objective-c - 计算下一个生日日期

Question

从 @"02/29/1980" 这样的字符串计算(和创建)下一个生日 NSDate 的最简单方法是什么？ (日/月/年)

Answer 1

这是我的做法。

请注意，在本例中，您选择的日期是闰日，因此结果将显示非闰年年份中的第二天。 “正常”日期将显示新年的同一天。

NSString *birthdayString        = @"02/29/1980";

// Convert the string to a NSDate
NSDateFormatter *formatter      = [NSDateFormatter new];
formatter.timeZone              = [NSTimeZone timeZoneWithName:@"UTC"];
formatter.dateFormat            = @"MM/dd/yyyy";
NSDate *birthday                = [formatter dateFromString:birthdayString];

// Break the date apart into its components and change the year to the current year
NSCalendar *cal                 = [NSCalendar currentCalendar];
cal.timeZone                    = [NSTimeZone timeZoneWithName:@"UTC"];
NSDate *now                     = [NSDate date];
NSDateComponents *currentComps  = [cal components:NSYearCalendarUnit fromDate:now];
NSDateComponents *birthdayComps = [cal components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit
                                         fromDate:birthday];
birthdayComps.year              = currentComps.year;

// Create the date from the modified components
NSDate *birthdayDate            = [cal dateFromComponents:birthdayComps];

// Check to see if the birthday has passed yet this year, and if not add one year
if ([now compare:birthdayDate] == NSOrderedDescending)
{
    NSDateComponents *oneYear = [NSDateComponents new];
    oneYear.year = 1;
    birthdayDate = [cal dateByAddingComponents:oneYear toDate:birthdayDate options:0];
}

NSLog(@"Next Birthday: %@", birthdayDate);
// Results: Next Birthday: 2013-03-01