CODEWITHSUNDEEP
javaarrayslibgdx
Tautvydas Jalinskas
Tautvydas Jalinskas

Reputation: 129

Removing something from array but game crashes

I have and array where I create few swords on the tiled map and when i step on them they need to be deleted but when I step on them game chrashes.

at java.util.ArrayList$Itr.checkForComodification(Unknown Source) at java.util.ArrayList$Itr.next(Unknown Source)

MY CODE:

I guess the loop is looking for the object even if its deleted?

private List<Sword> swords = new ArrayList<Sword>();

I create them one time:

public GameRender(GameWorld world, int gameHeight) {
    for (int i = 0; i<100 ; i++ ) {
        swords.add(new Sword());
        }

When i step on it:

for (Sword sword : swords) { 
        if(playery+7>=sword.position.y && playery+7<=sword.position.y+tilesize
        && playerx+7>=sword.position.x &&playerx+7<=sword.position.x+tilesize) {
                sword.pickMe();   
                swords.remove(sword);
        }
    }

There is other loop in render():

for (Sword sword : swords) {
        sword.createMe();
    }

I dont think you need to see the Sword class. If you do i'll put it in here. How do i fix it so I dont get the error?

Upvotes: 0

Views: 103

Answers (1)

EpicPandaForce
EpicPandaForce

Reputation: 81588

for (Sword sword : swords) { 
        if(playery+7>=sword.position.y && playery+7<=sword.position.y+tilesize
        && playerx+7>=sword.position.x &&playerx+7<=sword.position.x+tilesize) {
                sword.pickMe();   
                swords.remove(sword); //this line throws ConcurrentModificationException
        }
}

Due to how the enhanced for loop works, you either need to use an Iterator<Sword> to remove it:

Iterator<Sword> iterator = swords.iterator();
while(iterator.hasNext())
{
    Sword sword = iterator.next();
        if(playery+7>=sword.position.y && playery+7<=sword.position.y+tilesize
        && playerx+7>=sword.position.x &&playerx+7<=sword.position.x+tilesize) {
                sword.pickMe();   
                iterator.remove();
        }
}

Or the following:

  for (int i = 0; i < swords.size(); i++) { 
        Sword sword = swords.get(i);
        if(playery+7>=sword.position.y && playery+7<=sword.position.y+tilesize
        && playerx+7>=sword.position.x &&playerx+7<=sword.position.x+tilesize) {
                sword.pickMe();   
                swords.remove(i--);
        }
  }

Upvotes: 3

Related Questions