为什么我输出错误的时间与正确的时区？

Question

为什么我得到这个输出时间:

2013-01-12 18:24:37.783代码测试[10328:c07] 0001-01-01 17:12:52 +0000

当我运行此代码时:

NSCalendar *calendar = [NSCalendar currentCalendar];
calendar.timeZone = [NSTimeZone localTimeZone];

NSDateComponents *components = [calendar components:NSHourCalendarUnit fromDate:[NSDate date]];
components.hour   = 17;
components.minute = 47;
components.second = 0;

NSDate *fire = [calendar dateFromComponents:components];
NSLog(@"%@", fire);

我尝试过默认时区,系统时区.它总是给我一个不同的分钟和秒的输出!加错了日期0001-01-01 !!!! 知道为什么吗？

附加测试:

运行此代码时:

NSCalendar *calendar = [NSCalendar currentCalendar];
calendar.timeZone = [NSTimeZone localTimeZone];
NSDateComponents *components = [calendar components:NSHourCalendarUnit fromDate:[NSDate date]];
components.hour   = (components.hour + 1) % 24;
components.minute = 0;
components.second = 0;
NSDate *fire = [calendar dateFromComponents:components];
NSLog(@"%@", fire);

它给了我这个输出:

2013-01-12 18:41:41.552代码测试[10648:c07] 0001-01-01 18:25:52 +0000

2013-01-12 18:42:16.274代码测试[10648:c07] 0001-01-01 18:25:52 +0000

2013-01-12 18:42:30.310代码测试[10648:c07] 0001-01-01 18:25:52 +0000

Answer 1

你正在调整年,月,日组件.

做:

NSDateComponents *components = [calendar components:NSUIntegerMax fromDate:[NSDate date]];

现在,这应该给你正确的日期.

旁注:由于NSCalendarUnit是一个bitfield typedef NSUInteger,我传入NSUIntegerMax以检索所有可能的日历单位.这样我就不必有大量的按位OR语句.