NSMutableDictionary是否通过“ setValue：forKey：”对我放入的对象保持强烈引用？

Question

According to Apple's documentation, if I add an object to an NSMutableDictionary via the setObject:forKey: method, the dictionary will keep a strong reference to it.

But what about the setValue:forKey: method? The documentation doesn't say anything about the kind of reference to the object added via this method. Is it the same as the other one? Does the dictionary keep a strong reference to the object added via this method as well?

Answer 1

NSMutableDictionary （和NSMutableArray ）保持对添加到其中的任何对象的强引用，无论它如何添加。

Answer 2

NSMutableArray and NSArray keep strong references to objects they contain. These objects are either added using the literal constructor @[myObject, myObject2, ...] , the initializers of NSArray , or the add/insert methods of NSMutableArray .

If you're looking for key/value storage like a map, you want to use NSDictionary / NSMutableDictionary instead. The setValue:forKey: method you're talking about is for key-value coding compliance, which is different.

Additionally, NSDictionary and NSMutableDictionary keep strong references to value objects, and keep copy references to keys (which must comply to the NSCopying protocol).