Question

我对KVO有一个简单的问题。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。我希望以下内容可以帮助任何未来的开发人员。

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

[Images setObject:someObject forKey:someIndex];

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

Answer 1

只是为了确保问题得到解答。信用转到@DoubleDunk

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

    [Images setObject:someObject forKey:someIndex];

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

NSMutableDictionary添加和删除KVO

1 个答案: