When overriding you'll get this:  
[CustomEvent type="notify" data=[object Object] bubbles=false cancelable=true eventPhase=2]
Now we know that the event is a CustomEvent with a data property  (in this case an object).
 
Tracing events becomes even more useful when dealing with more "advanced" types - like the MouseEvent:
[MouseEvent type="mouseOver" bubbles=true cancelable=false eventPhase=2 localX=38 localY=41 stageX=265.95
stageY=123 relatedObject=null ctrlKey=false altKey=false shiftKey=false buttonDown=false delta=0]
 

Hope it makes sense :)

Best,
Jakob E
 

 

Good article.