how to remove listener

[trinoo]

Hello guys, a noob question here:

if I set up listeners like this, all works fine for me:

myobject.on("pointerdown", onPointerDown);

function onPointerDown(ev){
     	myobject.on("pointermove", onPointerMove);
     	myobject.on("pointerup", onPointerUp);     	
}

function onPointerMove(ev){
	//do some things
}

function onPointerUp(ev){
	myobject.off("pointermove", onPointerMove);
}

but if I set up things like this:

myobject.on("pointerdown", onPointerDown);

function onPointerDown(ev){
	var a = somevalue;
        var b = somevalue;
     	myobject.on("pointermove", onPointerMove.bind(this, a, b));//closure here to pass aditional parameters to callback
     	myobject.on("pointerup", onPointerUp);     	
}

function onPointerMove(param_a,param_b,ev){
	//do stuff with param_a,param_b and ev here
}

function onPointerUp(ev){
	myobject.off("pointermove", onPointerMove);//does not work
	myobject.off("pointermove", onPointerMove.bind(this, a, b));//also does not work
	myobject.removeAllListeners();//works, but this is not, what I need
}

If I make a closure callback, I'm not able to remove onPointerMove listener then. Can anybody explain me, what is going on there or what am I missing?

(new to Pixi and JavaScript in overal, so sorry if too stupid question...)

thanks

[ivan.popelyshev]

You have to store that "onPointerMove.bind(this, a, b)" somewhere, and pass it to "off" later.

[trinoo]

Thanks for answer, but Im not sure, if I understand you right.

Its like a kind of dragging:

on-pointer-down (start drag) --> sets listeners for on-pointer-move (moving objects) and on-pointer-up (stop moving)--> when on-pointer-up, then  stop dragging/moving  - so I need to remove on-pointer-move listener right when on-pointer-up event occurs. How can I store it and use later?

And also, how its possible, that removeAllListeners() works? I was trying to find this method in Pixi sources to study it, but cannot find its definition anywhere...

Seems like I have to use standard approach without closure and pass those two needed arguments differently...but just interested in...

 

[ivan.popelyshev]

var stuff = onPointerMove.bind(this, a, b)

obj.on('pointermove', stuff);
obj.off('pointermove', stuff);

 

[botmaster]

using 'bind' creates a copy of the method (it's a totally different object!) so when you remove that listener after using the original method it can't work since you registered a copy of that method instead. So if you use 'bind' you need to keep a reference of that copy in order to remove it later.

[trinoo]

Thanks guys, understand it now.