How to remove all Objects in For Loop?

Question

Hey Everyone So I know this has to be really Simple I am over complicating it and can't figure out how to do it. So I have these stars moving in the background in my startScreen and I want to remove them when the Game starts.

Here is How I have them setup in my Main Class:

             public  var numStars:int = 4;

            //Add star background to startscreen only 
            for (var i:int = 0; i < numStars; i++)
            {
                stage.addChild(new mcStar(stage));
            }

and in my mcStarClass I have this code:

public class mcStar extends MovieClip 
{

    private var stageRef:Stage;
    private var starSpeed:Number;


    public function mcStar(stageRef:Stage)
    {
        this.stageRef = stageRef;
        setupStar(true);

        addEventListener(Event.ENTER_FRAME, loop, false, 0, true); 
    }


    public function setupStar(randomizeY:Boolean = false) : void
    {
        //Pick the frames for start position
        var nRandom:Number = randomNumber(1, 3);
        //Setup goto and stop on timeline
        this.gotoAndStop(nRandom);

        //inline conditional, looks complicated but it's not.
        y = randomizeY? Math.random()*stageRef.stageHeight : 480;
        x = Math.random()*stageRef.stageWidth;
        alpha = Math.random();
        //rotation = Math.random()*360;
        //scaleX = Math.random();
        //scaleY = Math.random();


        starSpeed = 2 + Math.random()*2;
    }

    public function loop(e:Event) : void
    {
         y -= starSpeed;

        if (y <= stage.stageHeight / 2)
            setupStar();

    }

    public function destroyStar():void
    {
        if (this.parent)
        {
            parent.removeChild(this);
            removeEventListener(Event.ENTER_FRAME, setupStar);
            removeEventListener(Event.ENTER_FRAME, loop);
        }

    }

    //Generates a truly "random" number
    function randomNumber(low:Number=0, high:Number=1):Number
    {
      return Math.floor(Math.random() * (1+high-low)) + low;
    }


}

So what I am trying to accomplish is in my Main class when the user presses start and I remove the startScreen I want all the starts to be removed and stop spawning. But I can't figure out How I would go about removing them. When I try I always get a must be a child of the caller, etc...

any help would be appreciated thanks!

Can you post the code you're using in your Main class to remove the stars? — jdfinch3
– jdfinch3, Commented Jun 21, 2015 at 7:17

Andre Lehnert · Accepted Answer · 2015-06-21 08:48:40Z

2

Store the stars in an array when you add it. So you can refer to them later.

The destroyStar-function is not best practice, because the star itself should not have the rights to change something in your main-displaylist. Better remove it directly in Main.

Main

public  var numStars:int = 4;
private var stars:Array = [];

initStars();

function initStars():void{
    for (var i:int = 0; i < numStars; i++)
    {
        var star:mcStar = new mcStar(stage);
        addChild(star);
        stars.push(star);
    }
}
function removeAllStars():void{
    for each(var star:mcStar in stars){
       if(contains(star)) {
           star.destroy();
           removeChild(star);
       }
    stars=[];
}

mcStar

 //better name for this class would be McStar for better readability
 public function destroyStar():void
 {
      removeEventListener(Event.ENTER_FRAME, setupStar);
      removeEventListener(Event.ENTER_FRAME, loop);
 }

Further you dont need to pass the stage to the constructor. If a mcStar-instance is added on stage you can refer the stage (only ONE stage is existing) with this.stage

Greetings.

edited Jun 21, 2015 at 8:48

answered Jun 21, 2015 at 8:40

Andre Lehnert

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2 Comments

null Over a year ago

+1; also, a rule of thumb as a reference from the docs: objects should not be added to the Stage, directly, at all.

Nathan Over a year ago

Hey thanks a lot for this. I really appreciate it. I knew I had to keep it collected in an Array but wasn't quit sure how. Thanks for all the advice Ill def take it into consideration.

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