> I don't really know if I am right, because of lack of experience. Please,
> correct me if I'm wrong, but... Why would anyone write code like that?
>
> I mean, if one subclasses NSObject and doesn't override +init, it will return
> self -- or, maybe, nil -- anyways.
>
> So, I would assume that [super init] would only be called inside an +init or
> +initWithWhatever: method, right? Like this:
>
> + (id*)init
> {
> [super init];
> // initialize some other instance vars, etc. ...
> [return self];
> }
>
> So, in case a class' +init method can return nil and you want to subclass it,
> the code should be more like:
>
> + (id*)init
> {
> if ([super init] != nil)
> {
> ...
> [return self];
> }
> else
> {
> return nil; // or return something else, throw an exception,
> whatever...
> }
> }
>
> I am just curious, because I think it's strange to write "self = [super
> init]" anywhere other than in an overriden +init. Am I right?
If you declare +init, you are writing a static method, not an instance method.
The static initialiser is +initialize and you would not call [super
initialize], as the superclass's initialiser is called before your class's.
-init is an instance method and it is that method that you should be
overriding. Either that, or calling [super init] from your own instance
initialiser.
Your first example calls [super init] but doesn't assign it to self. Which is a
good thing because self, in the case of a static initialiser, returns the
Class, not the instance.
BTW, you should not declare id* as the return type, it should be simply id.
- (id) init
{
if (self = [super init])
{
// rest of initialisation
}
return self;
}
Joanna
--
Joanna Carter
Carter Consulting
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