On 30 Jul 2013, at 15:44, Maxthon Chan <xcvi...@me.com> wrote:
> My common way of handling this would be NSNotificationCenter. It is a
> singleton so I am always sure that it is there, and I can wrap all parameters
> into the userInfo dictionary.
NSNotificationCenter is not a singleton:
> $ cat test.m
> #import <Foundation/Foundation.h>
>
> int main (int argc, char **argv)
> {
> @autoreleasepool
> {
> NSNotificationCenter *a = [[[NSNotificationCenter alloc] init]
> autorelease];
> NSNotificationCenter *b = [[[NSNotificationCenter alloc] init]
> autorelease];
> NSLog(@"%p, %p", a, b);
> }
> $ clang -framework Foundation test.m
> $ ./a.out
> 2013-08-07 09:13:25.508 a.out[6155:507] 0x7fcb1040a090, 0x7fcb1040a190
It just happens to have one instance (defaultNotificationCenter) which is
common to want to use in lots of locations in your program.
You can not “be sure that [a singleton] is there” any more or less than any
other class in your program.
For reference though, both designs for effectively making all objects in your
program global objects are pretty horrible for exactly that reason – making
everything effectively a global is just terrible design.
Tom Davie
_______________________________________________
Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com
This email sent to arch...@mail-archive.com
