Keyboard Inputs

[Karzam]

Hi everyone, I'm coding a project and I've got a problem when I try getting keyboard input in a dedicated class. 

 

So this is my Controller class : 

Controller = function() {	// Initialisation clavier 	document.onkeydown = this.onKeyDown;	document.onkeyup = this.onKeyUp;	// Touches 	this.left = false;	this.up = false;	this.down = false;	this.right = false;}// Touche appuyée Controller.prototype.onKeyDown = function(event) {	if (event.keyCode == 37) {		this.left = true;	}	if (event.keyCode == 38) {		this.up = true;	}	if (event.keyCode == 39) {		this.down = true;	}	if (event.keyCode == 40) {		this.right = true;	}}// Touche relâchée Controller.prototype.onKeyUp = function(event) {	if (event.keyCode == 37) {		this.left = false;	}	if (event.keyCode == 38) {		this.up = false;	}	if (event.keyCode == 39) {		this.down = false;	}	if (event.keyCode == 40) {		this.right = false;	}}

... with which I create an occurence during initialization. But when I try to get boolean state in an other class : 

// DéplacementPlayer.prototype.move = function() {     if (controler.left) {        this.posHorizontal -= this.speed;    }}

this isn't working ! When I display the state in the controller class it return 'true' but not in another classes. I'v got no error but only a 'false' displayed (i've tried with console.log but no way). 

 

Thanks for help ! 

[OadT]

You call your onKeyDown/Up functions as methods of the document-object, so the this inside them will refer to the document object (document.left is true, but not controler.left)

 

So simply reply replace line 2 and 3 with:

document.onkeydown = this.onKeyDown.bind(this);document.onkeyup = this.onKeyUp.bind(this);

The bind-method simply ensures this refers to your instance.

I would also recommend to use window.addEventListener, because if you want to use multiple instances of Controller later you get into trouble, because the instances override document.onkeydown

window.addEventListener("keydown", this.onKeyDown.bind(this), false);window.addEventListener("keyup", this.onKeyUp.bind(this), false);

I would recommend to read some articles about "this" in javascript, so you know exactly what this all means In javascript "this" is not defined by declaring a function, but by the way you invoke a function.