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];
}

给你一个小技巧:

/**
 @method uniqueDeviceIdentifier
 @abstract A unique device identifier is a hash value composed from various hardware identifiers such
 as the device’s serial number. It is guaranteed to be unique for every device but cannot 
 be tied to a user account. [UIDevice Class Reference]
 @return An 1-way hashed identifier unique to this device.
 */
+ (NSString *)uniqueDeviceIdentifier {      
    NSString *systemId = nil;
    // We collect it as long as it is available along with a randomly generated ID.
    // This way, when this becomes unavailable we can map existing users so the
    // new vs returning counts do not break.
    if (([[[UIDevice currentDevice] systemVersion] floatValue] < 6.0f)) {
        SEL udidSelector = NSSelectorFromString(@"uniqueIdentifier");
        if ([[UIDevice currentDevice] respondsToSelector:udidSelector]) {
            systemId = [[UIDevice currentDevice] performSelector:udidSelector];
        }
    }
    else {
        systemId = [NSUUID UUID];
    }
    return systemId;
}

虽然不完美，但却是UDID的最佳和最接近的替代品之一(在Swift中使用iOS 8.1和Xcode 6.1):

生成一个随机UUID

let strUUID: String = NSUUID().UUIDString

并使用KeychainWrapper库:

给keychain添加一个字符串值:

let saveSuccessful: Bool = KeychainWrapper.setString("Some String", forKey: "myKey")

从keychain中检索字符串值:

let retrievedString: String? = KeychainWrapper.stringForKey("myKey")

从keychain中删除一个字符串值:

let removeSuccessful: Bool = KeychainWrapper.removeObjectForKey("myKey")

该解决方案使用了keychain，因此存储在keychain中的记录将被持久化，即使在应用程序卸载和重新安装之后。删除该记录的唯一方法是重置设备的所有内容和设置。这就是为什么我提到这个替代方案并不完美，但仍然是iOS 8.1上使用Swift替代UDID的最佳方案之一。

也许你可以用:

[UIDevice currentDevice].identifierForVendor.UUIDString

苹果的文档对identifierforvendor的描述如下:

对于运行在同一设备上的来自同一供应商的应用程序，此属性的值是相同的。对于同一设备上来自不同供应商的应用程序，以及不同设备上的应用程序，无论供应商如何，都会返回不同的值。

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

我们可以在ios7中使用identifierForVendor，

-(NSString*)uniqueIDForDevice
{
    NSString* uniqueIdentifier = nil;
    if( [UIDevice instancesRespondToSelector:@selector(identifierForVendor)] ) { // >=iOS 7
        uniqueIdentifier = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
    } else { //<=iOS6, Use UDID of Device       
            CFUUIDRef uuid = CFUUIDCreate(NULL);
            //uniqueIdentifier = ( NSString*)CFUUIDCreateString(NULL, uuid);- for non- ARC
            uniqueIdentifier = ( NSString*)CFBridgingRelease(CFUUIDCreateString(NULL, uuid));// for ARC
            CFRelease(uuid);
         }
    }
return uniqueIdentifier;
}

——重要提示——

UDID和identifierForVendor是不同的:——

1.) On uninstalling  and reinstalling the app identifierForVendor will change.

2.) The value of identifierForVendor remains the same for all the apps installed from the same vendor on the device.

3.) The value of identifierForVendor also changes for all the apps if any of the app (from same vendor) is reinstalled.