How can we get Next Date From Entered Date based on given repeate period ?

I am new to iPhone.

I want to find out the next date from given date based on repeat period.

For example :

I want function as follows ...

• given date : 31'May 2011 and Repeat : Monthly given as argument then the next date should be returned 31'July 2011 (as June don't have 31st day)

• And function should be smart enough to to calculate next leap year day also, if given date : 29'Feb 2008 and Repeat : Yearly given as argument then the next date should be returned 29'Feb 20开发者_JAVA技巧12 (The next leap year day)

• And so on repeat option can be one of these : Daily, Weekly(On selected day of week), Monthly, Yearly, None(No repeat at all)

// start by retrieving day, weekday, month and year components for yourDate
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *todayComponents = [gregorian components:(NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) yourDate];
NSInteger theDay = [todayComponents day];
NSInteger theMonth = [todayComponents month];
NSInteger theYear = [todayComponents year];

// now build a NSDate object for yourDate using these components
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setDay:theDay]; 
[components setMonth:theMonth]; 
[components setYear:theYear];
NSDate *thisDate = [gregorian dateFromComponents:components];
[components release];

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

This is copied from How can i get next date using NSDate? and the credit goes to @Massimo Cafaro for this answer.

To get tomorrow's date use the dateByAddingTimeInterval method.

// Start with today
NSDate *today = [NSDate date];

// Add on the number of seconds in a day
NSTimeInterval oneDay = 60 * 60 * 24;
NSDate *tomorrow = [today dateByAddingTimeInterval:oneDay];

It's pretty simple to extend that to a week etc

NSTimeInterval oneWeek = oneDay * 7;
NSDate *nextWeek = [today dateByAddingTimeInterval:oneWeek];

try this :-

- (NSDate *)dateFromDaysOffset:(NSInteger)daysOffset
{
    // start by retrieving day, weekday, month and year components for yourDate
    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];
    [offsetComponents setDay:daysOffset];
    NSDate *offsetDate = [gregorian dateByAddingComponents:offsetComponents toDate:self options:0];
    [offsetComponents release];
    [gregorian release];    

    return offsetDate;
}