Objective-C: how to group a series of string constants?

Question

I defined a series of string constants like below, in macro way,

#define EXT_RESULT_APPID  @\"appid\"
#define EXT_RESULT_ERROR_CODE  @\"errorcode\"
#define         


        

Answer 1

Here's one approach:

MONExtResult.h

// add __unsafe_unretained if compiling for ARC
struct MONExtResultStruct {
    NSString * const AppID;
    NSString * const ErrorCode;
    NSString * const Progress;
};

extern const struct MONExtResultStruct MONExtResult;

MONExtResult.m

const struct MONExtResultStruct MONExtResult = {
    .AppID = @"appid",
    .ErrorCode = @"errorcode",
    .Progress = @"progress"
};

In use:

NSString * str = MONExtResult.AppID;