我可以在NSArray上使用自定义类方法返回常量吗？

Question

I frequently need to refer to an array of strings (let's say team names) in multiple places. The contents of that array to not change.

To achieve this, I defined my own class, MyConstants . In the header I am defining some unrelated constant strings and numbers. In the implementation file, I made the class a singleton, and then added a class method arrayOfTeamNames .

To access the array, I use [Constants arrayOfTeamNames].

I this acceptable?

I was thinking about how NSString and NSArray themselves handle creation via class methods. If, for example, I want an empty array, I can use [NSArray array] - so presumably 'array' is a class method on NSArray.

Therefore, instead of my above implementation, should I be using a category to add '+arrayOfTeamStrings' to NSArray, instead of using my own class?

Or, alternatively, should I create my own subclass of NSArray and add the class method there?

In either case, do I need to make the class a singleton myself? Or is this not necessary?

Answer 1

In general, there can be very good uses for adding class methods to foundation classes via categories. But in this case, I would actually stick with arrayOfTeamNames being part of MyConstants . The fact that Team Names is an NSArray isn't as important as the fact that it's a constant for your application.

If the values defined in MyConstants are very diverse and unrelated, or if there are only a couple of them, then I would consider just getting rid of MyConstants as a class and using categories or even just externs, eg extern NSArray * const BPAllTeamNames .