How to generate UUID in ios

Question

How to get a UUID in objective c, like in Java UUID is used to generate unique random numbers which represents 128 bit value.

possible duplicate of [How to create a GUID/UUID using the iPhone SDK](http://stackoverflow.com/questions/427180/how-to-create-a-guid-uuid-using-the-iphone-sdk) — Basil Bourque, May 21 '14 at 23:31

score 176 · Accepted Answer · edited Nov 12 '19 at 19:44

Try:

CFUUIDRef udid = CFUUIDCreate(NULL);
NSString *udidString = (NSString *) CFUUIDCreateString(NULL, udid);

UPDATE:

As of iOS 6, there is an easier way to generate UUID. And as usual, there are multiple ways to do it:

Create a UUID string:

NSString *uuid = [[NSUUID UUID] UUIDString];

Create a UUID:

[NSUUID UUID]; // which is the same as..
[[NSUUID] alloc] init];

Creates an object of type NSConcreteUUID and can be easily casted to NSString, and looks like this: BE5BA3D0-971C-4418-9ECF-E2D1ABCB66BE

NOTE from the Documentation:

Note: The NSUUID class is not toll-free bridged with CoreFoundation’s CFUUIDRef. Use UUID strings to convert between CFUUID and NSUUID, if needed. Two NSUUID objects are not guaranteed to be comparable by pointer value (as CFUUIDRef is); use isEqual: to compare two NSUUID instances.

If you are using iOS 6, you can use NSUUID: NSString * uuid = [[NSUUID UUID] UUIDString]; — Eli Burke, Jul 25 '13 at 12:58
on line 1, `CFUUIDRef udid` should probably be `CFUUIDRef uuid` to avoid potential confusion of UDID (Unique Device Identifier) with UUID (Universally Unique Identifier) — CgodLEY, Apr 23 '14 at 15:47

score 10 · Answer 2 · edited Mar 17 '22 at 15:59

10

Swift version of Raptor's answer:

let uuid = UUID().uuidString

edited Mar 17 '22 at 15:59

timbre timbre

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answered Oct 08 '15 at 23:29

3lil636wm

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score 6 · Answer 3 · edited Aug 11 '17 at 08:01

6

+ (NSString *)uniqueFileName
{
    CFUUIDRef theUniqueString = CFUUIDCreate(NULL);
    CFStringRef string = CFUUIDCreateString(NULL, theUniqueString);
    CFRelease(theUniqueString);
    return [(NSString *)string autorelease];
}

edited Aug 11 '17 at 08:01

Pang

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answered Jan 16 '13 at 06:21

Bergasms

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You really shouldn't just leave code without explanation, no matter how straightforward it is – Allison Jun 04 '14 at 17:26
Errr, not sure why you selected my particular reply to comment on a year and a half later XD. – Bergasms Jun 05 '14 at 01:23
I didn't realize it was 1.5 years old.. Oh well, it does work nicely though.. :) – Allison Jun 05 '14 at 02:54

score 3 · Answer 4 · answered Jan 16 '13 at 06:30

-(NSString*) myUUID()
{
    CFUUIDRef newUniqueID = CFUUIDCreate(kCFAllocatorDefault);
    CFStringRef newUniqueIDString = CFUUIDCreateString(kCFAllocatorDefault, newUniqueID);
    NSString *guid = (__bridge NSString *)newUniqueIDString;
    CFRelease(newUniqueIDString);
    CFRelease(newUniqueID);
    return([guid lowercaseString]);
}

score 1 · Answer 5 · answered Aug 06 '13 at 19:19

1

you can use CFUUID for iOS 5 or lower version and NSUUID for iOS 6 and 7. for making it more secure you can store your UUID in keychain

answered Aug 06 '13 at 19:19

Veeru Sharma

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score 0 · Answer 6 · answered Jan 30 '17 at 13:56

0

- (NSString*)generateGUID{
    CFUUIDRef theUUID = CFUUIDCreate(NULL);
    CFStringRef string = CFUUIDCreateString(NULL, theUUID);
    CFRelease(theUUID);
    return [NSString stringWithFormat:@"%@", string];
}

answered Jan 30 '17 at 13:56

Sargis

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Code-only answers aren't useful for the community. Please look at [answer] – JimHawkins Jan 30 '17 at 15:34

score -3 · Answer 7 · answered May 11 '20 at 10:55

-3

For Swift 5.0, Use this,

    let uuidRef = CFUUIDCreate(nil)
    let uuidStringRef = CFUUIDCreateString(nil, uuidRef)
    let uuid = uuidStringRef as String? ?? ""

answered May 11 '20 at 10:55

Sureshkumar Linganathan

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How to generate UUID in ios

7 Answers7

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