ack? Why does this code make my game freeze

Soljaragz · February 5, 2006, 7:12am

my game freeze whenever an enemy dies…can someone tell me why?

enemyIndex = row*level.getLevelWidth()+quix.getCol();
			
			
if(!quix.facingLeft())
{
	for(int i=0;i<eList[ enemyIndex ].size();i++)
	{
		if(eList[ enemyIndex ].get(i) != null)
		{
			if( quix.getAttackRect().intersects( ( (Enemy) eList[ enemyIndex ].get(i) ).getBounds() ) )
			{
				if(level.attackElement( enemyIndex,i,50 ))
				{	
					eList[ enemyIndex ].remove(i); //THIS SPECIFICALLY FREEZES THE GAME
					i--;
					setBackground(Color.green);
							
			       }	
							

		      }
	     }
						
					
      }
					
}
/code]

public boolean attackElement(int arrayIndex, int listIndex, int damage)
	{
		
		((Enemy)enemyList[ arrayIndex ].get(listIndex) ).attack(damage);
		if( ( (Enemy)enemyList[ arrayIndex].get(listIndex) ).getHp()<=0)
		{
			elementsArray[arrayIndex/getLevelWidth()][arrayIndex%getLevelWidth()] = null;
			enemyList[arrayIndex].remove(listIndex);
			return true;
		}
		else
			return false;
	}

oNyx · February 5, 2006, 8:13am

for(int i=al.size()-1;i>=0;--i) {
	Thingy t=(Thingy)al.get(i);
	if(t.isDead())
		al.remove(i);
}

Walk backwards through it like that. Like if you remove element 2, the elements 1 and 0 will stay at their place.

f.l.x · February 5, 2006, 11:46am

wow, as Linus Torvalds said

[quote]“If you need more than 3 levels of indentation, you’re screwed anyway, and should fix your program.”
[/quote]

Riven · February 5, 2006, 12:56pm

Indeed, this looks so much better

if(quix.facingLeft())
return;

for(int i=eList[ enemyIndex ].size()-1;i>=0;i--)
{
	if(eList[ enemyIndex ].get(i) == null) // do you really have null values here?
	   continue;

	if(! quix.getAttackRect().intersects( ( (Enemy) eList[ enemyIndex ].get(i) ).getBounds() ) )
            continue;

	if(level.attackElement( enemyIndex,i,50 ))
	{	
	   eList[ enemyIndex ].remove(i); //THIS SPECIFICALLY FREEZES THE GAME
	   i--;
	   setBackground(Color.green);			
       }		
}

Soljaragz · February 5, 2006, 6:11pm

lol ok i guess i don’t really have null values
and i forgot there was a continuecommand lol

thanks guys let me see what happens

Soljaragz · February 5, 2006, 6:20pm

edit: [nvm]

Soljaragz · February 5, 2006, 6:31pm

um lol it still freezes…hmm

	for(int row=0;row<4;row++)
	   {
		enemyIndex = row*level.getLevelWidth()+quix.getCol();
							
		if(!quix.facingLeft())
		{
			for(int i=eList[ enemyIndex ].size()-1;i>=0;i--)
			{
									
				if( !quix.getAttackRect().intersects( ( (Enemy) eList[ enemyIndex ].get(i) ).getBounds() ) )
				{
					continue;
				}
									
				if(level.attackElement( enemyIndex,i,50 ))
				{
  					eList[ enemyIndex ].remove(i); //THIS SPECIFICALLY FREEZES THE GAME
   										
   					setBackground(Color.green);
       				} 
			}
                 }
									
           }

Jeff · February 5, 2006, 8:02pm

Yo ucannot act on the lsit directly from within a loo pthat iterates over it.

Use an iterator and use iterator().remove

Soljaragz · February 5, 2006, 8:06pm

why can’t I???

it removes it from the list, that would make sense so why wouldnt that work?

and if i use iterator I would i have to use listiterator? cause I have to go backwards right???

oNyx · February 5, 2006, 8:32pm

You can do that just fine. I’m using that kind of construct (see my previous post) in a couple of places.

