On Jul 5, 2009, at 6:10 AM, mmalc Crawford wrote:
On Jul 4, 2009, at 8:11 PM, WT wrote:
The following is ok, though, assuming that you have appropriately
declared myObject in your class (for example, as an instance
variable):
- (void)viewDidLoad
{
myObject = [[NSObject alloc] init];
}
In general, this is not recommended.
If you manipulate an instance variable anywhere other than in an
initialiser or a dealloc method, you should use a suitable accessor
method.
- (void)viewDidLoad
{
id anObject = [[NSObject alloc] init];
[self setMyObject:anObject];
[anObject release];
}
There is plenty of Apple sanctioned code that does not follow that
recommendation, both in sample code and in documentation.
Both are fine, but I would suggest something like the following,
just because it avoids code duplication:
- (void)viewDidUnload
{
[self dispose];
}
It is not clear here what is the benefit of "avoiding code
duplication" -- you're simply introducing another method that you
have to keep track of.
I think my explanation was clear enough. If you have lots of objects
to release in both viewDidUnload and dealloc, the chances of
forgetting to do so in both are non-negligible. Refactoring the common
release calls into a separate method puts them all in only one place.
- (void)dealloc
{
[self dispose];
// deallocation of stuff that was not unloaded
[otherStuff release];
}
This is missing:
[super dealloc];
as the final statement;
Indeed. That's the problem with copy/paste and doing things in Mail,
rather than from real code, ie, sometimes we all make silly mistakes.
Not an earth-shattering mistake to make in this list, though, since
you get a warning when trying to compile without the call to super.
- (void)dispose
{
[myObject release];
myObject = nil;
}
Again, you should use accessor methods rather than direct variable
manipulation.
Again, there is plenty of Apple sanctioned code that does not follow
that recommendation.
You can have -dispose be a private method of your class so it won't
be accessible outside of it. One big advantage of this separation
is that if/when you need to change your deallocations, you only
have to do it in one place.
Referring to this as "deallocations" is at best misleading. The
goal is to relinquish ownership of any objects you're holding on
to. This may or may not result in deallocation of those objects.
I think everyone understood what I meant. Sometimes I mess up because
of genuine confusion on my part and sometimes I mess up because of
multitasking. This time it was the latter.
Wagner
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