Re: KVO question
Re: KVO question
- Subject: Re: KVO question
- From: Daniel Stenmark <email@hidden>
- Date: Wed, 18 Nov 2015 01:36:57 +0000
- Thread-topic: KVO question
It seems like it *should* work. Are you sure you don’t have a typo in your addObserver: method? Considering that you’re using the dictionary’s property setter, keyPathsForValuesAffecting<Key> shouldn’t even be necessary. When I apply KVO, I try to mitigate the potential unsafely of key paths strings by using NSStringFromSelector() whenever possible.
[self.foo addObserver:self forKeyPath:NSStringFromSelector(@selector(bar)) options:NSKeyValueObservingOptionNew context:NULL];
Dan
On Nov 17, 2015, at 5:18 PM, Graham Cox <email@hidden<mailto:email@hidden>> wrote:
I’m using KVO to observe a bunch of properties.
Most of these properties are split out into simple things that set a single value, but internal to my object, some end up setting a common dictionary of attributes, which is also a property.
I KVO observe both the simple properties and the common dictionary property. Mostly this is working, but when code directly sets the dictionary property, the other properties don’t trigger their observers, even though I’m implementing the +keyPathsForValuesAffecting<property>, which I believe should cause the additional triggering. Have I understood that right?
Here’s the kind of code I have:
@property (retain) id<NSObject> thingy;
@property (retain) NSDicitonary* dictionaryOfThings;
@implementation
- (void) setThingy:(is<NSObject> thing
{
NSMutableDictionary* temp = [self.dictionaryOfThings mutableCopy];
[temp setObject:thing forKey:kThingKey];
self.dictionaryOfThings = temp;
}
- (id<NSObject>) thingy
{
return [self.dictionaryOfThings objectForKey:kThingKey];
}
+ (NSSet*) keyPathsForValuesAffectingThingy
{
return [NSSet setWithObject:@“dictionaryOfThings”];
}
So what I want (expect?) is that is code sets -dictionaryOfThings directly, an observer of ‘thingy’ will be triggered. Is that right?
—Graham
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