CODEWITHSUNDEEP
kotlinlibgdxbox2dkotlin-coroutineskotlin-android-extensions
keepupwiththetimes
keepupwiththetimes

Reputation: 57

For loop while removing items from ArrayList

I am making a game in Kotlin.Using Libgdx and Box2d

1.function creates bodies via Box2d and adds these bodies in bodyArrayList:ArrayList

2.function creates textures and adds these textures in textureArrayList

3.function is matching items of bodyArrayList with items of textureArrayList. The function has for loop.

4.function is removing bodies when crash a wall.

5.function is removing textures when crash a wall.

All functions are working in update() method. All these are working perfectly. However because I cannot remove items of te ArrayLists while for loop works on these ArrayLists, items of ArrayList is increasing and the game is starting slowing downn 1 hour later. The ArrayLists' size is going up as you guess. If I try to remove items of ArrayLists I am taking exceptions in matching() function as you guess.

My question is how can I remove these items from ArrayLists while "for loop" is working in a safe manner.

1.function creates bodies

var body = makeBody()
 bodyArray.add(body)

2.function creates textures

var texture=makeTexture()
 textureArray.add(texture)

3.function is matching items of bodyArrayList with items of textureArrayList

for (i in 0..bodyArray.size-1) {

 textureArray[i].setPosition(bodyArray[i].position.x, bodyArray[i].position.y)
}

4.funtion is removing bodies when crash a wall.

override fun beginContact(contact: Contact?) {
        val userDataA = contact!!.fixtureA.userData.toString()
        val userDataB = contact.fixtureB.userData.toString()

            if ((userDataA == "ball" && userDataB == "wall")){
            val bodyA=contact.fixtureA.body
           Gdx.app.postRunnable(Runnable(){
                run(){
                    world.destroyBody(bodyA) } })
 }

5.function is removing textures when crash a wall.

for (texture: MyTextures in MyTextures.getList(Ball::class.java.canonicalName)) {
            if (ball.overlaps(wall)) {
                ball.remove() }
        }

Upvotes: 2

Views: 1677

Answers (2)

HamidSayyah
HamidSayyah

Reputation: 423

if you are using badLogic Array class you can give your texture class to it and dispose every item of it in dispose method

private val texture = Texture("badlogic.jpg")
private val myArray = Array<Texture>()

    fun dispose(){
       myArray[i].dispose()
    }

this is the link for more info on textures...

also you can dispose Screen Class

Upvotes: 0

Rajan Kali
Rajan Kali

Reputation: 12953

You can use Iterator to remove items from Collections while iterating

val list = arrayListOf<Int>()
val listIterator = list.iterator()
while(listIterator.hasNext()){
    //get item
    val item = listIterator.next() 
    //items can be removed safely using
    listIterator.remove()
}

Upvotes: 1

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