Get firstdate, lastdate of month?

Question

I want to get firstdate、lastdate of month，I try

NSDateComponents *components = [calendar components:units fromDate:[NSDate date]];
[components setDay:1];
self.currentDate = [calendar dateFromComponents:components];
int m = components.month;
int y = components.year;
int d = components.day;

log: 2012,5,1

How can i get lastdate od month?

please give me some advice，thank you!!

Answer 1

Some NSDate category methods I wrote will help you:

Here's an easy way to find the start of a month:

 (NSDate *) startOfMonth
{
    NSCalendar * calendar = [NSCalendar currentCalendar];

    NSDateComponents * currentDateComponents = [calendar components: NSYearCalendarUnit | NSMonthCalendarUnit fromDate: self];
    NSDate * startOfMonth = [calendar dateFromComponents: currentDateComponents];

    return startOfMonth;
}

All it does is take the year and month components from the current day, then convert back to a date again.

For the end of the month, I use a couple of methods:

- (NSDate *) dateByAddingMonths: (NSInteger) monthsToAdd
{
    NSCalendar * calendar = [NSCalendar currentCalendar];

    NSDateComponents * months = [[NSDateComponents alloc] init];
    [months setMonth: monthsToAdd];

    return [calendar dateByAddingComponents: months toDate: self options: 0];
}

and

- (NSDate *) endOfMonth
{
    NSCalendar * calendar = [NSCalendar currentCalendar];

    NSDate * plusOneMonthDate = [self dateByAddingMonths: 1];
    NSDateComponents * plusOneMonthDateComponents = [calendar components: NSYearCalendarUnit | NSMonthCalendarUnit fromDate: plusOneMonthDate];
    NSDate * endOfMonth = [[calendar dateFromComponents: plusOneMonthDateComponents] dateByAddingTimeInterval: -1]; // One second before the start of next month

    return endOfMonth;
}

This is a 3 step process - add one month to the current date, find the start of the next month, then subtract 1 second to find the end of this month.

---

Swift 3

extension Date {

    func startOfMonth() -> Date? {

        let calendar = Calendar.current
        let currentDateComponents = calendar.dateComponents([.year, .month], from: self)
        let startOfMonth = calendar.date(from: currentDateComponents)

        return startOfMonth
    }

    func dateByAddingMonths(_ monthsToAdd: Int) -> Date? {

        let calendar = Calendar.current
        var months = DateComponents()
        months.month = monthsToAdd

        return calendar.date(byAdding: months, to: self)
    }

    func endOfMonth() -> Date? {

        guard let plusOneMonthDate = dateByAddingMonths(1) else { return nil }

        let calendar = Calendar.current
        let plusOneMonthDateComponents = calendar.dateComponents([.year, .month], from: plusOneMonthDate)
        let endOfMonth = calendar.date(from: plusOneMonthDateComponents)?.addingTimeInterval(-1)

        return endOfMonth

    }
}

---

Swift 2

extension NSDate {

    func startOfMonth() -> NSDate? {

        let calendar = NSCalendar.currentCalendar()
        let currentDateComponents = calendar.components(.CalendarUnitYear | .CalendarUnitMonth, fromDate: self)
        let startOfMonth = calendar.dateFromComponents(currentDateComponents)

        return startOfMonth
    }

    func dateByAddingMonths(monthsToAdd: Int) -> NSDate? {

        let calendar = NSCalendar.currentCalendar()
        let months = NSDateComponents()
        months.month = monthsToAdd

        return calendar.dateByAddingComponents(months, toDate: self, options: nil)
    }

    func endOfMonth() -> NSDate? {

        let calendar = NSCalendar.currentCalendar()
        if let plusOneMonthDate = dateByAddingMonths(1) {
            let plusOneMonthDateComponents = calendar.components(.CalendarUnitYear | .CalendarUnitMonth, fromDate: plusOneMonthDate)

            let endOfMonth = calendar.dateFromComponents(plusOneMonthDateComponents)?.dateByAddingTimeInterval(-1)

            return endOfMonth
        }

        return nil
    }
}

Answer 2

Try this trick.

Day Param: 1 is to Get first date of this month

Day Param: 0 is to Get last date of this month by getting last date of month previous to next month (means this month))

- (void)returnDate:(NSDate *)date {

    NSCalendar * calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit;
    NSDateComponents *comps = [calendar components:unitFlags fromDate:date];

    NSDate * firstDateOfMonth = [self returnDateForMonth:comps.month year:comps.year day:1];
    NSDate * lastDateOfMonth = [self returnDateForMonth:comps.month+1 year:comps.year day:0];

    NSLog(@"date %@", date);              // date 2013-06-20
    NSLog(@"First %@", firstDateOfMonth); // firstDateOfMonth 2013-06-01
    NSLog(@"Last %@", lastDateOfMonth);   // lastDateOfMonth  2013-06-30

}

Next

- (NSDate *)returnDateForMonth:(NSInteger)month year:(NSInteger)year day:(NSInteger)day {

    NSDateComponents *components = [[NSDateComponents alloc] init];

    [components setDay:day];
    [components setMonth:month];
    [components setYear:year];

    NSCalendar *gregorian = [[NSCalendar alloc]
                             initWithCalendarIdentifier:NSGregorianCalendar];
    return [gregorian dateFromComponents:components];
}

Don't forget for right Date Formater

Updated for IOS 8.0

- (void)returnDate:(NSDate *)date { 
    NSCalendar * calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
    unsigned unitFlags = NSCalendarUnitYear | NSCalendarUnitMonth;
    NSDateComponents *comps = [calendar components:unitFlags fromDate:date];

    NSDate * firstDateOfMonth = [self returnDateForMonth:comps.month year:comps.year day:1];
    NSDate * lastDateOfMonth = [self returnDateForMonth:comps.month+1 year:comps.year day:0];

    NSLog(@"date %@", date);              // date 2013-06-20
    NSLog(@"First %@", firstDateOfMonth); // firstDateOfMonth 2013-06-01
    NSLog(@"Last %@", lastDateOfMonth);   // lastDateOfMonth  2013-06-30

}

Next

- (NSDate *)returnDateForMonth:(NSInteger)month year:(NSInteger)year day:(NSInteger)day {

    NSDateComponents *components = [[NSDateComponents alloc] init];

    [components setDay:day];
    [components setMonth:month];
    [components setYear:year];

    NSCalendar *gregorian = [[NSCalendar alloc]
                         initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
    return [gregorian dateFromComponents:components];
}

Now your are working with:

• NSCalendarUnitYear
• NSCalendarUnitWeekOfMonth
• NSCalendarIdentifierGregorian