Re: Indexed Accessors for arrays

FROM : Dustin Voss
DATE : Thu Nov 25 18:30:43 2004

On 25 Nov, 2004, at 7:51 AM, Ricky Sharp wrote:

> I'm ensuring my objects are KVC compliant.  Thanks to Kevin Callahan's
> Accessorizer, this is going very smoothly.
>
> However, I'm trying to figure out what to do with the following iVar:
>
> NSString*    imageNames [IIButtonImageCount];
>
> where IIButtonImageCount is a constant (currently 6).  This
> fixed-sized array stores the names of the images to use for all states
> I allow for my buttons.  If a particular value is nil, that signals
> that the particular state doesn't have an image in which case it
> reverts to using some other state.  For example, not all my buttons
> will have "mouseover" images.
>
> But isn't it a case where I cannot create indexed accessors for
> imageNames as it isn't one of the collection classes (e.g. NSArray)?


Sure you can. The actual data structure doesn't matter, what matters is
that there is a defined set of methods the system can call. In this
case, you simply have to implement -countOfImageNames and
-objectInImageNamesAtIndex:.

> And, while I don't currently have ivars like this:
>
> float someAttribute [SomeConstant];
>
> Would that also have to be changed to say an NSArray containing
> NSNumbers?


This one is the same thing, just make sure that
-objectInSomeAttributeAtIndex: returns an NSNumber.