iphone - 今天的 NSTimeInterval，时间为零(午夜)

Question

我如何计算今天的 NSTimeInterval 时分秒为零？

我知道今天的NSTimeInterval是这样的:

NSTimeInterval  today = [[NSDate date] timeIntervalSince1970];

但是我该如何重置时间呢？

Answer 1

NSDate *currentDate = [NSDate date];
NSDateComponents *currentDateComponents = [calendar components:NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit fromDate:currentDate];
NSDateComponents *currentDateToMidnight = [[NSDateComponents alloc] init];
[currentDateToMidnight setHour:-[currentDateComponents hour]];
[currentDateToMidnight setMinute:-[currentDateComponents minute]];
[currentDateToMidnight setSecond:-[currentDateComponents second]];
NSDate *midnight = [calendar dateByAddingComponents:currentDateToMidnight toDate:currentDate options:0];
NSTimeInterval todayTimeInterval = [midnight timeIntervalSince1970];