iphone - 如何生成唯一标识符？

Question

我需要生成一些永远不会重复(至少在理论上)的 int 值。我知道有 arc4random() fnc 但我不确定如何将它与当前日期或 smth 一起使用 :(

Answer 1

这会返回一个与 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 版本:

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