下面的代码有助于获得UDID:

        udid = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
        NSLog(@"UDID : %@", udid);

如果用户卸载和重新安装应用程序，CFUUIDCreate创建的UUID是唯一的:你每次都会得到一个新的UUID。

但你可能希望它不是唯一的，即它应该保持不变，当用户卸载和重新安装应用程序。这需要一些努力，因为最可靠的每个设备标识符似乎是MAC地址。您可以查询MAC并使用它作为UUID。

编辑:当然，总是需要查询同一接口的MAC。我想最好的选择是en0。MAC一直存在，即使接口没有IP/ down。

编辑2:正如其他人指出的那样，自iOS 6以来首选的解决方案是-[UIDevice identifierForVendor]。在大多数情况下，你应该可以使用它来替换旧的-[UIDevice uniqueIdentifier](但是当应用程序第一次启动时创建的UUID似乎是苹果想要你使用的)。

编辑3:所以这个重点不会在评论噪音中丢失:不要使用MAC作为UUID，使用MAC创建哈希。哈希每次都会创建相同的结果，即使是在重新安装和应用程序之间(如果哈希以相同的方式完成)。不管怎样，现在(2013年)这已经没有必要了，除非你在iOS < 6.0上需要一个“稳定的”设备标识符。

编辑4:在iOS 7中，苹果现在在查询MAC时总是返回一个固定值，以专门阻止MAC作为ID方案的基础。所以你现在应该使用-[UIDevice identifierForVendor]或者创建一个每个安装的UUID。

可以帮助: 使用下面的代码，它将永远是唯一的，除非你擦除(格式)你的设备。

objective - c:

选项1:这将在每次安装时更改

UIDevice *uuid = [NSUUID UUID].UUIDString;

选项2:这将是唯一的每个供应商/开发者苹果帐户

UIDevice *myDevice = [UIDevice currentDevice];
NSString *uuid = [[myDevice identifierForVendor] UUIDString];

斯威夫特5。X:

选项1:这将在每次安装时更改

let uuid = UUID().uuidString

选项2:这将是唯一的每个供应商/开发者苹果帐户

let myDevice = UIDevice.current
let uuid = myDevice.identifierForVendor?.uuidString

使用上面提到的SSKeychain和代码。下面是复制/粘贴(添加SSKeychain模块)的代码:

+(NSString *) getUUID {

//Use the bundle name as the App identifier. No need to get the localized version.

NSString *Appname = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"];    

//Check if we have UUID already

NSString *retrieveuuid = [SSKeychain passwordForService:Appname account:@"user"];

if (retrieveuuid == NULL)
{

    //Create new key for this app/device

    CFUUIDRef newUniqueId = CFUUIDCreate(kCFAllocatorDefault);

    retrieveuuid = (__bridge_transfer NSString*)CFUUIDCreateString(kCFAllocatorDefault, newUniqueId);

    CFRelease(newUniqueId);

    //Save key to Keychain
    [SSKeychain setPassword:retrieveuuid forService:Appname account:@"user"];
}

return retrieveuuid;

}

如果有人在寻找替代方案时偶然发现了这个问题。我在IDManager课上就采用了这种方法， 这是不同解的集合。KeyChainUtil是一个从keychain读取的包装器。 您还可以使用散列MAC地址作为一种唯一ID。

/*  Apple confirmed this bug in their system in response to a Technical Support Incident 
    request. They said that identifierForVendor and advertisingIdentifier sometimes 
    returning all zeros can be seen both in development builds and apps downloaded over the 
    air from the App Store. They have no work around and can't say when the problem will be fixed. */
#define kBuggyASIID             @"00000000-0000-0000-0000-000000000000"

