ios – NSMutableDictionary添加和删除KVO

我有一个关于KVO的快速问题.我理解,对于NSArray,如果需要观察添加,您可以执行以下操作.

NSIndexSet* set = [NSIndexSet indexSetWithIndex:[someIndex IntegerValue]];
            [self willChange:NSKeyValueChangeInsertion valuesATindexes:set forKey:@"theArrayName"];
                // add the objects at the specified indexes here
            [self didChange:NSKeyValueChangeInsertion valuesATindexes:set forKey:@"theArrayName"];

注册观察后,您将获得一个更改字典,其中包含已更改的索引.

但是,我不明白如何观察NSMutableDictionary的新对象添加.有没有办法观察对象的添加/删除？

谢谢,

[编辑]
我找到了满足当前需求的解决方案.我希望以下内容有助于未来的开发人员.

[self willChangeValueForKey:@"someDictionary" withSetMutation:NSKeyValueUnionSetMutation usingObjects:[NSSet setWithObject:someObject]];

[Images setObject:someObject forKey:someIndex];

[self didChangeValueForKey:@"someDictionary" withSetMutation:NSKeyValueUnionSetMutation usingObjects:[NSSet setWithObject:someObject]];

[self willChangeValueForKey:@"someDictionary" withSetMutation:NSKeyValueUnionSetMutation usingObjects:[NSSet setWithObject:someObject]];

    [Images setObject:someObject forKey:someIndex];

    [self didChangeValueForKey:@"someDictionary" withSetMutation:NSKeyValueUnionSetMutation usingObjects:[NSSet setWithObject:someObject]];