Eventlisteners Not Working On Main Sprite AS3 - actionscript-3

Question

I have been looking around at a few articles and SO questions to get a grasp on what exactly I am experiencing with my project, but have not found an answer.
I am creating a main sprite that acts as my root for this particular project (I am using terminology as I currently understand it. If I am in error please correct me). In that sprite class, I add a MouseEvent listener so that I can operate in some way with the mouse. The problem is, the main sprite acts as if it either can not read my mouse events or it has no size and therefore can not register mouse events. Here are my classes and the tests I have preformed.
============
Main Class =
============
package
{
import flash.display.Sprite;
import Fu;
[SWF(backgroundColor = "0xffffff", width = "550", height = "400")]
public class Main extends Fu
{
public function Main():void
{
super();
addMouseListener();
}
}
}
==========
Fu Class =
==========
package
{
import flash.display.Sprite;
import flash.events.Event;
import flash.events.MouseEvent;
public class Fu extends Sprite
{
private var display_height:uint;
private var display_width:uint;
private var default_background_color:uint;
public function Fu(display_height:uint = 400, display_width:uint = 550, default_background_color:uint = 0x2e2e2e)
{
this.display_height = display_height;
this.display_width = display_width;
this.default_background_color = default_background_color;
if (stage) {
init();
}
else {
addEventListener(Event.ADDED_TO_STAGE, init);
}
}
private function init(e:Event = null):void {
removeEventListener(Event.ADDED_TO_STAGE, init);
graphics.beginFill(default_background_color, 1);
graphics.drawRect(0, 0, display_width, display_height);
}
public function addMouseListener():void {
trace("Added Mouse Listeners");
addEventListener(MouseEvent.CLICK, onMouseEvent);
// Also tried MouseEvent.MOUSE_OVER, MouseEvent.ROLL_OVER
// with no results either.
}
private function onMouseEvent(e:Event):void {
trace("Mouse Event Fired.");
}
}
}
Everything compiles ok and runs just fine until I try to activate a MouseEvent such as a click, in which case, nothing is output to the console.
================
Console Output =
================
Added Mouse Listeners
//Event messages should appear here...
If I then add a second sprite (s) to the Main class with the following code...
===========================
Added to Main constructor =
===========================
var s:Sprite = new Sprite();
s.name = "s";
s.graphics.beginFill(0x000000);
s.graphics.drawRect(0, 0, 200, 200);
addChild(s);
and click on s I get the "Mouse Event Fired." in the console window, but not when I click outside of s' 200x200 box.
I also tried adding the listener to the stage (which is not ideally what I want since I want these listeners to only affect the main sprite of this specific SWF file) and tracing out...
trace(e.target, " ", (e.target as DisplayObject).name);
The areas not covered by sprite s display "[object Stage] null" in the console and "[object Sprite] s" is displayed when s is clicked.
An obvious fix would be to use s as my "stage" and call it a day, but I an curious why event listeners do not work on the main sprite and why it does not have a default instance name like other sprites do.
Any ideas?

Answer 1

You document class cannot extend Fu since Fu require two parameters and a document class cannot have one. Besides it makes no sense for a document class to extend anything other than Sprite or MovieClip since there cannot be any object higher in the hierarchy of your app. But if you have to extend a custom super class that super class cannot take parameter. Instead create a separate init method that you call explicitly yourself to register your events and draw your content.
Document classes are a special case. When used as the main entry in your app (as opposed to an externally loaded swf), they are set to not receive interactive event directly and behave much like a Singleton. They are also set as the root of your app and are the only DisplayObject that has the stage directly available in constructor. The design idea is that it should be a container for your app and not a part of it directly. The hierarchy is stage -> root (document class) -> your app elements.
In your case for example if you were to add a Fu instance as a child of the document class instance then it will receive mouseevent normally and the document class would also catch those event as they propagate.