Re: Attributed Strings
Re: Attributed Strings
- Subject: Re: Attributed Strings
- From: Sherm Pendley <email@hidden>
- Date: Fri, 11 Mar 2005 17:24:22 -0500
On Mar 11, 2005, at 4:57 PM, Mike R. Manzano wrote:
Regarding NSAttributedStrings, the docs say for its init methods:
Returns an initialized object, which might be different than the
original receiver
Does this mean that I should autorelease my original object before
initing it? Like this?
NSAttributedString* aString = [ [ NSAttributedString alloc ]
autorelease ] ;
NSAttributedString* myActualString = [ [ aString initWithString:@"la
dee dah" ] retain ] ;
No, that's not what it means. It means you have to "chain" the +alloc
and -init together, like this:
NSAttributedString *aString = [[NSAttributedString alloc] init];
You can't do it in two separate calls, like this:
// ** incorrect code **
NSAttributedString *aString = [NSAttributedString alloc];
[aString init];
Because aString will no longer refer to the correct object; it will
refer to the original object returned by +alloc, not the one returned
by -init.
No special care needs to be taken with regards to memory management. If
-init needs to return a different object, it will automatically release
the original and retain the new one. So the normal rules - i.e. you've
created an object with +alloc, so you're responsible for releasing it
later - still apply as always.
The same thing is generally true of any +alloc/-init pair,
incidentally. It's *always* possible, and quite common for classes that
are members of a class cluster, for -init to return a different object
than the one it was called on. Why the document writers thought that
was worth special mention in NSAttributedString in particular, I don't
know - it's certainly not unique in that respect.
sherm--
Cocoa programming in Perl: http://camelbones.sourceforge.net
Hire me! My resume: http://www.dot-app.org
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