Best way to enum NSString

Question

Im digging for ways to enum objc object such as NSString, I remember there a new feature in a version of Xcode4+ which offering a new way to enum , but not clearly. Anyone know that?

Answer 1

OK, I answered myself. Guess I make a mistake.

This is the new feature I mentioned above:

typedef enum Language : NSUInteger{      ObjectiveC,      Java,       Ruby,       Python,      Erlang  }Language; 

It's just a new syntax for enum in Xcode 4.4, but I'm so foolish to think we can exchange "NSUInteger" to "NSString".

So here is the way I found that works:

http://longweekendmobile.com/2010/12/01/not-so-nasty-enums-in-objective-c/

// Place this in your .h file, outside the @interface block typedef enum {     JPG,     PNG,     GIF,     PVR } kImageType; #define kImageTypeArray @"JPEG", @"PNG", @"GIF", @"PowerVR", nil  ...  // Place this in the .m file, inside the @implementation block // A method to convert an enum to string -(NSString*) imageTypeEnumToString:(kImageType)enumVal {     NSArray *imageTypeArray = [[NSArray alloc] initWithObjects:kImageTypeArray];     return [imageTypeArray objectAtIndex:enumVal]; }  // A method to retrieve the int value from the NSArray of NSStrings -(kImageType) imageTypeStringToEnum:(NSString*)strVal {     NSArray *imageTypeArray = [[NSArray alloc] initWithObjects:kImageTypeArray];     NSUInteger n = [imageTypeArray indexOfObject:strVal];     if(n < 1) n = JPG;     return (kImageType) n; } 

FYI. The original author of the second example code created a category for enum handling. Just the thing for adding to your very own NSArray class definition.

@interface NSArray (EnumExtensions)  - (NSString*) stringWithEnum: (NSUInteger) enumVal; - (NSUInteger) enumFromString: (NSString*) strVal default: (NSUInteger) def; - (NSUInteger) enumFromString: (NSString*) strVal;  @end  @implementation NSArray (EnumExtensions)  - (NSString*) stringWithEnum: (NSUInteger) enumVal {     return [self objectAtIndex:enumVal]; }  - (NSUInteger) enumFromString: (NSString*) strVal default: (NSUInteger) def {     NSUInteger n = [self indexOfObject:strVal];     if(n == NSNotFound) n = def;     return n; }  - (NSUInteger) enumFromString: (NSString*) strVal {     return [self enumFromString:strVal default:0]; }  @end 

Answer 2

Alternative way to use struct:

extern const struct AMPlayerStateReadable {     __unsafe_unretained NSString *ready;     __unsafe_unretained NSString *completed;     __unsafe_unretained NSString *playing;     __unsafe_unretained NSString *paused;     __unsafe_unretained NSString *broken; } AMPlayerState;  const struct AMPlayerStateReadable AMPlayerState = {     .ready = @"READY",     .completed = @"COMPLETE",     .playing = @"PLAYING",     .paused = @"PAUSED",     .broken = @"BROKEN" }; 

Then you can use like this:

NSString *status = AMPlayerState.ready; 

Easy to use, readable. Would be nice if someone update/edit answer with advantages/disadvantages of this approach.