Re: How to initialise an array class inheriting from NSArray?

[Yen-Ju Chen]

 -arrayWithObjects: is class method, and -init is instance method.
 Not sure you can mix them together.
 You probably can try:

 - (id) init
 {
   self = [super initWithObjects: ...];
   return self;
 }

 and use your NewClass in this way: NewClass *object = [[NewClass alloc] 
init];

 Since you need only two extra methods, category is really more easy.
 Simply define the extra methods like this:

 @interface NSArray (ExtraMethod)
 - (id) extraMethod;
 @end

 and implement them as:

 @implementation NSArray (ExtraMethod)
 - (id) extraMethod
 {
   /* Do something  such as */
   int count = [self count];
  /* ... */
  return self;
 }

 And use the new category as:

 #include "YourExtraMethod.h"

 NSArray *array = [NSArray array];
 [array extraMethod];

 Hope it help

 Yen-Ju

> From: Christopher Culver <crculver@users.sourceforge.net>
> To: discuss-gnustep@gnu.org
> Subject: How to initialise an array class inheriting from NSArray?
> Date: Wed, 4 Jun 2003 04:40:24 +0300
>
> I've got a class that inherits from NSArray, but don't know how to 
> initialise it. Here's how it looks:
>
> @implementation NewClass : NSArray.
>
> [...]
>
> - (id) init
> {
>        self  = [super arrayWithObjects: @"String1", @"String2", nil];
>        return self;
> }
>
> However, when I compile this, gcc reports that "NSArray doesn't respond to 
> arrayWithObjects". How then am I supposed to initalise this subclass?
>
> (And the reason this is a subclass is because I want to use it as a data 
> source for an NSTableView, for which I have to define two extra methods, 
> and this is the only way I know how at the moment. I hear something called 
> "categories" might be useful, but haven't learned about this yet).
>
> Christopher Culver
>
>
> _______________________________________________
> Discuss-gnustep mailing list
> Discuss-gnustep@gnu.org
> http://mail.gnu.org/mailman/listinfo/discuss-gnustep

_________________________________________________________________
MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*.  
http://join.msn.com/?page=features/virus