How to limit visibility of enum values in Objective C?

问题

In Objective C, when you define an enum, all of the enum values are visible everywhere and clog the global namespace.

I would like to make it Java-style and enforce that enums are only accessible thru the enum type name, e.g. with

typedef enum
{
MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY, NUM_OF
} Day;

I want to make sure that simply calling MONDAY produces compilation error or at least warning, and the only way to access the enum value were something like Day.MONDAY or Day::MONDAY or [Day MONDAY] or...

In Java I either use Enums or Interfaces, but is this doable in Objective-C?

If not, then I'd have to name all enums like this: DAY_MONDAY, DAY_TUESDAY... to make them easier to seach in auto-completion pop-up.

回答1:

It's just a workaround, but you can create a custom interface with a number of class methods (so that there's no need to create an instance), where each method represent a constant.

This way constants will be accessible only as you asked (ie. Day.MONDAY or [Day MONDAY]).

来源：https://stackoverflow.com/questions/7388997/how-to-limit-visibility-of-enum-values-in-objective-c