Copy custom class object

Question

I have a custom class which has got some properties. And I want to copy an object of this class so I get second object with the same content.
Example:

MyCustomClass *objectName = [[MyCustomClass alloc] init];
// fill here with some properties
objectName.propertyOne = @"smth";
objectName.propertyTwo = @"smth";
// And copy my object
MyCustomClass *secontObject = [objectName copy];

Does there exist something like "copy" method?

Note: the real copy method which is already built in didn't help.

https://developer.apple.com/library/ios/documentation/general/conceptual/devpedia-cocoacore/ObjectCopying.html — pNre, Apr 13 '14 at 18:46
In order for the `copy` method to give useful results you need to implement the `copyWithZone:` method in `MyCustomClass`. That will be called by `copy`. — rmaddy, Apr 13 '14 at 18:51
possible duplicate of [the friendly documentation](https://developer.apple.com/library/mac/documentation/General/Conceptual/DevPedia-CocoaCore/ObjectCopying.html), found via [a search for "copying"](https://developer.apple.com/library/mac/search/index.php?Search=copying) in Apple's docs. — jscs, Apr 13 '14 at 18:53

score 2 · Accepted Answer · answered Apr 13 '14 at 18:51

2

There is nothing built in. The NSCopying protocol is included for this, but since it's just a protocol, you have to implement the copying logic yourself.

answered Apr 13 '14 at 18:51

Chuck

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Ok, It seems I should write this logic for every class which's objects I need to copy. Thanks. – Rendel Apr 14 '14 at 07:28

score 2 · Answer 2 · answered Apr 13 '14 at 18:56

To use copy method you first need to implement NSCopying protocol for your custom class:

@interface SomeClass : NSObject <NSCopying> 

@property (nonatomic, strong) NSString *string;
@property (nonatomic, strong) NSNumber *number;

@end


@implementation SomeClass

- (id)copyWithZone:(NSZone*)zone
{
     SomeClass *copyObject = [SomeClass new];
     copyObject.string = _string;
     copyObject.number = _number;

     return copyObject;
}

. . . . . . .

@end

score 1 · Answer 3 · edited May 23 '17 at 11:57

1

You cannot make a copy of a custom class. You'll need to implement copy logic yourself.

See How to copy an object in objective c

edited May 23 '17 at 11:57

Community

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answered Apr 13 '14 at 18:55

joels

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If you find another question that you believe answers this one, please flag the question for a moderator or vote to mark this as a duplicate rather than posting just a link. That allows solutions to a single problem to aggregate in one place, increasing their findability. – jscs Apr 13 '14 at 18:57
Thanks Josh. Will do in the future. – joels Apr 13 '14 at 19:14

Copy custom class object

3 Answers3