On 19 Jan 2010, at 23:06, Jens Alfke wrote:
>
> On Jan 19, 2010, at 10:46 AM, Kirk Kerekes wrote:
>
>> NSDictionary will use almost any object as a key:
>>
>> From the docs:
>> "In general, a key can be any object (provided that it conforms to the
>> NSCopying protocol...)"
>>
>> -- and if it is an immutable object, that -copy is just a -retain.
>
> Yes, but he said he wants to use a view as the key. Views are not immutable,
> and do copy themselves in response to -copy. Having a dictionary whose key
> objects are copies of your live views is not very useful. (Especially since
> the copied view will have a different hashcode from the original one, so you
> can't even look it up using the original view anymore...)
Well he could write a category to give him an object that satisfies all the
criteria e.g (written in Mail).
@interface NSView(DictionaryKey)
-(NSNumber*) dictionaryKey;
@end
@implementation NSView(DictionaryKey)
-(NSNumber*) dictionaryKey
{
return [NSNumber numberWithUnsignedLongLong: (unsigned long long) self];
}
@end
Then he could do things like:
[myDictionary setObject: foo forKey: [myView dictionaryKey]];
...
bar = [myDictionary objectForKey [myView dictionaryKey]];
The above creates a key based on the address of the NSView.
>
> —Jens_______________________________________________
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