AS3 array indexOF

Question

I am working on a game and have trouble with this array. There is all fruits on the stage which is generated from the array fruit. When the appel will hit the basket, we will count them. The melon is not to be counted. How do i find out if the current fruit is an appel or a melon?

var array_fruit:Array = new Array(appel1_mc, appel2_mc, melon_mc);
var appelsOnstage:Array = new Array();
var appelsCollected:Number = 0;


for (var i:int = 0; i<10; i++) {
  var pickappels = array_fruit[int(Math.random()* array_fruit.length)];
  var spel_appels:MovieClip = new pickappels();
  addChild(spel_appels);
  spel_appels.x = (Math.random() * 800) + 100;
  spel_appels.y = Math.random() * -500;
  spel_appels.speed = Math.random() * 10 + 2;
  appelsOnstage.push(spel_appels);

}


stage.addEventListener(Event.ENTER_FRAME, catchappels);

function catchappels(e:Event):void {

for (var i:int = appelsOnstage.length-1; i > -1; i--) { 
    var currentfruit:MovieClip = appelsOnstage[i];


    if (currentfruit.hitTestObject(basket_mc)) {        

        if(array_fruit.indexOf(currentfruit) == melon_mc ){
               trace("melon");
            } else {
               trace("no melon");
               appelsCollected++;
            }
    }
 }
}

I put some more code here. appelsOnstage is an array containing the appels on the stage. — Henrique
– Henrique, Commented Oct 30, 2016 at 15:06

null · Accepted Answer · 2016-10-30 18:34:23Z

1

a_fruit.indexOf(currentfruit) = -1 all the time

The problem here is the confusion between classes and objects.

a_fruit holds classes, which are to be instantiated by this code

var pickappels = array_fruit[int(Math.random()* array_fruit.length)];
var spel_appels:MovieClip = new pickappels();

appelsOnstage holds objects of those classes and is filled here
```
appelsOnstage.push(spel_appels);
```

Classes and objects are - excuse the pun! - apples and oranges, very different things. A class is like a blueprint for a building or a recipe for a meal. You cannot compare objects with classes and expect them to be the same.

Instead, you should find the class of an object, and then compare this class to another class. For this, you use the is operator. Something like

if(currentfruit is melon_mc)

should do the trick to tell you if you have a melon or not.

answered Oct 30, 2016 at 18:34

null

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4 Comments

Henrique Over a year ago

the output showed me indeed [object melon_mc] and [class melon_mc] so I tried the suggestion of curretfruit == melon_mc as well and that gives an error about static.flash.movieclip can not compare with classes.

null Over a year ago

@Henrique I'm not quite sure what you are trying to say. I never suggested to use currentfruit == melon_mc. Is your problem solved with what I suggested in my answer or not? If not what exactly have you tried and what was the exact error you received?

Henrique Over a year ago

Ok, thank you for your help. I will make a different array for the other fruit.

Henrique Over a year ago

I think the problem was indeed the confusion between objects and classes and I made two arrays now, one for the apple's and one for the fruit and that works perfectly.

Neal Davis · Accepted Answer · 2016-10-30 16:33:12Z

0

indexOf is going to return an int value. See my edit to your code below.

if (currentfruit.hitTestObject(basket_mc)) {        
    if(array_fruit.indexOf(currentfruit) == 2 ){
       trace("melon");
    } else {
       trace("no melon");
       appelsCollected++;
    }
}

indexOf takes two arguments. The first is the exact element you are searching for. The second argument is the index position to start the search from. The default is position 0.

See the API documentation here. (Always good to give these a quick read first).

edited Oct 30, 2016 at 16:33

answered Oct 30, 2016 at 16:16

Neal Davis

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3 Comments

tatactic Over a year ago

Sorry for my long answer @NealDavis I try my best to understand English :( I'm sure that null and You have a better answer. :(

tatactic Over a year ago

Do you're able to understand me when I write in English? Best regards! Nicolas.

Neal Davis Over a year ago

You do quite well with English! No need to apologize. We should keep these comments to the matter at hand, though, I think.

