RE: [Newbie] Proper class releasing

FROM : Jon Keon
DATE : Fri Jun 06 19:59:25 2008

Hi Vijay,



Thanks for the response.



The line [newBaddie attachManagerRef:self]; is passing itself (the
baddie manager) to the Baddie instance so that when the Baddie has
expired it can call [managerRef removeMe:self] which tells the manager
to remove the Baddie from its array.



I'm gathering this is the wrong way to do things.



Am I correct is saying that because I passed the manager to the Baddie,
the Baddie now has a pointer to the manager. So when the Baddie
deallocs, it tries to release the manager as well?





Thanks,

Jon



From: Vijay Malhan [mailto:vijay.<email_removed>]
Sent: Friday, June 06, 2008 1:48 PM
To: Jon Keon
Cc: Cocoa Developer List
Subject: Re: [Newbie] Proper class releasing





On Fri, Jun 6, 2008 at 9:41 PM, Jon Keon <<email_removed>>
wrote:


Hi All,

I'm having a problem with creating new instances of classes after other
instances of them have been released.

I have a class called BaddieManager.

In this class I have a NSMutableArray that holds instances of Baddies.

So I create a new instance, place it my array and when the Baddies life
expires, I remove it from the array. This then causes the instance to
dealloc but then the next time I call my populateBaddies function the
whole program crashes with no error message. Any help would be greatly
appreciated.

Thanks,
Jon

//populate the array with baddies
-(void) populateBaddies {

      while (baddieCount < baddieLimit) {


              //Create a new instance of my baddie
              PBaddie *newBaddie = [[PBaddie alloc] init];
              //add him to the view
              [gameView addSubview:newBaddie];
              //give him a reference of the manager
              [newBaddie attachManagerRef:self];



What is the above method doing? I hope it is not retaining or releasing
the reference it is keeping in it's dealloc method. That will cause a
crash when next time this obj is accessed after releasing your *baddie
object*. Normally to maintain a weak reference delegate pattern is used,
where delegate is never retained or released.



If you are doing that right, see if you get a crash log/stack trace or
any logs in sys-console.



- Vijay



   
                 //animate him
                 [newBaddie animateBaddie:NULL finished:0];
                 //add him to the array
                 [pBaddieArray addObject:newBaddie];
                 //release the temp variable
                 [newBaddie release];
                 //increment the count
                 baddieCount = [pBaddieArray count];
   
         }
   
   }
   
   //Removes the Baddie from the array and destructs him
   -(void) removeMe:(PBaddie *) pBad {
   
         //remove from the game view - we don't want to see it
anymore
         [pBad removeFromSuperview];
   
         //remove the baddie from the array (Causes the Baddies
dealloc
   method to fire)
         [pBaddieArray removeObject:pBad];
         //update the count
         baddieCount = [pBaddieArray count];
   
   }
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