Question

我使用NSDateIntervalFormatter格式化一系列小时数。他们总是在同一天，所以我不想显示日期。在美国英语区域，它们看起来像晚上9点到晚上10点。

当时间跨越午夜时出现问题。然后，结束日期在技术上在第二天，NSDateIntervalFormatter打印日期，即使其dateStyle设置为NSDateFormatterNoStyle：

NSDateComponents *comps = [[NSDateComponents alloc] init];
comps.year = 2015;
comps.month = 5;
comps.day = 12;
comps.hour = 21;

NSDate *startDate = [[NSCalendar currentCalendar] dateFromComponents:comps];

// next day, at midnight
comps.day = comps.day + 1;
comps.hour = 0;
NSDate *endDate = [[NSCalendar currentCalendar] dateFromComponents:comps];

NSDateIntervalFormatter *formatter = [[NSDateIntervalFormatter alloc] init];
formatter.timeZone = [NSTimeZone localTimeZone];

formatter.dateStyle = NSDateFormatterNoStyle;
formatter.timeStyle = NSDateFormatterShortStyle;

NSString *string = [formatter stringFromDate:startDate toDate:endDate];
NSLog(@"%@", string);
// expected: 9:00 PM - 12:00 AM
// actual: 5/12/2015, 9:00 PM - 5/13/2015, 12:00 AM

有没有办法让它始终隐藏日期，而不必单独格式化两个日期并用破折号加入它们？

Answer 1

If you eliminate the Y/M/D from the date components it works as desired:

@"string"

Also interesting is if comps.day + 1 is removed, it shows:

NSDateComponents *comps = [[NSDateComponents alloc] init];
//    comps.year = 2015;
//    comps.month = 5;
//    comps.day = 12;
comps.hour = 21;

NSDate *startDate = [[NSCalendar currentCalendar] dateFromComponents:comps];

// next day, at midnight
comps.day = comps.day + 1;
comps.hour = 24;
NSDate *endDate = [[NSCalendar currentCalendar] dateFromComponents:comps];

NSDateIntervalFormatter *formatter = [[NSDateIntervalFormatter alloc] init];
formatter.timeZone = [NSTimeZone localTimeZone];

formatter.dateStyle = NSDateFormatterNoStyle;
formatter.timeStyle = NSDateFormatterShortStyle;

NSString *string = [formatter stringFromDate:startDate toDate:endDate];
// string = 9:00 PM - 12:00 AM

Which to me makes no sense.... 1/3?!

Update: It appears to be have the correct result only when endDate is one day before startDate. It does not if it's more than a day off. This feels like undefined territory, not working as desired.

即使dateStyle设置为NSDateFormatterNoStyle，NSDateIntervalFormatter也会打印日期

1 个答案: