Comment calculer le temps en heures entre deux dates dans iOS

Comment puis-je calculer le temps écoulé en heures entre deux heures (éventuellement survenant à des jours différents) dans iOS?

La NSDate fonction timeIntervalSinceDate: vous donnera la différence entre deux dates en quelques secondes.

 NSDate* date1 = someDate;
 NSDate* date2 = someOtherDate;
 NSTimeInterval distanceBetweenDates = [date1 timeIntervalSinceDate:date2];
 double secondsInAnHour = 3600;
 NSInteger hoursBetweenDates = distanceBetweenDates / secondsInAnHour;

Voir, la bibliothèque de référence Apple http://developer.apple.com/library/mac/navigation/ ou si vous utilisez Xcode, sélectionnez simplement help / documentation dans le menu.

Voir: comment-convertir-un-nstimeinterval-secondes-en-minutes

--edit: Voir la réponse de ÐąrέÐέvil ci-dessous pour gérer correctement l'heure d'été / secondes intercalaires

NSCalendar *c = [NSCalendar currentCalendar];
NSDate *d1 = [NSDate date];
NSDate *d2 = [NSDate dateWithTimeIntervalSince1970:1340323201];//2012-06-22
NSDateComponents *components = [c components:NSHourCalendarUnit fromDate:d2 toDate:d1 options:0];
NSInteger diff = components.minute;

NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit

Changez les composants nécessaires en jour, heure ou minute, quelle différence vous voulez. Si NSDayCalendarUnitest sélectionné, il renverra le nombre de jours entre deux dates de la même manière pour NSHourCalendarUnitetNSMinuteCalendarUnit

Version Swift 4

let cal = Calendar.current
let d1 = Date()
let d2 = Date.init(timeIntervalSince1970: 1524787200) // April 27, 2018 12:00:00 AM
let components = cal.dateComponents([.hour], from: d2, to: d1)
let diff = components.hour!

-(NSMutableString*) timeLeftSinceDate: (NSDate *) dateT {

    NSMutableString *timeLeft = [[NSMutableString alloc]init];

    NSDate *today10am =[NSDate date];

    NSInteger seconds = [today10am timeIntervalSinceDate:dateT];

    NSInteger days = (int) (floor(seconds / (3600 * 24)));
    if(days) seconds -= days * 3600 * 24;

    NSInteger hours = (int) (floor(seconds / 3600));
    if(hours) seconds -= hours * 3600;

    NSInteger minutes = (int) (floor(seconds / 60));
    if(minutes) seconds -= minutes * 60;

    if(days) {
        [timeLeft appendString:[NSString stringWithFormat:@"%ld Days", (long)days*-1]];
    }

    if(hours) {
        [timeLeft appendString:[NSString stringWithFormat: @"%ld H", (long)hours*-1]];
    }

    if(minutes) {
        [timeLeft appendString: [NSString stringWithFormat: @"%ld M",(long)minutes*-1]];
    }

    if(seconds) {
        [timeLeft appendString:[NSString stringWithFormat: @"%lds", (long)seconds*-1]];
    }

    return timeLeft;
}

Caisse: Il prend en charge l'heure d'été, année bissextile, car il utilise le calendrier iOS pour calculer. Vous pouvez modifier la chaîne et les conditions pour inclure des minutes avec des heures et des jours.

+(NSString*)remaningTime:(NSDate*)startDate endDate:(NSDate*)endDate {

    NSDateComponents *components;
    NSInteger days;
    NSInteger hour;
    NSInteger minutes;
    NSString *durationString;

    components = [[NSCalendar currentCalendar] components: NSCalendarUnitDay|NSCalendarUnitHour|NSCalendarUnitMinute
                                                 fromDate: startDate toDate: endDate options: 0];
    days = [components day];
    hour = [components hour];
    minutes = [components minute];

    if (days > 0) {

        if (days > 1) {
            durationString = [NSString stringWithFormat:@"%d days", days];
        }
        else {
            durationString = [NSString stringWithFormat:@"%d day", days];
        }
        return durationString;
    }

    if (hour > 0) {

        if (hour > 1) {
            durationString = [NSString stringWithFormat:@"%d hours", hour];
        }
        else {
            durationString = [NSString stringWithFormat:@"%d hour", hour];
        }
        return durationString;
    }

    if (minutes > 0) {

        if (minutes > 1) {
            durationString = [NSString stringWithFormat:@"%d minutes", minutes];
        }
        else {
            durationString = [NSString stringWithFormat:@"%d minute", minutes];
        }
        return durationString;
    }

    return @"";
}

Pour ceux qui utilisent swift 3 et plus,

    let dateString1 = "2018-03-15T14:20:00.000Z"
    let dateString2 = "2018-03-20T14:20:00.000Z"

    let Dateformatter = DateFormatter()
    Dateformatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"

    let date1 = Dateformatter.date(from: dateString1)
    let date2 = Dateformatter.date(from: dateString2)

    let distanceBetweenDates: TimeInterval? = date2?.timeIntervalSince(date1!)
    let secondsInAnHour: Double = 3600
    let secondsInDays: Double = 86400
    let secondsInWeek: Double = 604800

    let hoursBetweenDates = Int((distanceBetweenDates! / secondsInAnHour))
    let daysBetweenDates = Int((distanceBetweenDates! / secondsInDays))
    let weekBetweenDates = Int((distanceBetweenDates! / secondsInWeek))

    print(weekBetweenDates,"weeks")//0 weeks
    print(daysBetweenDates,"days")//5 days
    print(hoursBetweenDates,"hours")//120 hours