iphone - 为什么我的 NSDateFormatter 有时会返回上午或下午。与 yyyyMMddHHmmssSSS？

Question

有时我的代码会返回上午或下午。但不总是。大多数时候它只是返回我所期望的，类似于:20110815170852164

但其他时候返回:20100412010241 a.m.450

NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:@"yyyyMMddHHmmssSSS"];
NSString *dateString = [dateFormatter stringFromDate:[NSDate date]];

这可能是什么原因造成的？用户 iPhone 上的特定日期/时间国家/地区设置？我已经把这个发给了成千上万的人，大多数人不会在上午返回(这是预期的)，但其他人会。为什么？

Answer 1

您描述的问题是一个已知错误。 Check out some discussion on the problem on stackoverflow ，您可以在那里找到一些可能的解决方法。

这是 huyz 对错误的解释的摘录:

The problem comes from NSDateFormatter somehow “getting stuck” in the 12 or 24-hour time mode that the user has manually selected. So if a French user manually selects 12-hour mode, and the application requested NSDateFormatter to output time with the 24-hour format “HHmm”, it would actually receive time in a 12-hour format, e.g. “01:00 PM”, as if the application had instead requested “hhmm aa”. The reverse would happen if a US user manually selected 24-hour mode: outputting time with the 12-hour format “hhmm aa” would actually get you time in the 24-hour format instead, e.g. “17:00″.