On Nov 13, 2009, at 6:58 AM, Graham Cox wrote:
>
> On 13/11/2009, at 4:41 PM, Martin Hewitson wrote:
>
>> The point is to store an array of 'items' with a 'name' together with a
>> 'color'. And later there may be more properties of an 'item'.
>
>
> This really calls for your own 'item' class that holds all the various
> properties that you have in mind. You can then easily bind to any property,
> and the class becomes a strict "template" for the valid properties of the
> item. A dictionary is open-ended and can't be made to conform to a common
> template. You will therefore be doing a lot of extra work to force it to fit
> your design when a simple class is sufficient. Make it NSCoding compliant for
> easy archiving to NSUserDefaults.
>
Oh yes, this is a much nicer idea. Actually, the dictionary items are meant to
stand for defaults of an NSManagedObject class. I guess I can just make that
class conform to NSCoding and go from there. I'd read somewhere that it was a
bad idea to make a subclass of NSManagedObject conform to NSCoding, but I don't
recall the rational behind that. Anyway, for this very simple object (entity)
it seems like the way to go.
Again, thanks for your thoughts on this!
Martin
> KVC makes the ordinary properties of an object "look like" a kind of
> dictionary, but forcing an actual NSDictionary to stand in for an object is
> often quite painful and more hassle than it's worth just to save implementing
> a simple class, or to gain some minor functionality for free, such as
> archiving. As it stands an 'item' class with two properties shouldn't take
> very long to code - you'll be glad you did.
>
> --Graham
>
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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: [email protected]
WWW: http://www.aei.mpg.de/~hewitson
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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