Vesper · Accepted Answer · 2016-10-31 01:11:03Z

0

You should use is operator here, for better coding. What if you'd change the positions of classes in your arrays?

if ((currentfruit is appel1_mc) || (currentfruit is appel2_mc)) {
    // apple
}

answered Oct 31, 2016 at 1:11

Vesper

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Comments

tatactic · Accepted Answer · 2016-10-31 16:55:13Z

0

Just in pseudo code to figure a possible way to deal with this issue. On the timeline :

import com.fruits.Fruit;
import com.fruits.Melon;
import com.fruits.Apple
var fruit_1:Melon = new Melon();
var fruit_2:Apple = new Apple();
if(fruit_1 is Melon){
    trace("anyway my SuperclassName is : " + fruit_1.getType());
    trace (fruit_1.getMyType());
    trace("");
}
if(fruit_2 is Apple){
    trace("anyway my SuperclassName is : " + fruit_2.getType());
    trace (fruit_2.getMyType());
    trace("");
}

in com.Fruit.as :

package com.fruits {
    public class Fruit {
        import flash.utils.getDefinitionByName;
        import flash.utils.getQualifiedClassName;
        import flash.utils.getQualifiedSuperclassName;
        public function Fruit() {
            trace ("I'm a Fruit");
        }
        public function getType():String{
            var type:String = getQualifiedSuperclassName(this)
            var str:String = (type);
            return str;
        }
    }
}

In com.Melon :

package com.fruits {
    public class Melon extends Fruit {
        import flash.utils.getDefinitionByName;
        import flash.utils.getQualifiedClassName;
        import flash.utils.getQualifiedSuperclassName;
        public function Melon() {
            super();
            trace ("Melon says : ");
            trace (" because I'm Fruit and not happy to be a Melon");
            trace("");
        }
        public function getMyType():String{
            var type:String = getQualifiedClassName(this)
            var str:String = ("Im a " + type);
            trace("Class said :  I worth nothing because I'm an Fruit and not proud to be an Melon");
            str += "\n" + "but in fact I'm a " + getQualifiedSuperclassName(this)
            return str;
        }
    }
}

In com.Apple :

package com.fruits {
    public class Melon extends Fruit {
        import flash.utils.getDefinitionByName;
        import flash.utils.getQualifiedClassName;
        import flash.utils.getQualifiedSuperclassName;
        public function Melon() {
            super();
            trace ("Melon says : ");
            trace (" because I'm Fruit and not happy to be a Melon");
            trace("");
        }
        public function getMyType():String{
            var type:String = getQualifiedClassName(this)
            var str:String = ("Im a " + type);
            trace("Class said :  I worth nothing because I'm an Fruit and not proud to be an Melon");
            str += "\n" + "but in fact I'm a " + getQualifiedSuperclassName(this)
            return str;
        }
    }
}

This is just an idea, tell me more about your target and if this may help You... Best regards Nicolas.

PS : I'm sorry but my English is really bad. so I tried to figure me the issue...

You may perhaps forget about indexOf and use addChild anytime You want to set an object/instance over another one.... So You don't have to check about the indexes. addChild(some old Child) will make the "old Child" be on the the last index (over the other instances). Sorry I didn't wrote your code but the title said that you want to check if the fruit is a Melon or an Apple... Sorry if I misunderstood. :(

edited Oct 31, 2016 at 16:55

answered Oct 31, 2016 at 16:42

tatactic

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4 Comments

tatactic Over a year ago

I'm sure that @null have understand your question, so read him first! I just do my best This is a good exercise for me

Neal Davis Over a year ago

indexOf has nothing to do with z-order (which is what you're referring to with your addChild comment). indexOf refers to the index position in an array. As in var arr:Array = [6,5,4,3,2,1]; trace(arr.indexOf(6)); returns 0 because 6 is in the 0th position of the array.

tatactic Over a year ago

Sorry @NealDavis, I try to to my best to understand and answer. Most of time, I don't really understand the question. I just do my best to learn English and don't forget AS3 because I had to stop my work due to health reasons. THX for your comments! I really appreciate them!

tatactic Over a year ago

Now, I finally understood your comment. My fault!

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