I tried doing this:
const void*
retainCallback(CFAllocatorRef inAlloc, const void* inValue)
{
NSObject* val = (NSObject*) inValue;
[val retain];
return val;
}
void
releaseCallback(CFAllocatorRef inAlloc, const void* inValue)
{
NSObject* val = (NSObject*) inValue;
[val release];
}
CFDictionaryKeyCallBacks
sKeyCallbacks =
{
0,
retainCallback,
releaseCallback,
NULL,
NULL,
NULL
};
CFDictionaryValueCallBacks
sValCallbacks =
{
0,
retainCallback,
releaseCallback,
NULL,
NULL,
NULL
};
- (BOOL)
application: (UIApplication*) inApp
didFinishLaunchingWithOptions: (NSDictionary*) inOptions
{
mFactoriesByLayer = (NSMutableDictionary*)
CFDictionaryCreateMutable(kCFAllocatorDefault,
3,
&sKeyCallbacks,
&sValCallbacks);
.
.
.
[mFactoriesByLayer setObject: factory forKey: factory.layer];
}
But the setObject fails.
However, since you say I can store arbitrary keys on the object, that's the
better way to go. I didn't realize one could do this.
Thanks!
On Feb 1, 2010, at 00:26:53, Roland King wrote:
> Tollfree Bridging is a little more complicated than that. They may end up
> being the same object under the covers, but even if they are, the
> NSDictionary version doesn't come with the range of options that the
> CFDictionary does. Just make a CFDictionary(), the default for it is to
> retain keys (and values) so it's actually really, really easy; I use them all
> over the place for stuff like this.
>
> If a have a non-NSDictionary compatible CFDictionary() like that by the way I
> use toll free bridging for reading values from it, but I don't use it for
> setting them, it doesn't seem to work.
>
> By the way, CALayer is a KVC compliant class so you can in fact just store a
> reference to an arbitrary object in it with
>
> [ layer setValue:value forKey:@"KeyForObjectAssociatedWithLayer" ];
>
> and save yourself a whole world of pain.
>
> Richard Penwell wrote:
>> I thought NSDictionary and CFDictionary were the same data object, that
>> whole toll free bridging...
>> An ugly hack would be to cast the pointer to a numeric type, and encode that
>> in a NSNumber... but I would feel very very ashamed of doing so.
>> On Feb 1, 2010, at 3:10 AM, Roland King wrote:
>>> Because NSDictionary requires keys to be copyable because it copies them
>>> (it's in the documentation). Use a CFDictionary() instead, you can set it
>>> up to retain the keys and do what you want.
>>>
>>> Rick Mann wrote:
>>>
>>>> I'd like to use a CALayer object as a key in a dictionary. The reason is
>>>> that when my app detects a hit in a layer, I need to quickly determine
>>>> which object I've associated with it. Since I can't store a reference to
>>>> an arbitrary object in the CALayer, a dictionary seems to be the most
>>>> expedient way to do that.
>>>> Unfortunately, I can't seem to add my layer as the key (it fails with
>>>> "-[CALayer copyWithZone:]: unrecognized selector sent to instance
>>>> 0x50132a0"). It's really pretty handy to be able to use any object as a
>>>> key, why is this not the case in Obj-C?
>>>> TIA,
>>>> Rick
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