Help me understand -(void)dealloc

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Help me understand -(void)dealloc

(9 posts) (6 voices)

Started 2 years ago by SonnyBurnette
Latest reply from malphigian

Tags:

SonnyBurnette
Member

I am a little confused on what I am supposed to and not supposed to release. From what I keep reading Cocos2d handles releasing itself. Is that true? Does that mean that if I alloc anything that is a cocos2d node (Sprite, AtlasSprite, AtlasSpriteManager, MenuItem, etc.) I don't have to list it as [myNode release] in the dealloc? I still have to release properties in my classes though correct?

Example:
@property (readwrite,copy) NSString *name;

Sorry but I am really confused with this and while my game isn't big, I do want to follow the rules and keep it clean.

Posted 2 years ago #
Clain
Member
cocos or not, it's always the same rule : you need to release the stuff you alloc'd init'd and the stuff you got from calling a method starting with copy. Example with Sprite in your init method (or anywhere else in your cocos node) :

if you do
```
mySprite = [Sprite spriteWithFile:@"someSprite.png"];
[self addChild:mySprite];
```
then there's no need to release mySprite in the dealloc method

but if you do
```
mySprite = [[Sprite alloc] initWithFile:@"someSprite.png"];
[self addChild:mySprite];
```
then you'll have to release mySprite in the dealloc method
Posted 2 years ago #
SonnyBurnette
Member

EXACTLY the answer I was looking for.

Thanks!

Posted 2 years ago #
SonnyBurnette
Member
Ok I spoke too soon.

What about things like this:
```
@property (readwrite,copy) NSString *name;
@property (readwrite,copy) NSString *status;
```
Do I need to set them to nil?
Posted 2 years ago #
Codemattic
Moderator
All of your object's properties should be set to nil in -dealloc.
```
-(void) dealloc
{
 self.myProperty=nil;
 self.myProperty2=nil;
 // etc...
 [super dealloc];
}
```
Posted 2 years ago #

Codemattic
Moderator

In Clain's example, its unclear if mySprite is a temporary variable or a property. So just for completeness sake:

If its a property then:

self.mySprite = [Sprite spriteWithFile:@"someSprite.png"];
[self addChild:mySprite];

self.mySprite = [[[Sprite alloc] initWithFile:@"someSprite.png"] autorelease];
[self addChild:mySprite];

or if you are sure this is the first time you are setting/initializing mySprite

mySprite = [[Sprite alloc] initWithFile:@"someSprite.png"];
[self addChild:mySprite];

and then in dealloc:

self.mySprite = nil;

if mySprite is a temporary variable:

Sprite *mySprite = [Sprite spriteWithFile:@"someSprite.png"];
[self addChild:mySprite];
//nothing else needed

Sprite *mySprite = [[Sprite alloc] initWithFile:@"someSprite.png"];
[self addChild:mySprite];
[mySprite release];

whew! Cant wait for automatic garbage collection to make it to the iPhone OS!

Posted 2 years ago #

rolando
Moderator

Not sure if you really need to set to nil the property in the dealloc method. You should call [mySprite release], but I guess that calling self.mySprite = nil in the default setter, also releases the property... so it might have the same effect.

To make things clearer: you *have* to release every object *you* init. The release can be explicit (calling [someInstance release], or by calling the default setter with nil: self.someProperty = nil).

Codemattic: That's one of the main reasons why I started creating ShinyCocos: ruby takes care of all the GC :-)... Our first game (test game) using ShinyCocos was submitted to apple about one week ago, so we're still in expectation about what apple has to say about it. We're pretty confident, though.

Posted 2 years ago #
jacobodonnell
Member

so if i do NOT allocate the sprite myself then when will it get released? sometime close to when i remove the sprite from its parent node?

Posted 2 years ago #
malphigian
Member

When you add a sprite to a parent, the parent increases the sprite's retain count by 1, when you remove the child, it reduces the retain count by 1. When the retain count hits 0, the object will be gone not long after.

For me what got everything to count was making liberal use of this:
NSLog([NSString stringWithFormat:@"My Object Retain Count: %d", [YourObject retainCount]]);

Pretty obvious, but it helped me really understand when objects were getting retained and released.

Posted 2 years ago #

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