如何生成唯一标识符？

Question

我需要生成一些永远不会重复的int值(至少在理论上).我知道有arc4random()fnc,但我不知道如何使用它与当前日期或smth :(

Answer 1

这将返回一个与MySQL中生成的UUID非常相似的唯一键.

+ (NSString *)uuid
{
    CFUUIDRef uuidRef = CFUUIDCreate(NULL);
    CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
    CFRelease(uuidRef);
    return [(NSString *)uuidStringRef autorelease];
}

ARC版:

+ (NSString *)uuid
{
    CFUUIDRef uuidRef = CFUUIDCreate(NULL);
    CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
    CFRelease(uuidRef);
    return (__bridge_transfer NSString *)uuidStringRef;
}

Answer 2

生成UUID(iOS 6或更高版本)的简单版本.

Objective-C的:

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

Swift 3+:

let uuid = UUID().uuidString

它将生成类似68753A44-4D6F-1226-9C60-0050E4C00067的内容,每次调用此功能时都是独一无二的,即使在多个设备和位置也是如此.

参考:https: //developer.apple.com/library/ios/documentation/Foundation/Reference/NSUUID_Class/Reference/Reference.html