Inside an initialization method, I have the following code
- (id)init {
self = [super init];
if (self) {
UIButton *tempButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
tempButton.frame = CGRectMake(0,0,300,44);
// some custom code...
self.myButton = tempButton;
}
return self;
}
Where myButton is a retained property.
I know that, for what concerns memory management rules, this method equals this other:
- (id)init {
self = [super init];
if (self) {
UIButton *tempButton = [[UIButton alloc] initWithFrame:CGRectMake(0,0,300,44)];
// some custom code...
self.myButton = tempButton;
[tempButton release];
}
return self;
}
But in this case I need to use the first "version" because the buttonType property is readonly and I cannot change it after having the button initalized.
Since I find myself using the "non init-release" version in multiple methods all over my application, and for several object (most of them are NSString), my question is: not counting in this case the assignment to the property which retains the object, when the tempButton object will be released? Maybe at the end of the method/if statement? Or will the first "version" lead to an increased memory usage, since the object is not being released right away but after a certain amount of time?
I think you're a bit confused here: in both of your snippets, you create a tempButton object, but then you're assigning it to self.myButton. At that point, both tempButton and self.myButton are pointers to the same object. Now, presumably the myButton @property you're using is a strong property, so by assigning tempButton to it, you increase its retain count, and therefore in either version of the code it would have a retain count of +1 at the end, and would not be dealloc'ed.
If, hypothetically, myButton wasn't a strong property, then there would be an error in your code, and in both cases tempButton would be prematurely released and dealloc'ed. Here's what would happen in the two cases:
In your first version, since you're getting tempButton comes from something other than an init or copy method, it gets a retain count of +1, but is autoreleased. At the end of the current iteration of the run loop, the autorelease would kick in, bringing its retain count to 0 and causing it to be dealloc'ed.
In the second version, you first get a tempButton with a retain count of 1 because it's coming from an init method. But later on you explicitly release it, bringing its retain count to 0, at which point it is immediately dealloc'ed.