Soljaragz · February 5, 2006, 8:34pm

onYx , it still freezes though even when i go backward, check my code

Riven · February 5, 2006, 8:55pm

remove(int) just can’t freeze

There just is nothing as a freeze in Java for this situation.
You might have an uncaught Exception that’s going up the stack and there the handlings makes it block, or it’s not caught anywhere at all, the current thread will just die.

Try this;
System.out.println(“before”);
try{
remove(i);
}
catch(Exception exc)
{
exc.printStackTrace(System.out);
System.exit(0); // makes sure this is the last data that turns up in the output
}
System.out.println(“after”);

Soljaragz · February 5, 2006, 9:29pm

yeh i tried that already, and it didn’t freeze but then

WOULDNT IT MEAN THAT THE LINE
“remove(i)” DIDNT WORK?

why would i have to try and catch it? it should just work without it

oNyx · February 5, 2006, 9:34pm

import java.util.*;

public class Remove{
	public static void main(String[]args){
		ArrayList al=new ArrayList();
		System.out.println("filling with 0-9");

		for(int i=0;i<10;i++)
			al.add(new Integer(i));

		System.out.println("removing all even numbers");
		for(int i=al.size()-1;i>=0;--i)
			if(((Integer)al.get(i)).intValue()%2==0)
				al.remove(i);

		System.out.println("looks like this now:");
		for(int i=0;i<al.size();i++)
			System.out.println((Integer)al.get(i));

		al.clear();

		System.out.println("filling with 0-9");
		for(int i=0;i<10;i++)
			al.add(new Integer(i));

		System.out.println("removing all numbers which are bigger than 5");
		for(int i=al.size()-1;i>=0;--i)
			if(((Integer)al.get(i)).intValue()>5)
				al.remove(i);

		System.out.println("looks like this now:");
		for(int i=0;i<al.size();i++)
			System.out.println((Integer)al.get(i));

		al.clear();

		System.out.println("filling with 0-9");
		for(int i=0;i<10;i++)
			al.add(new Integer(i));

		System.out.println("removing all numbers which are smaller than 5");
		for(int i=al.size()-1;i>=0;--i)
			if(((Integer)al.get(i)).intValue()<5)
				al.remove(i);

		System.out.println("looks like this now:");
		for(int i=0;i<al.size();i++)
			System.out.println((Integer)al.get(i));

	}
}

output:

filling with 0-9
removing all even numbers
looks like this now:
1
3
5
7
9
filling with 0-9
removing all numbers which are bigger than 5
looks like this now:
0
1
2
3
4
5
filling with 0-9
removing all numbers which are smaller than 5
looks like this now:
5
6
7
8
9

See? Works as advertised.

Must be something else.

Soljaragz · February 5, 2006, 9:37pm

System.out.println("before");
											try{
											eList[ enemyIndex ].remove(i);
											}
											catch(Exception exc)
											{
											setBackground(Color.red);
											exc.printStackTrace(System.out);
											System.exit(0); // makes sure this is the last data that turns up in the output
											}
											System.out.println("after");

didn’t work right.

but onxy, when i take out "eList[ enemyIndex ].remove(i); " it doesnt freeze, and every other part of prog dealing with it makes sense imo…

would somebody want to read my entire prog??? cause apparently nothings working

Soljaragz · February 5, 2006, 11:02pm

THis is my entire game folder, can someone plz take a look at it because Im desperate =( and it freezes when i kill something no matter what i try
http://s65.yousendit.com/d.aspx?id=3J0ZCLDG92C0W0FVSXN5274MGU

Riven · February 5, 2006, 11:05pm

Soljaragz:

System.out.println("before");
											try{
											eList[ enemyIndex ].remove(i);
											}
											catch(Exception exc)
											{
											setBackground(Color.red);
											exc.printStackTrace(System.out);
											System.exit(0); // makes sure this is the last data that turns up in the output
											}
											System.out.println("after");

didn’t work right.

What kind of useless response is that. At least tell what happened.

Soljaragz · February 5, 2006, 11:24pm

sry…
lol the thing is NOTHING HAPPENED LOL, it just froze and thats it

Riven · February 5, 2006, 11:40pm

So you didn’t see either “before” or “after” printed? Right… as still you’re telling me the call to remove() is freezing…

Soljaragz · February 5, 2006, 11:47pm

no i didnt see either, system.out.println works for applets too?