Removing a MovieClip places on the .fla Stage

programming flash
1

Ok, this is a weird issue. I have several MovieClips all linked to a class in a separate .as file (as I think is appropriate)

Now, on a certain event (KEY_DOWN in this case) I want to replace one movie clip with another, which seemed pretty easy. Add the new object, move it to the correct place, then erase the current object.

Apparently it’s not. If the MovieClip is added to the stage, when I call

this.parent.removeChild(this)

, the MovieClip gets removed, then it reappears.

It also seems like it’s calling the event handler function twice, based on the output of trace().

I also get another error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
    at FullPipeW/rotateLeft()
    at FullPipe/keyboard_handler()

If I added the MovieClip via ActionScript (instead of dragging from the Library onto the Flash stage) The Clip gets removed from the screen, but I still get the error above the 2nd time I trigger the event.

Code:


//This line is in the constructor
stage.addEventListener(KeyboardEvent.KEY_UP, keyboard_handler);



        public function keyboard_handler(e:KeyboardEvent):void
        {
            if (isSelected) //variable defined in constructor
            {
                trace(this+":"+this.name+"selected and beginning to rotate");
                if (e.keyCode == Keyboard.LEFT)
                    rotateLeft();
                else if (e.keyCode == Keyboard.RIGHT)
                    rotateRight();
            }
        }

Here’s RotateLeft() (defined in a subclass of the class referenced above)


        public override function rotateLeft()
        {
            var FPN:FullPipeN = new FullPipeN("false"); 
            FPN.x = this.x;
            FPN.y = this.y;
            parent.addChild(FPN);
            
            //These could not have been done in the constructor, since they rely on the fact that the clip is added to the display list.
            FPN.updateWalls(); //adds other movie clips on top of this object
            FPN.addKeyboardListener(); //added the keyboardlistener for the new object

            trace("FPN is "+FPN+":"+FPN.name);
            
            //remove this object
            this.removeWalls(); //undoes updateWalls() also causes some problems i haven't been able to pinpoint
            this.parent.removeChild(this);
        }

I’m using Actionscript 3.0 and Flash CS3.
Thanks in advance!