ios - 仅使用时间按日期对数组进行排序？

我目前正在使用属性 startTime 对一组对象进行排序，但是我意识到它是按日期和时间排序的。

因此，如果我添加一个对象并将时间设置为比预制对象更早的时间，如果它在一天后制作，它将始终列在另一个之后。有道理？

所以可以说我的 NSDate 是星期二 25 日下午 6:02。我想刮掉星期二的第 26 位，只按时间排序，这一天对我来说无关紧要。我怎样才能做到这一点？

谢谢。

P.S 这是我目前对我的对象进行排序的方式:

NSSet *tasks = [self.routine task];
    NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"startTime" ascending:YES];
    NSArray *sorted = [[tasks allObjects] sortedArrayUsingDescriptors:[NSArray arrayWithObject:sort]];

最佳答案

在 NSDate 上创建一个类别，该类别返回自当前日历和时区的一天开始以来的时间间隔，然后使用该时间间隔进行排序。

@interface NSDate (CBVAdditions)

- (NSTimeInterval)cbvTimeIntervalSinceStartOfDay;

@end

@implementation NSDate (CBVAdditions)

- (NSTimeInterval)cbvTimeIntervalSinceStartOfDay
{
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSTimeZone *timeZone = [NSTimeZone defaultTimeZone];
    NSDateComponents *dateComponents = [calendar components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:self];
    [dateComponents setCalendar:calendar];
    [dateComponents setTimeZone:timeZone];
    NSInteger hoursComponent = dateComponents.hour * 3600;
    NSInteger minutesComponent = dateComponents.minute * 60;
    double secondsComponent = dateComponents.second;
    NSTimeInterval toReturn = hoursComponent + minutesComponent + secondsComponent;
    return toReturn;
}

@end

然后，您可以使用 NSSortDescriptor 和 @"dateProperty.cbvTimeIntervalSinceStartOfDay" 之类的键来进行实际排序。例如，我展示了 Event 类，以及一些完成排序的代码。

@interface Event : NSObject

@property (nonatomic, strong) NSString *name;
@property (nonatomic, strong) NSDate *eventDate;

@end

@implementation Event

- (NSString *)description
{
    NSString *desc = [NSString stringWithFormat:@"%@, name = %@, eventDate = %@",[super description], self.name, [self.eventDate descriptionWithLocale:[NSLocale currentLocale]]];
    return desc;
}
@end

...

Event *e1 = [Event new];
e1.eventDate = [NSDate date];
e1.name = @"e1";
Event *e2 = [Event new];
e2.eventDate = [NSDate dateWithTimeIntervalSinceNow:(-1 * 22 * 3600)];
e2.name = @"e2";
Event *e3 = [Event new];
e3.eventDate = [NSDate dateWithTimeIntervalSinceNow:3600];
e3.name = @"e3";

NSArray *events = @[e1,e2,e3];
NSLog(@"Events = %@", events);
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"eventDate.cbvTimeIntervalSinceStartOfDay" ascending:YES];
NSArray *sortedEvents = [events sortedArrayUsingDescriptors:@[sortDescriptor]];
NSLog(@"Sorted Events = %@", sortedEvents);

执行此代码会显示以下输出:

2013-01-15 15:50:54.221 DateSortingFun[67319:c07] Events = (
    "<Event: 0x717b050>, name = e1, eventDate = Tuesday, January 15, 2013, 3:50:54 PM Mountain Standard Time",
    "<Event: 0x717b620>, name = e2, eventDate = Monday, January 14, 2013, 5:50:54 PM Mountain Standard Time",
    "<Event: 0x717b650>, name = e3, eventDate = Tuesday, January 15, 2013, 4:50:54 PM Mountain Standard Time" )


2013-01-15 15:50:54.222 DateSortingFun[67319:c07] Sorted Events = (
    "<Event: 0x717b050>, name = e1, eventDate = Tuesday, January 15, 2013, 3:50:54 PM Mountain Standard Time",
    "<Event: 0x717b650>, name = e3, eventDate = Tuesday, January 15, 2013, 4:50:54 PM Mountain Standard Time",
    "<Event: 0x717b620>, name = e2, eventDate = Monday, January 14, 2013, 5:50:54 PM Mountain Standard Time" )

关于ios - 仅使用时间按日期对数组进行排序？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14347532/