Re: [Newbie] Proper class releasing
Re: [Newbie] Proper class releasing
- Subject: Re: [Newbie] Proper class releasing
- From: "Vijay Malhan" <email@hidden>
- Date: Fri, 6 Jun 2008 23:43:32 +0530
On Fri, Jun 6, 2008 at 11:29 PM, Jon Keon <email@hidden> wrote:
> 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?
>
Yes, if you are releasing that pointer in the dealloc. Also if you have
retained the reference of your manager in baddie class, you'll get yourself
in a retain cycle. So, I'll suggest you to review your design as suggested
by Kyle. You can see Cocoa MVC documentation for more details. Thanks.
Link:
http://developer.apple.com/documentation/Cocoa/Conceptual/CocoaFundamentals/CocoaDesignPatterns/chapter_5_section_4.html
- Vijay
>
>
>
>
> Thanks,
>
> Jon
>
>
>
> *From:* Vijay Malhan [mailto:email@hidden]
> *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@hidden> 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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