How to use NSCoder

Question

I am developing iphone application.

I use NSCoder.

MyApplication.h

#define ITEMS_KEY @\"items\"
#define CATEGORIES_KEY @\"categories\"


#imp         


        

Answer 1

I wrote a helper function for using NSCoding. It's a part of VSCore Library. Check it out here:

@interface QuickCoding : NSObject

+ (void)quickEncode:(NSObject*)object withEncoder:(NSCoder*)encoder;
+ (void)quickDecode:(NSObject*)object withDecoder:(NSCoder*)decoder;

@end

And the .m file:

#import "QuickCoding.h"
#import "ReflectionHelper.h"

#define QUICK_CODING_HASH   @"h4"

@implementation QuickCoding

+ (void)quickEncode:(NSObject*)object withEncoder:(NSCoder *)encoder{
    NSArray *codingKeys = [ReflectionHelper fieldsList:[object class]];
    NSUInteger hash = [[codingKeys componentsJoinedByString:@""] hash];
    [encoder encodeObject:@(hash) forKey:QUICK_CODING_HASH];

    [codingKeys enumerateObjectsUsingBlock:^(NSString *key, __unused NSUInteger idx, __unused BOOL *stop) {
        id val = [object valueForKey:key];
        if ([val conformsToProtocol:@protocol(NSCoding)]){
            [encoder encodeObject:val forKey:key];
        }
    }];
}

+ (void)quickDecode:(NSObject*)object withDecoder:(NSCoder *)decoder{
    NSArray *codingKeys = [ReflectionHelper fieldsList:[object class]];
    NSUInteger hash = [[codingKeys componentsJoinedByString:@""] hash];
    NSUInteger decodedHash = [[decoder decodeObjectForKey:QUICK_CODING_HASH] unsignedIntegerValue];
    BOOL equalHash = hash == decodedHash;

    [codingKeys enumerateObjectsUsingBlock:^(NSString *key, __unused NSUInteger idx, __unused BOOL *stop) {
        id val = [decoder decodeObjectForKey:key];
        if (equalHash || val){
            [object setValue:val forKey:key];
        }
    }];
}

@end

Full code is here: https://github.com/voipswitch/VSCore/tree/master/VSCore/Storage