找出值是否来自JSON是布尔值（true / false）

Question

I'm coding a category on NSManagedObject so it can populates its attributes itself from a NSDictionnary I have from a JSON (via NSJSONSerialization)

My problem is: if the original value is true or false, it is converted to NSNumber, but I want to insert it in the managed object as a BOOL (I'm aware of boolValue) if, and only if it was originally a BOOL and not a number. So far, my related code is :

if ([value isKindOfClass:[NSNumber class]])
        {
            if (NSClassFromString(@"__NSCFBoolean") && [value isKindOfClass:NSClassFromString(@"__NSCFBoolean")]) {
                [self setValue:[NSNumber numberWithBool:[value boolValue]] forKey:key];
            } else if (NSClassFromString(@"NSCFBoolean") && [value isKindOfClass:NSClassFromString(@"NSCFBoolean")]) {
                [self setValue:[NSNumber numberWithBool:[value boolValue]] forKey:key];
            } else {
                [self setValue:value forKey:key];
            }
        }

I get the error :

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key myJsonOriginalKeyName

Again, my managed object has a boolean attribute for the corresponding key when it's value id true/false in the original JSON How can I automatically determine if I should convert value to a BOOL or NSNumber

Answer 1

I am doing this right now in my app, its sort of - well - not completely sanctioned, but it seems to work just fine using NSJSONSerialization in iOS7:

if(strcmp([num objCType], "c") == 0) {
   // its a boolean
   ...

The caveat us that Apple says in the Class Description that you cannot count on this to be consistent. That said, if NSJSONSerialization is only using a method to convert bools that results in this type, it probably won't change any time soon.