NSDateComponents *dayComponent = [[[NSDateComponents alloc] init] autorelease];
dayComponent.day = 1;

NSCalendar *theCalendar = [NSCalendar currentCalendar];
dateToBeIncremented = [theCalendar dateByAddingComponents:dayComponent toDate:dateToBeIncremented options:0];

好吧，我以为这对我有用。但是，如果您使用它在2013年3月31日之后添加一天，它将返回一个只添加了23小时的日期。它实际上可能有24小时，但在计算中只添加了23:00小时。

类似地，如果您向前扩展到2013年10月28日，代码将增加25小时，从而导致日期时间为2013-10-28 01:00:00。

为了添加一天，我正在做的事情在顶部，添加:

NSDate *newDate1 = [now dateByAddingTimeInterval:60*60*24*daysToAdd];

复杂，主要是由于夏令时。

它的工作原理!

NSCalendar *calendar = [NSCalendar currentCalendar];
NSCalendarUnit unit = NSCalendarUnitDay;
NSInteger value = 1;
NSDate *today = [NSDate date];
NSDate *tomorrow = [calendar dateByAddingUnit:unit value:value toDate:today options:NSCalendarMatchStrictly];

NSDate *today=[NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier: NSGregorianCalendar];
NSDateComponents *components=[[NSDateComponents alloc] init];
components.day=1;
NSDate *targetDate =[calendar dateByAddingComponents:components toDate:today 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)

Swift 5.0:

var dayComponent    = DateComponents()
dayComponent.day    = 1 // For removing one day (yesterday): -1
let theCalendar     = Calendar.current
let nextDate        = theCalendar.date(byAdding: dayComponent, to: Date())
print("nextDate : \(nextDate)")

目标C:

NSDateComponents *dayComponent = [[NSDateComponents alloc] init];
dayComponent.day = 1;

NSCalendar *theCalendar = [NSCalendar currentCalendar];
NSDate *nextDate = [theCalendar dateByAddingComponents:dayComponent toDate:[NSDate date] options:0];

NSLog(@"nextDate: %@ ...", nextDate);

这应该是不言而喻的。

swift 5更新

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