How to add one month to an NSDate?

How To Add Month To NSDate Object?

NSDate *someDate = [NSDate Date] + 30Days.....;
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最佳答案

You need to use NSDateComponents:

NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
[dateComponents setMonth:1];
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *newDate = [calendar dateByAddingComponents:dateComponents toDate:originalDate options:0];
[dateComponents release]; // If ARC is not used, release the date components
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Do you want to add a "month" or exactly 30 days? If it's 30 days, you do it like this:

// get a date
NSDate *date = [NSDate dateWithNaturalLanguageString:@"2011-01-02"];


// add 30 days to it (in seconds)
date = [date dateByAddingTimeInterval:(30 * 24 * 60 * 60)];


NSLog(@"%@", date); // 2011-02-01

Note: this will not take daylight savings time transitions or leap seconds into account. Use @TheEye's answer if you need that

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With iOS 8 and OS X 10.9 you can add NSCalendarUnits using NSCalendar:

Objective-C

NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *someDate = [cal dateByAddingUnit:NSCalendarUnitMonth value:1 toDate:[NSDate date] options:0];

Swift 3

let date = Calendar.current.date(byAdding: .month, value: 1, to: Date())

Swift 2

let cal = NSCalendar.currentCalendar()
let date = cal.dateByAddingUnit(.Month, value: 1, toDate: NSDate(), options: [])
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For example, to add 3 months to the current date in Swift:

let date = NSCalendar.currentCalendar().dateByAddingUnit(.MonthCalendarUnit, value: 3, toDate: NSDate(), options: nil)!

In Swift 2.0:

let date = NSCalendar.currentCalendar().dateByAddingUnit(.Month, value: 3, toDate: NSDate(), options: [])
  • The new OptionSetType structure of NSCalendarUnit lets you more simply specify .Month
  • Parameters that take OptionSetType (like the options: parameter, which takes NSCalendarOptions) can't be nil, so pass in an empty set ([]) to represent "no options".
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In Swift 2.0

    let startDate = NSDate()
let dateComponent = NSDateComponents()
dateComponent.month = 1
let cal = NSCalendar.currentCalendar()
let endDate = cal.dateByAddingComponents(dateComponent, toDate: startDate, options: NSCalendarOptions(rawValue: 0))
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FOR SWIFT 3.0

here is function , you can reduce days , month ,day by any count like for example here , i have reduced the current system date's year by 100 year , you can do it for day , month also just set the counter and then store the values in array , and do whatever you want to do with that array 

func currentTime(){


let date = Date()
let calendar = Calendar.current
var year = calendar.component(.year, from: date)
let month = calendar.component(.month, from: date)
let  day = calendar.component(.day, from: date)
let pastyear = year - 100
var someInts = [Int]()
printLog(msg: "\(day):\(month):\(year)" )


for _ in pastyear...year        {
year -= 1
print("\(year) ")
someInts.append(year)
}


print(someInts)
}
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Other answers work fine if your desired behaviour is adding a month and allowing for daylight savings time. This produces results such that:

01/03/2017 00:00 + 1 month -> 31/03/2017 23:00
01/10/2017 00:00 + 1 month -> 01/11/2017 01:00

However I wanted to ignore the hour lost or gained by DST, such that:

01/03/2017 00:00 + 1 month -> 01/04/2017 00:00
01/10/2017 00:00 + 1 month -> 01/11/2017 00:00

