CODEWITHSUNDEEP
ioscore-data
Scott
Scott

Reputation: 783

Convert Managed Object to Data object

How do I convert my NSManagedObject to NSData object?

I'm new to Core Data and the Multipeer Connectivity Framework.

I need to transfer data between 2 devices via the Multipeer Connectivity Framework. I understand that I cannot simply transfer via MPC since it requires an NSData object.

Are there any third-party libraries that provides such function?

Upvotes: 3

Views: 1568

Answers (3)

Sanjay Shingarwad
Sanjay Shingarwad

Reputation: 33

You should use NSCoding protocol. Using NSKeyedAchiever you can encode your object to NSData. Again If you want decode your original object use NSKeyedUnarchiver.

@interface Test : NSManagedObject <NSCoding>
@property (nonatomic, retain) NSString *title;
@end

@implementation Test
@dynamic title;

- (id)initWithCoder:(NSCoder *)coder {
    NSEntityDescription *entity = 
    [NSEntityDescription entityForName:@"Test"  inManagedObjectContext:<YourContext>];

    self = [super initWithEntity:entity insertIntoManagedObjectContext:nil];
    NSArray * attributeNameArray = 
    [[NSArray alloc] initWithArray:self.entity.attributesByName.allKeys];

    for (NSString * attributeName in attributeNameArray) {
        [self setValue:[aDecoder decodeObjectForKey:attributeName] forKey:attributeName];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)coder {
    [coder encodeObject:self.title forKey:@"title"];
}
@end

//converting to NSData
NSData *archivedObject = [NSKeyedArchiver archivedDataWithRootObject:testObj];

//get your original object
Test *testObj = [NSKeyedUnarchiver unarchiveObjectWithData:archivedObject];

Upvotes: 0

Mundi
Mundi

Reputation: 80273

I think NSCoding is not such a good idea here. The reason is that the objects will not be the same on two different devices due to their internal managed object IDs as well as a myriad of other possible problems that can occur in unexpected syncing scenarios.

I would strongly recommend to take the trouble and convert your object into a NSDictionary type and then use the standard NSData APIs on the dictionary (or an array of dictionaries).

Upvotes: 2

Sport
Sport

Reputation: 8945

try like this You should use NSCoding protocol, then you can encode your object to NSData. Again If you want decode your original object use NSKeyedUnarchiver.

in .h 

@interface Testting : NSManagedObject<NSCoding>

and this in .m

  NSData *data=[NSKeyedArchiver archivedDataWithRootObject:hereyourObject];

//get your original object

Testting *Obj = [NSKeyedUnarchiver unarchiveObjectWithData:data];

Upvotes: 0

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