Always get a unique device id in iOS 7

Question

Our iOS application is for specific users. So, we used device unique identifier for user identification. This approach works fine till iOS 6, because we are getting the same value every time.

NSString *strUniqueIdentifier = [[UIDevice currentDevice] uniqueIdentifier];

In iOS 7, the above method is returning different values and we are getting issues in user identification. iOS 7 provides the following alternate.

NSUUID *oNSUUID = [[UIDevice currentDevice] identifierForVendor];
[strApplicationUUID setString:[oNSUUID UUIDString]];

We replaced uniqueIdentifier with identifierForVendor, and created an Ad-hoc build. We then installed the build on both iOS 7 and iOS 6 devices. So far in iOS 7, we are getting the same value every time, but iOS 6 gives different values every time we delete and reinstall the app.

Answer 1

Use this little helper method to keep identifier in Keychain between install/delete sessions of app

-(NSString *)getUniqueDeviceIdentifierAsString
{
    NSString *appName=[[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString*)kCFBundleNameKey];

    NSString *strApplicationUUID = [SSKeychain passwordForService:appName account:@"incoding"];
    if (strApplicationUUID == nil)
    {
        strApplicationUUID  = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
        [SSKeychain setPassword:strApplicationUUID forService:appName account:@"incoding"];
    }

    return strApplicationUUID;
}

Add the SSKeychain library to your project, e.g. via Cocoapods with pod 'SSKeychain'