ack? Why does this code make my game freeze

[Soljaragz]

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

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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]

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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]

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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]

wow, as Linus Torvalds said

"If you need more than 3 levels of indentation, you're screwed anyway, and should fix your program."

Games published by our own members! Check 'em out!

[Riven]

Indeed, this looks so much better

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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]

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

 thanks guys let me see what happens

[Soljaragz]

edit: [nvm]

[Soljaragz]

um lol it still freezes...hmm

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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]

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

Use an iterator and use iterator().remove

[Soljaragz]

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]

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

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

Games published by our own members! Check 'em out!

[Soljaragz]

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

[Riven]

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]

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]

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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:

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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]

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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]

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]

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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]

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

[Riven]

So you didn't see either "before" or "after" printed? Right... as still you're telling me the call to remove() is freezing...

[Soljaragz]

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

[Soljaragz]

Also, inside the file I uploaded i made a typo that doesnt really effect freezing, but it still is wrong

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if(elementsArray[i][k]!=null) {    if(elementsArray[i][k].getElement().equals("ground"))       groundList[elementsArray[i][k].getCol()] = elementsArray[i][k];    else if(elementsArray[i][k].isEnemy())       enemyList[i*levelArray[0].length()+k].add(elementsArray[i][k]);    else       enemyList[i*levelArray[0].length()+k].add(elementsArray[i][k]);                       }

   
should be replaced with

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if(elementsArray[i][k]!=null) {    if(elementsArray[i][k].getElement().equals("ground"))       groundList[elementsArray[i][k].getCol()] = elementsArray[i][k];    else if(elementsArray[i][k].isEnemy())       enemyList[i*levelArray[0].length()+k].add(elementsArray[i][k]);    else       itemList[i*levelArray[0].length()+k]=elementsArray[i][k]; }

[Jeff]

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

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

when you modify a lsit in the middle of a loop over ist indexes you have no gaurantees of what it does to the indexes.  Its totally implemntation dependant.

if its working for you, your just gettign lucky.

Use Iterators, thats what they a re for.

[Soljaragz]

http://s53.yousendit.com/d.aspx?id=2NPP2M8HHFAQ03H9KXGMQL3GSJ
^^^ updated file,
[edit[ alrite ill try iterator

[oNyx]

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

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

when you modify a lsit in the middle of a loop over ist indexes you have no gaurantees of what it does to the indexes.  Its totally implemntation dependant.

if its working for you, your just gettign lucky.

Use Iterators, thats what they a re for.

http://java.sun.com/j2se/1.5.0/docs/api/java/util/AbstractList.html#remove(int)

"Removes the element at the specified position in this list. Shifts any subsequent elements to the left (subtracts one from their indices)."

So, I'm not lucky. Its the way its (AbstractList ) supposed to work. And yea the indices change, but only of those I already checked.

---

edit: Duh... Applets... you know that there is lots of caching going on and that you dont necessarly see the changes in effect (if you're using a browser), right?

Short answer: Use the appletviewer for testing.

[Soljaragz]

i dont understand how to use appletviewer so screw that, but

riven, instead of using s.o.p. i use setBackground(Color.red) to test if a certain place was accessed. and if i have the setBackground(Color.red) in my catch block, then it does change the color.

[Soljaragz]

ok i dont know how to convert everything from a for loop to a iterator

so far

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eIterator = eList[enemyIndex].iterator(); while(eIterator.hasNext()) {                                if( !quix.getAttackRect().intersects( ( (Enemy) eIterator.next() ).getBounds() ) )    {       continue;    }                                if(level.attackElement( enemyIndex,i,50 ))    {       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");           } }

how do i convert this part because i need a particular index;

1	if(level.attackElement( enemyIndex,i,50 ))

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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;    }

[Soljaragz]

ok i tried the iterator but it still freezes

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(index count already declared to 0 earlier) eIterator = eList[enemyIndex].iterator(); while(eIterator.hasNext()) {        if( !quix.getAttackRect().intersects( ( (Enemy) eIterator.next() ).getBounds() ) )    {       continue;    }        if(level.attackElement( enemyIndex,currentIndex,50 ))    {          System.out.println("before");          try{          currentIndex--;          eIterator.remove();          }          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");    }    currentIndex++; } currentIndex=0;

[Soljaragz]

blah i think i fixed it...............thanks guys




btw someone tell me how open the applet with an appeltviewer, i cant get it to work

[Riven]

1. www.google.com
2. See 3rd result.

[swpalmer]

i dont understand how to use appletviewer so screw that, ...

You expect help from people when you have that attitude?

Did you read the docs?
What about them didn't you understand?
Ask some reasonable questions and you will get better help. 
(Or you can respond with "screw that" and see how long it is tolerated.)