Hi Quincey, Your suggested fix works fine, except I used -arrayForKey rather than -arrayValueForKey (which I couldn't find). Thanks for the explanation!
Cheers,
Martin
On Aug 10, 2012, at 07:15 AM, Quincey Morris
<quinceymor...@rivergatesoftware.com> wrote:
> On Aug 9, 2012, at 22:49 , Martin Hewitson <martin.hewit...@aei.mpg.de> wrote:
>
>> I have a table view bound to shared user defaults with a key which returns
>> an array of strings.
>> I have a button for creating a new entry. This calls a piece of code like
>> this:
>>
>>
>> NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
>> NSMutableArray *commands = [defaults
>> mutableArrayValueForKey:TECiteCommands];
>> [commands addObject:newCommand];
>> [defaults setObject:commands forKey:TECiteCommands];
>> [defaults synchronize];
>> [commandsTable reloadData];
>
>> I guess I'm abusing the use of NSUserDefaults somehow, but I don't know how.
>
>
> I've seen an array operation hang before, when 'mutableArrayValueForKey:' is
> not being used properly.
>
> It's improper because NSUserDefaults isn't MVC-compliant this for kind of
> change. A setting that's an array object (in spite of the convenience
> accessor 'arrayValueForKey:') isn't represented by an array property at all.
> (It is represented, I would imagine, by a NSData object that consists of the
> results of archiving the array object you originally specified.)
>
> You should probably do something like this instead:
>
>> NSMutableArray *commands = [[defaults arrayValueForKey:TECiteCommands]
>> mutableCopy]; // because arrayValueForKey returns an immutable object
>> [commands addObject:newCommand];
>> [defaults setObject:commands forKey:TECiteCommands];
>
> My guess is that it only ever worked because of an accidental implementation
> detail.
>
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Martin Hewitson
Albert-Einstein-Institut
Max-Planck-Institut fuer
Gravitationsphysik und Universitaet Hannover
Callinstr. 38, 30167 Hannover, Germany
Tel: +49-511-762-17121, Fax: +49-511-762-5861
E-Mail: martin.hewit...@aei.mpg.de
WWW: http://www.aei.mpg.de/~hewitson
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