Question

Good Evening,

I can’t seem to get my code to only add one instance of an object to the stage. It seems to add atleast 3 instances of the object to the stage. The objects added is r2, r3 and r4.

stop();

import flash.events.Event;
stage.focus=stage;
var upKeyDown5:Boolean = false;
var rightKeyDown5:Boolean = false;
var downKeyDown5:Boolean = false;
var leftKeyDown5:Boolean = false;
var enterkey:Boolean = false;
var interaction:Boolean = false;
p5.addEventListener(Event.ENTER_FRAME, moveChar5);
stage.addEventListener(KeyboardEvent.KEY_DOWN, checkKeysDown5);
stage.addEventListener(KeyboardEvent.KEY_UP, checkKeysUp5);
Mouse.hide();
function moveChar5(e:Event):void{
if(downKeyDown5 && !upKeyDown5 && !rightKeyDown5 && !leftKeyDown5)
{
    p5.gotoAndStop("walk_down");
    if(p5.y < 492.75)
        p5.y += 6;
}
if(upKeyDown5 && !downKeyDown5 && !rightKeyDown5 && !leftKeyDown5)
{
    p5.gotoAndStop("walk_up");
    if(p5.y > 202.85)
        p5.y -= 6;
}
if(rightKeyDown5 && !upKeyDown5 && !downKeyDown5 && !leftKeyDown5)
{
    p5.gotoAndStop("walk_right");
    if(p5.x < 871.5)
        p5.x += 6;
}
if(leftKeyDown5 && !upKeyDown5 && !rightKeyDown5 && !downKeyDown5)
{
    p5.gotoAndStop("walk_left");
    if(p5.x > 203.65)
        p5.x -= 6;
}
if(enterkey && interaction && p5.hitTestObject(c1)){
    if (!(Boolean(stage.getChildByName('r2')))) {
        var rat2:r2;
        rat2 = new r2();
        addChild(rat2);
        rat2.y=38;
        rat2.x=32;
    }
}
if(enterkey && interaction && p5.hitTestObject(c2)){
    if (!(Boolean(stage.getChildByName('r3')))) {
        var rat3:r3;
        rat3 = new r3();
        addChild(rat3);
        rat3.y=38;
        rat3.x=32;
    }
}
if(enterkey && interaction && p5.hitTestObject(c3)){
    if (!(Boolean(stage.getChildByName('r4')))) {
        var rat4:r4;
        rat4 = new r4();
        addChild(rat4);
        rat4.y=38;
        rat4.x=32;
    }
}
 }


 function checkKeysDown5(event:KeyboardEvent):void{
if(event.keyCode == 87){
    upKeyDown5 = true;
}
if(event.keyCode == 68){
    rightKeyDown5 = true;
}
if(event.keyCode == 83){
    downKeyDown5 = true;
}
if(event.keyCode == 65){
    leftKeyDown5 = true;
}
if (event.keyCode == 13){
    enterkey = true;
}
 }


 function checkKeysUp5(event:KeyboardEvent):void{
if(event.keyCode == 87){
    upKeyDown5 = false;
    p5.gotoAndStop("still_up");
}

if(event.keyCode == 68){
    rightKeyDown5 = false;
    p5.gotoAndStop("still_right");
}

if(event.keyCode == 65){
    leftKeyDown5 = false;
    p5.gotoAndStop("still_left");
}

if(event.keyCode == 83){
    downKeyDown5 = false;
    p5.gotoAndStop("still_down");
}

if (event.keyCode == 13){
    enterkey = false;
}

if(p5.hitTestObject(c1) || p5.hitTestObject(c2) || p5.hitTestObject(c3)){
    p5.gotoAndStop("interaction");
    interaction = true;
}
else
    interaction = false;
 }

Thanks in advance

Answer 1

It would be more efficient and cleaner to use a switch statement instead all those if statements (if you only ever want one and only one of those conditions to be met)

You’re issue I think has to do with the way you’re tracking your rats – eg. using the stage.getChildByName.
Below is an example, plus some commented notes on some of your other potential issues.

switch(true){
    case (enterkey && interaction && p5.hitTestObject(c1)):
        if (!(Boolean(stage.getChildByName('r2')))) {  //your not giving your rat a name so this will always return false, plus you're not adding the rat to the stage but to this class
            var rat2:r2;
            rat2 = new r2();
            addChild(rat2); //use stage.addChild if you want the above check (stage.getChildByName) to work
            rat2.y=38;
            rat2.x=32;
            rat2.name = "r2"; //if you want the above check to work

            break;  //break out of the switch if you don't want any of the others evaluate since this rat got added
        }

    //do a case for your other blocks
}

It would be better to not use stage.getChidByName at all, and instead create a method like this:

function checkRatExists(ratClass:Class):Boolean {
    var tmp:DisplayObject;
    var i:int = numChildren;
    while(i--){
        tmp = getChildAt(i);
        if(tmp is ratClass){
            return true;
        }
    }
    return false;
}

Then use that new function instead of stage.getChildByName:

if (!checkRatExists(r2)) //r2 is the class of rat you want to check

---

As an aside from your issue, it would be much cleaner to create a method/function to do your rat positioning and adding instead of duplicated the code over and over and over…

function addRat(rat:RatCommonBaseClass, ratName:String):void {
        addChild(rat);
        rat.y=38;
        rat.x=32;
        rat.name = ratName;
}

//now you can just do this for all your rats:
addRat(new r2(),"r2);