This Keyword

[jimfid45]

Hello,

I found this code for a preloader. The part I never get is the usage of the this keyword.

stop();

this.addEventListener(Event.ENTER_FRAME, loading);

function loading(e:Event):void{

var total:Number = this.stage.loaderInfo.bytesTotal;
var loaded:Number = this.stage.loaderInfo.bytesLoaded;

bar_mc.scaleX = loaded/total;
loader_txt.text = Math.floor((loaded/total)*100)+ "%";

if (total == loaded){
play();
this.removeEventListener(Event.ENTER_FRAME, loading);
}

}

Where ir says:

var total:Number = this.stage.loaderInfo.bytesTotal;

Is it suggesting this stage  ? Meaning is there some other stage? Is the this keyword even needed?

Thanks,

Jim

[AttaBoy2]

It's usually not needed.

[Guest]

AttaBoy is right, this is rarely needed anymore with AS3. The only time I have used it recently is when I need to use bracket notation to be able to iterate a sequence like:

this["image" + i].x = ...

That being said, you can simply remove this from your code sample and it'll be fine. And to be clear - this refers to the current timeline.. but you're 'in' the current timeline... so no need for 'this'.

[rob day]

When you write a class this can be useful if you want to make a function parameter available to the entire class. Something like below where this.w=w makes the w var available to the entire class.

package{

import flash.display.Sprite;

public class ClassName extends Sprite {

private var w:Number;

private var h:Number;

//- CONSTRUCTOR --------------------------------------

public function ClassName(w:Number, h:Number) {

this.w=w;

this.h=h;

}

//- PUBLIC METHODS ------------------------------------

public function myFunction():void {

trace(w, h);

}

}

}

[Guest]

This is still not needed - it's easier to use $:

public function ClassName($w:Number, $h:Number) {

w = $w;

h = $h;

}