Question

I have created a custom class for my dates and need move dates forward and backward via button . Here is my code which shows Today date :

- (NSString *) showToday {

    NSCalendar *myCal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];    
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

    [dateFormatter setCalendar:myCal];

    offsetComponents = [[NSDateComponents alloc] init];
//shows today 
    [offsetComponents setDay:0];

    NSDate *nextDate = [myCal dateByAddingComponents:offsetComponents toDate:[NSDate date] options:0];

    [dateFormatter setDateFormat:@"d"];
    NSString *currDay = [dateFormatter stringFromDate:nextDate];

    [NSString stringWithFormat:@"%@",currDay];

    [myCal release];
    [dateFormatter release];
    return currDay;
}

on my viewController :

customClass = [[customClass alloc]init];

    day.text = [cal showToday];

so if I need to move forward a date I just change this line code to :

//show tomorrow 
[offsetComponents setDay:1];

so How can I dynamically change this line and change dates via button ?

Answer 1

You can declare an int for your offsetComponents variable. then :

- (IBAction)moveDatesForward:(id)sender {

    NSCalendar *persCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSPersianCalendar];    
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    NSLocale *IRLocal = [[NSLocale alloc] initWithLocaleIdentifier:@"fa_IR"];
    [dateFormatter setLocale:IRLocal];
    [dateFormatter setCalendar:persCalendar];

    offsetComponents = [[NSDateComponents alloc] init];

    offsetComponents.day = _dayNumber;

    NSDate *nextDate = [persCalendar dateByAddingComponents:offsetComponents toDate:[NSDate date] options:0];

    [dateFormatter setDateFormat:@"d"];
    dayLabel.text = [dateFormatter stringFromDate:nextDate];

    [NSString stringWithFormat:@"%@",dayLabel];

    [persCalendar release];
    [dateFormatter release];

      _dayNumber ++;

}