Actionscript 3, access Symbol properties (AS Linkage) - actionscript-3

Question

I have created a new Symbol in the Flash IDE, I set it to Export for Actionscript and it has a class name of itemCoin
My stage has now 3 movieclips of that class, how can I:
count how many of itemCoin are on the stage
manipulate them, set and get their x, y individually etc. I tried itemCoin[0].x [1] [2]...etc but it throws an error
remove them from stage when needed
add an event listener that executes a function whenever a itemCoin is removed?

Answer 1

Instance name is used for referencing instances of objects.
For example, if you had a symbol of type ItemCoin (note that naming convention for a type usually starts with a capital letter):
When you place instances on the stage, you give them an instance name to reference them by (note that naming convention for an instance is usually camel case):
Now, properties may be accessed by referencing the instance name from code:
itemCoin1.x = 50;
itemCoin1.y = 25;
Remove it form stage:
removeChild(itemCoin1);
Add an event listener to the itemCoin1 instance for when it is removed:
import flash.events.Event;
itemCoin1.addEventListener(Event.REMOVED, removedHandler);
function removedHandler(event:Event):void {
trace("itemCoin1 was removed");
}
removeChild(itemCoin1);
Although generally a poor practice, you can iterate all children to identify instances. For example, to count the number of ItemCoins:
import flash.display.DisplayObject;
var count:uint = 0;
for (var i:uint = 0; i < numChildren; i++) {
var obj:DisplayObject = getChildAt(i);
if (obj is ItemCoin) {
trace("Found " + ++count + " item coins so far.");
}
}
To comprehensively search the display list, you'd have to traverse children of all display objects.
If knowing the total number of instances on the stage was that important, it might be a better idea to define some ActionScript inside the component or within a Factory class to reference count when added to stage and removed from stage.