swift 5更新

let nextDate = fromDate.addingTimeInterval(60*60*24)

斯威夫特2.0

let today = NSDate()    
let calendar = NSCalendar.currentCalendar()
let tomorrow = calendar.dateByAddingUnit(.Day, value: 1, toDate: today, options: NSCalendarOptions.MatchFirst)

斯威夫特5

let today = Date()
let nextDate = Calendar.current.date(byAdding: .day, value: 1, to: today)

objective - c

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
// now build a NSDate object for the next day
NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];
[offsetComponents setDay:1];
NSDate *nextDate = [gregorian dateByAddingComponents:offsetComponents toDate: [NSDate date] options:0];

Swift 4.0(在这个精彩的答案中与Swift 3.0相同，只是为了让像我这样的新手清楚)

let today = Date()
let yesterday = Calendar.current.date(byAdding: .day, value: -1, to: today)

我也有同样的问题;使用NSDate扩展:

- (id)dateByAddingYears:(NSUInteger)years
                 months:(NSUInteger)months
                   days:(NSUInteger)days
                  hours:(NSUInteger)hours
                minutes:(NSUInteger)minutes
                seconds:(NSUInteger)seconds
{
    NSDateComponents * delta = [[[NSDateComponents alloc] init] autorelease];
    NSCalendar * gregorian = [[[NSCalendar alloc]
                               initWithCalendarIdentifier:NSCalendarIdentifierGregorian] autorelease];

    [delta setYear:years];
    [delta setMonth:months];
    [delta setDay:days];
    [delta setHour:hours];
    [delta setMinute:minutes];
    [delta setSecond:seconds];

    return [gregorian dateByAddingComponents:delta toDate:self options:0];
}

你可以使用NSDate的方法- (id)dateByAddingTimeInterval:(NSTimeInterval)秒，其中秒为60 * 60 * 24 = 86400