AS3 : EventListener won't be removed in an [IF] - actionscript-3

Question

I have searched how to pass arguments through EventListeners, and I used the method without calling an anonymous function to remove the EventListener later.
The issue is that the EventListener will be removed if out the IF function, but not if it is in the IF function.
How could I do that ?
The code :
function dragShip(m:MouseEvent):void
{
var func:Function = dispositionShip(m.target);
if (isDragging == false)
{
stage.addEventListener(KeyboardEvent.KEY_DOWN, func);
m.target.startDrag(true);
isDragging = true;
}
else
{
stage.removeEventListener(KeyboardEvent.KEY_DOWN, func);
isDragging = false;
placeShip(m.target , mouseX , mouseY , m.target.rotation);
}
// if the EventListener is put here, it gets removed, but not if put just in the else
}
NOTE : dispositionShip()returns a function.
Edit : Here is the following part of the code :
function dispositionShip(shipTarg):Function
{
return function(k:KeyboardEvent):void
{
rotateShip(k,shipTarg);
};
}
function rotateShip(k:KeyboardEvent,ship:Object):void
{
if (k.keyCode == 39)
{
ship.rotation += 90;
}
else if (k.keyCode == 37)
{
ship.rotation -= 90;
}
}
Moreover, if I replace rotateShip(k,shipTarg); by a simple trace, it also does not work.

Answer 1

Everytime you call
function dispositionShip(shipTarg):Function
{
return function(k:KeyboardEvent):void
{
rotateShip(k,shipTarg);
};
}
You're creating a new anonymous Object of type Function that calls rotateShip(), so when you call stage.removeEventListener(KeyboardEvent.KEY_DOWN, func); your func is a different Object to the func you passed into addEventListener(), so it doesn't match the orginal listener and doesn't get removed.
A better way to do this would be to store the current mouse target in a member var. IE:
var currentShip:Object;
function dragShip(m:MouseEvent):void
{
if (isDragging == false)
{
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPress);
m.target.startDrag(true);
isDragging = true;
currentShip = m.target;
}
else
{
stage.removeEventListener(KeyboardEvent.KEY_DOWN, keyPress);
isDragging = false;
placeShip(m.target , mouseX , mouseY , m.target.rotation);
currentShip = null;
}
}
function keyPress(k:KeyboardEvent):void
{
rotateShip(k,currentShip);
}