NSArray 中包含的模型上的 KVO
我想观察 NSArray 中包含的模型的属性。我无法使用“arrayOfModels.property”的 keyPath，因为 NSArray 会抛出异常 相反
- (void)addObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context;
，文档说要使用
- (void)addObserver:(NSObject *)observer toObjectsAtIndexes:(NSIndexSet *)indexes forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context;
So 这是否意味着我还必须监听“arrayOfModels”本身，以便当其元素发生变化时，我可以从旧元素中删除侦听器并将它们附加到新元素吗？我希望 KVO 足够出色，能够以某种方式为我解决这个问题......
I would like to observe a property on models contained in an NSArray. I can't use a keyPath of "arrayOfModels.property", because NSArray throws an exception on
- (void)addObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context;
Instead, the docs say to use
- (void)addObserver:(NSObject *)observer toObjectsAtIndexes:(NSIndexSet *)indexes forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context;
So does that mean I'd also have to listen to "arrayOfModels" itself, so that when its elements change, I can remove listeners from the old elements and attach them to the new elements? I was hoping KVO would be awesome enough to take care of this for me somehow...
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似乎没有内置的方法可以做到这一点，所以我只是删除旧的侦听器并在数组成员资格更改时添加新的侦听器。
Doesn't seem like there's a built-in way to do this, so I'm just removing old listeners and adding new ones when the array membership changes.