获得第一个月,最后一个月？

Question

我想获得第一个月,最后一个月,我试试

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

我怎么能得到最后一个月？

请给我一些建议,谢谢!

Answer 1

NSDate我写的一些类别方法将帮助您:

这是一个简单的方法来查找一个月的开头:

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

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

    return startOfMonth;
}

它所做的只是从当天获取年份和月份组件,然后再次转换回日期.

在本月底,我使用了几种方法:

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

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

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

和

- (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;
}

这是一个3个步骤 - 在当前日期添加一个月,找到下个月的开始,然后减去1秒以查找本月末.

斯威夫特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

    }
}

斯威夫特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

尝试这个技巧.

Day Param:1是获得本月的第一个日期

Day Param:0是通过获取下个月之前的月份的最后日期来获取本月的最后一个日期(表示本月))

- (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

}

下一个

- (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];
}

不要忘记正确的日期形式

针对IOS 8.0进行了更新

- (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

}

下一个

- (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];
}

现在你正在与:

• NSCalendarUnitYear
• NSCalendarUnitWeekOfMonth
• NSCalendarIdentifierGregorian

Answer 3

您可以使用以下命令获取该月的最后一个日期：-

NSDate currDate=[NSDate date];

-(NSString *)getLastDateMonth:(NSDate *)currDate{

  NSCalendar *gregCalendar=[[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];

  NSDateComponents *components=[gregCalendar components:NSMonthCalendarUnit|NSYearCalendarUnit fromDate:currDate];
  NSInteger month=[components month];
  NSInteger year=[components year];

  if (month==12) {
    [components setYear:year+1];
    [components setMonth:1];
  } else {
    [components setMonth:month+1];
  }
  [components setDay:1];

  NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateStyle:NSDateFormatterShortStyle];
  NSString *lastDateOfMonth = [dateFormat stringFromDate:(NSDate *)[[gregCalendar dateFromComponents:components] dateByAddingTimeInterval:-86400]];
  dateFormat=nil;
  return lastDateOfMonth;
}