Re: messaging the object that allocated an object
Re: messaging the object that allocated an object
- Subject: Re: messaging the object that allocated an object
- From: Ken Thomases <email@hidden>
- Date: Wed, 14 May 2008 14:40:07 -0500
On May 14, 2008, at 12:43 PM, James Churchman wrote:
WebViewController *webViewController = [[WebViewController alloc]
init];
So now i have all my code running in my "webViewController" controller
object, but i really need to call a method that is in the "
MainViewController", which is in the the class "above",
that actually initialized the "webViewController".
(in fact i really want to message something in AppDelegate but
allowing me
to message the class "above" should allow me
to extend this principle up future)
How is this posible, can i pass an id of the "parent"
(MainViewController) object
to the webViewController that will allow it to pass messages back
to it?
There's no "automatic" way for an object to receive a pointer to the
object which allocated it. You can pass it in explicitly. To
accomplish that, you would implement an alternative initializer
method which takes the pointer as a parameter. Something like:
- (id) initWithRelatedObject:(MyClass*)relatedObject
{
// ...
}
The internals of that initializer method would look mostly the same
as a typical initializer but would probably make use of relatedObject
somehow. You should read up on the whole topic of designated
initializers, though, to make sure you cover your bases properly.
You want to take care of the possibility that a client of your
WebViewController will try to use one of the initializers of the
superclass, and you want your new initializer to invoke the proper
initializer of the superclass.
That said, if you want to access the delegate of the main application
object, you can just use [NSApp delegate] to obtain it. That may be
a more appropriate design, depending on what you're actually trying
to achieve.
Cheers,
Ken
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