Question

I have an array of integers in my core data model. It is set up as a Transformable.

The JSON I get back from the server gives me this list of numbers in the following format:

{ "numbers": [10, 3, 2], "name": "John Smith" }

I configure my object mapping as follows:

[dataMapping mapKeyPath:@"numbers" toAttribute:@"numberList"];
[dataMapping mapKeyPath:@"name" toAttribute:@"fullName"];

No problem with fullName which is a String.

However, numberList remains null after the object has been loaded (all the regular parameters get loaded fine). I have looked around on the web but am not sure what to look for.

Any ideas?

Answer 1

This sounds like a problem with your value transformer. Try this one and tell me if it works or not. This is ARC code.

.h

@interface NSArrayValueTransformer : NSValueTransformer

@end

.m

#import "NSArrayValueTransformer.h"

@implementation NSArrayValueTransformer

+ (BOOL) allowsReverseTransformation {
    return YES;
}

+ (Class) transformedValueClass {
    return [NSData class];
}

- (id) transformedValue:(id)value {
    if( !value ) 
        return nil;

    if( [value isKindOfClass: [NSData class]] )
        return value;

    return [NSKeyedArchiver archivedDataWithRootObject: value];
}

- (id) reverseTransformedValue:(id)value {
    return [[NSKeyedUnarchiver unarchiveObjectWithData: value] mutableCopy];
}

@end