So I check if a DST boundary is passed, and if so either add or subtract an hour accordingly:

func offsetDaylightSavingsTime() -> Date {
// daylightSavingTimeOffset is either + 1hr or + 0hr. To offset DST for a given date, we need to add an hour or subtract an hour
// +1hr -> +1hr
// +0hr -> -1hr
// offset = (daylightSavingTimeOffset * 2) - 1 hour


let daylightSavingsTimeOffset = TimeZone.current.daylightSavingTimeOffset(for: self)
let oneHour = TimeInterval(3600)
let offset = (daylightSavingsTimeOffset * 2) - oneHour
return self.addingTimeInterval(offset)
}


func isBetweeen(date date1: Date, andDate date2: Date) -> Bool {
return date1.compare(self).rawValue * self.compare(date2).rawValue >= 0
}


func offsetDaylightSavingsTimeIfNecessary(nextDate: Date) -> Date {
if let nextDST = TimeZone.current.nextDaylightSavingTimeTransition(after: self) {
if nextDST.isBetweeen(date: self, andDate: nextDate){
let offsetDate = nextDate.offsetDaylightSavingsTime()
let difference = offsetDate.timeIntervalSince(nextDate)
return nextDate.addingTimeInterval(difference)
}
}


return nextDate
}


func dateByAddingMonths(_ months: Int) -> Date? {
if let dateWithMonthsAdded = Calendar.current.date(byAdding: .month, value: months, to: self) {
return self.offsetDaylightSavingsTimeIfNecessary(nextDate: dateWithMonthsAdded)
}


return self
}

Test:

func testDateByAddingMonths() {


let date1 = "2017-01-01T00:00:00Z".asDate()
let date2 = "2017-02-01T00:00:00Z".asDate()
let date3 = "2017-03-01T00:00:00Z".asDate()
let date4 = "2017-04-01T00:00:00Z".asDate()
let date5 = "2017-05-01T00:00:00Z".asDate()
let date6 = "2017-06-01T00:00:00Z".asDate()
let date7 = "2017-07-01T00:00:00Z".asDate()
let date8 = "2017-08-01T00:00:00Z".asDate()
let date9 = "2017-09-01T00:00:00Z".asDate()
let date10 = "2017-10-01T00:00:00Z".asDate()
let date11 = "2017-11-01T00:00:00Z".asDate()
let date12 = "2017-12-01T00:00:00Z".asDate()
let date13 = "2018-01-01T00:00:00Z".asDate()
let date14 = "2018-02-01T00:00:00Z".asDate()


var testDate = "2017-01-01T00:00:00Z".asDate()
XCTAssertEqual(testDate, date1)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date2)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date3)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date4)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date5)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date6)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date7)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date8)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date9)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date10)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date11)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date12)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date13)


testDate = testDate.dateByAddingMonths(1)!
XCTAssertEqual(testDate, date14)
}

For completeness, the .asDate() method I'm using

extension String {


static let dateFormatter = DateFormatter()
func checkIsValidDate() -> Bool {
return self.tryParseToDate() != nil
}


func tryParseToDate() -> Date? {
String.dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
return String.dateFormatter.date(from: self)
}


func asDate() -> Date {
return tryParseToDate()!
}
}
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For swift 3.0

extension Date {
func addMonth(n: Int) -> Date {
let cal = NSCalendar.current
return cal.date(byAdding: .month, value: n, to: self)!
}
func addDay(n: Int) -> Date {
let cal = NSCalendar.current
return cal.date(byAdding: .day, value: n, to: self)!
}
func addSec(n: Int) -> Date {
let cal = NSCalendar.current
return cal.date(byAdding: .second, value: n, to: self)!
}
}
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Do you want to add a "month" or exactly 30 days or one day or one year based on user selecting automatically calculation to date.

  NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]
init];
[dateFormatter setDateFormat:@"YYYY-MM-dd HH:mm:ss"];
NSDateComponents *components = [calendar components:(NSCalendarUnitHour | NSCalendarUnitMinute) fromDate:[NSDate date]];


NSDateComponents *dayComponent = [[NSDateComponents alloc]
init];
int changeid = [here number of days intValue];


dayComponent.hour = changeid;


NSCalendar *theCalendar = [NSCalendar currentCalendar];
NSDate *nextDate = [theCalendar
dateByAddingComponents:dayComponent toDate:[dateFormatter
dateFromString:self.fromDateTF.text] options:0];


NSLog(@"nextDate: %@ ...", nextDate);
[self.toDateTF setText:[dateFormatter
stringFromDate:nextDate]];

////month


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