Variable with Multiple Values

[A.Russell]

I want to use a variable across the scope of a class. How do I do this without it having different values in different methods? 

 

Why can a variable declared at class level have a different value depending on the method?: 

 

class variableProblem extends Phaser.Sprite{isMoving: boolean = false;//some code hereeventDragStart() {            this.isMoving = true; <-- sets isMoving to true, though it is undefined on first run (should be false first run)        }update() {            if (this.isMoving) {    <-- isMoving is always false!                 this.bringToTop();                this.isMoving = false;            }}

isMoving has a different value in eventDragStart() to update(). This shouldn't be possible, so I guess it has something to do with the way it compiles to Javascript. 

 

However, I really need only one instance of isMoving in this class, and it is very frustrating. How do I make this work? 

[ZoomBox]

What about adding "var" in front of your isMoving variable.

 

Edit: Yep, sorry, didn't noticed it was typescript code.

 

Edit²: And I completly misread your post, my answer was stupid.

[XekeDeath]

What is "this" in the eventDragStart function..? Given that it is the one not matching the other variables, I am inclined to think that "this" in that function is not the "this" that you think it is...

[A.Russell]

Zoombox: adding var in front makes a syntax error. I am coding in Typescript.

 

XekeDeath: I thought of that, though I can't see what else "this" could be other than the same instance of this object. The event is declared as:

 

this.events.onDragStart.add(this.eventDragStart);

 

I even tried creating getter and setter methods. Though if I try to call them from within eventDragStart, I get an error at runtime. It's as if the callback functions don't exist in the same class.

 

setIsMoving(val: boolean) {

            this.isMoving = val;

        }

 

        getIsMoving(): boolean{

            return this.isMoving;

        }

 

        eventDragStart() {

            this.setIsMoving(true);  <-- JavaScript runtime error: Object doesn't support property or method 'setIsMoving'

        }

 

I additionally specified  isMoving to be private. Fiurthermore, I checked the super class, and it doesn't have a variable called isMoving that it might be conflicting with. 

 

So, I' stumped. Any other ideas?

[XekeDeath]

Yup, take a closer look at onDragStart... It is a Phaser.Signal, and you are calling the add() function on it...

That takes 2 arguments: The function to call, and the context to call it on...

You are only supplying the function to call, try adding "this" as a second argument, and see how things work...

this.events.onDragStart.add(this.eventDragStart, this);

[A.Russell]

Thanks again Xekedeath! You're a legend. 

 

I was following the beginner tutorial at GameFromScratch, which didn't use a second argument.