+ (NSString *) getUniqueID {
    if (NSClassFromString(@"ASIdentifierManager")) {
        NSString * asiID = [[[ASIdentifierManager sharedManager] advertisingIdentifier] UUIDString];
        if ([asiID compare:kBuggyASIID] == NSOrderedSame) {
            NSLog(@"Error: This device return buggy advertisingIdentifier.");
            return [IDManager getUniqueUUID];
        } else {
            return asiID;
        }

    } else {
        return [IDManager getUniqueUUID];
    }
}


+ (NSString *) getUniqueUUID {
    NSError * error;
    NSString * uuid = [KeychainUtils getPasswordForUsername:kBuyassUser andServiceName:kIdOgBetilngService error:&error];
    if (error) {
        NSLog(@"Error geting unique UUID for this device! %@", [error localizedDescription]);
        return nil;
    }
    if (!uuid) {
        DLog(@"No UUID found. Creating a new one.");
        uuid = [IDManager GetUUID];
        uuid = [Util md5String:uuid];
        [KeychainUtils storeUsername:USER_NAME andPassword:uuid forServiceName:SERVICE_NAME updateExisting:YES error:&error];
        if (error) {
            NSLog(@"Error getting unique UUID for this device! %@", [error localizedDescription]);
            return nil;
        }
    }
    return uuid;
}

/* NSUUID is after iOS 6. */
+ (NSString *)GetUUID
{
    CFUUIDRef theUUID = CFUUIDCreate(NULL);
    CFStringRef string = CFUUIDCreateString(NULL, theUUID);
    CFRelease(theUUID);
    return [(NSString *)string autorelease];
}

#pragma mark - MAC address
// Return the local MAC addy
// Courtesy of FreeBSD hackers email list
// Last fallback for unique identifier
+ (NSString *) getMACAddress
{
    int                 mib[6];
    size_t              len;
    char                *buf;
    unsigned char       *ptr;
    struct if_msghdr    *ifm;
    struct sockaddr_dl  *sdl;

    mib[0] = CTL_NET;
    mib[1] = AF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_LINK;
    mib[4] = NET_RT_IFLIST;

    if ((mib[5] = if_nametoindex("en0")) == 0) {
        printf("Error: if_nametoindex error\n");
        return NULL;
    }

    if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 1\n");
        return NULL;
    }

    if ((buf = malloc(len)) == NULL) {
        printf("Error: Memory allocation error\n");
        return NULL;
    }

    if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 2\n");
        free(buf); // Thanks, Remy "Psy" Demerest
        return NULL;
    }

    ifm = (struct if_msghdr *)buf;
    sdl = (struct sockaddr_dl *)(ifm + 1);
    ptr = (unsigned char *)LLADDR(sdl);
    NSString *outstring = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];

    free(buf);
    return outstring;
}

+ (NSString *) getHashedMACAddress
{
    NSString * mac = [IDManager getMACAddress];
    return [Util md5String:mac];
}

+ (NSString *)md5String:(NSString *)plainText
{
    if(plainText == nil || [plainText length] == 0)
        return nil;

    const char *value = [plainText UTF8String];
    unsigned char outputBuffer[CC_MD5_DIGEST_LENGTH];
    CC_MD5(value, strlen(value), outputBuffer);

    NSMutableString *outputString = [[NSMutableString alloc] initWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    for(NSInteger count = 0; count < CC_MD5_DIGEST_LENGTH; count++){
        [outputString appendFormat:@"%02x",outputBuffer[count]];
    }
    NSString * retString = [NSString stringWithString:outputString];
    [outputString release];
    return retString;
}

这是我用来获取iOS 5和iOS 6,7的ID的代码:

- (NSString *) advertisingIdentifier
{
    if (!NSClassFromString(@"ASIdentifierManager")) {
        SEL selector = NSSelectorFromString(@"uniqueIdentifier");
        if ([[UIDevice currentDevice] respondsToSelector:selector]) {
            return [[UIDevice currentDevice] performSelector:selector];
        }
    }
    return [[[ASIdentifierManager sharedManager] advertisingIdentifier] UUIDString];
}