So, I have a problem. I need to loop through an arraylist of Zombies. The method that does this is inside of a Zombie object. I need to loop through all zombies except itself. So I tried this:
if(zombie != this)
Do crap
But that did not work. So what do I do? Googling has brought me nowhere.
This should work:
if(!(zombie instanceof this)){
}
I don’t see how that would work. But, I’ve never tried/seen it to know. (In reference to Phased’s solution)
You could just give each zombie an id and check that.
It does work, I checked it with my screen manager class.
for example
if(monster instanceof skeleton)
would return true if monster is a skeleton, and continue the if statement.
if you used
if(!(monster instanceof skeleton))
the if statement would only continue if the statement returned false, as the ! wants a non true value from
(monster instanceof skeleton)
I fixed it up just before you replied, it was fine until i refreshed it, guess the save didn’t actually save.
[s]monsters and skeletons was just a easier example to explain the code.
Well, what is “this”, you gave us a snippet of your code.
if(!(zombie instanceof this)){
}
[/s]
After re reading it a few times, I think i miss understood what you wanted, troncoso is right, you would need to have a unique ID for every single entity and compare the entitys ID with each other.
What are you trying to do that will compare a zombie with its self?
First of all, why does the Zombie class have access to an ArrayList of Zombies? Secondly, if(zombie != this) should work as that checks for instance equality, which is exactly what you want.
“instanceof” is not the answer here, and was actually used incorrectly everywhere in this thread. You can only check “instanceof” with a class type, not an object. “instanceof this” or “instanceof anotherObject” will throw an error.
If giving the entities IDs is used only for this operation, then this is a pointless misuse of memory.
I have to agree. There’s no reason for your Zombie class to have an ArrayList of Zombies. Then how does your horde work? Every Zombie instance has its own ArrayList of Zombies? That’s startlingly inefficient.
Cycling through the same list/array in every single zombie instance is still a really bad idea, not to mention it doesn’t make any sense (OOP wise). If you’re going to do something to the zombies of the World do it either in the World class or make a separate class.
Look at this:
(This does not go inside the zombie class ofcourse)
for(int zom = 0; zom < getWorld().getZombies().size(); zom++) {
for(int zom2 = zom+1; zom2 < getWorld().getZombies().size(); zom2++) {
Zombie zombie1 = getWorld().getZombies().get(zom);
Zombie zombie2 = getWorld().getZombies().get(zom2);
//Colission stuff
}
}
The name does not not bother me, but instanceof does 
No probelm anyways.
If you’re on OOP: world -> horde -> zombie where horde is holding zombie arraylist. There can be more than one horde in a world and more than one zombie in a horde.
If you’re on the ES like Artemis, well, it’s obvious that the corresponding system will fetch entire entities with zombie component and presents it as list. You just need to design that only ONE system that will need to fetch/process that list, ONCE in a loop if you can.
Either way, his point still holds…
…Managed
My point is that it’s too mess to have a world which only single (you only have one right?) to handle all entities. Some entities share similarity that can make them to be grouped.
Thats a pun refering to the Marauder’s Map in Harry Potter which had to be wiped clean with the spell “Mischief Managed”
No one said that because there’s no reason you would ever need to do that…
Yes, but if I ask “How do I make a game without a game loop?”, are you going to tell me how to do that, or are you going to tell me that I shouldn’t be doing it that way?
(Assuming you’re referring to your collision code:)
You’re checking every possible collision twice!
(If you’re referring to your solution:)
“!=” works fine, as long as it’s the same object. If it’s not the same object… you have a problem.
!.equals() is a method which usually involves a few if() statements, and so will take more proccessing power then !=, which is only checking if both pointers are the same. However, the difference is tiny, and is not going to be something you need to change.
But either way, the collision detection should be done outside of the zombie class, which is what most people were telling you.