ActionScript 3.0 class extends - actionscript-3

Question

SCENARIO:
I have the class characterObject and n class that extends (cat, dog, bird, n...)
public class characterObject
{
public static var totalCounter:int;
}
public class cat extends characterObject
public class dog extends characterObject
public class bird extends characterObject
Is it possible for the extended classes to listen to changes to static variables (eg totalCounter) in the main class with or without events?

Answer 1

This is possible using a combination of getter/setter functions and events.
Getters and Setters, in actionscript, are functions that can be accessed like variables, giving you the ability to execute functions on variable changes.
public class characterObject
{
private static var _totalCounter:int;
protected static var internalDispatcher:EventDispatcher = new EventDispatcher();
public static function get totalCounter():int
{
return _totalCounter;
}
public static function set totalCounter(value:int):void
{
_totalCounter = value;
var event:Event = new Event("totalCounterChanged");
internalDispatcher.dispatchEvent(event);
}
}
As you can see we have a protected static event dispatcher called internalDispatcher, we can listen to events from this object only if we have extended the characterObject class. By hiding the true totalCounter behind the getter/setter we can dispatch an event whenever something changes it's value.
We can then listen for this event in our extended classes:
public class cat extends characterObject
{
public function cat()
{
super();
internalDispatcher.addEventListener("totalCounterChanged",totalChangedHandler);
}
public function totalChangedHandler(event:Event):void
{
//Your code here;
}
}
Depending on your requirements it maybe better to have your Event Handlers be static also to reduce the same code being executed multiple times without a change in output.