NSDate beginning of day and end of day

问题:

    -(NSDate *)beginningOfDay:(NSDate *)date
{
    NSCalendar *cal = [NSCalendar currentCalendar];
    NSDateComponents *components = [cal components:( NSMonthCalendarUnit | NSYearCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) fromDate:date];

    [components setHour:0];
    [components setMinute:0];
    [components setSecond:0];

    return [cal dateFromComponents:components];

}

-(NSDate *)endOfDay:(NSDate *)date
{
    NSCalendar *cal = [NSCalendar currentCalendar];
    NSDateComponents *components = [cal components:(  NSMonthCalendarUnit | NSYearCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) fromDate:date];

    [components setHour:23];
    [components setMinute:59];
    [components setSecond:59];

    return [cal dateFromComponents:components];

}

When I call : [self endOfDay:[NSDate date]]; I get the first of the month ... Why is that? I use this two methods because I need an interval that is from the first second of the first date (beginningOfDay:date1) to the last second of the second date (endOfDay:Date2) ...

回答1:

You are missing NSDayCalendarUnit in

NSDateComponents *components = [cal components:( NSMonthCalendarUnit | NSYearCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) fromDate:date];

回答2:

Start Of Day / End Of Day — Swift 4

  // Extension

extension Date {
    var startOfDay: Date {
        return Calendar.current.startOfDay(for: self)
    }

    var endOfDay: Date {
        var components = DateComponents()
        components.day = 1
        components.second = -1
        return Calendar.current.date(byAdding: components, to: startOfDay)!
    }

    var startOfMonth: Date {
        let components = Calendar.current.dateComponents([.year, .month], from: startOfDay)
        return Calendar.current.date(from: components)!
    }

    var endOfMonth: Date {
        var components = DateComponents()
        components.month = 1
        components.second = -1
        return Calendar.current.date(byAdding: components, to: startOfMonth)!
    }
}

// End of day = Start of tomorrow minus 1 second
// End of month = Start of next month minus 1 second

回答3:

In iOS 8+ this is really convenient; you can do:

let startOfDay = NSCalendar.currentCalendar().startOfDayForDate(date)

To get the end of day then just use the NSCalendar methods for 23 hours, 59 mins, 59 seconds, depending on how you define end of day.

// Swift 2.0
let components = NSDateComponents()
components.hour = 23
components.minute = 59
components.second = 59
let endOfDay = NSCalendar.currentCalendar().dateByAddingComponents(components, toDate: startOfDay, options: NSCalendarOptions(rawValue: 0))

Date Math

Apple iOS NSCalendar Documentation. (See Section: Calendrical Calculations)

NSCalendar methods discussed by NSHipster.

回答4:

My Swift extensions for NSDate:

Swift 1.2

extension NSDate {

    func beginningOfDay() -> NSDate {
        var calendar = NSCalendar.currentCalendar()
        var components = calendar.components(.CalendarUnitYear | .CalendarUnitMonth | .CalendarUnitDay, fromDate: self)
        return calendar.dateFromComponents(components)!
    }

    func endOfDay() -> NSDate {
        var components = NSDateComponents()
        components.day = 1
        var date = NSCalendar.currentCalendar().dateByAddingComponents(components, toDate: self.beginningOfDay(), options: .allZeros)!
        date = date.dateByAddingTimeInterval(-1)!
        return date
    }
}

Swift 2.0

extension NSDate {

    func beginningOfDay() -> NSDate {
        let calendar = NSCalendar.currentCalendar()
        let components = calendar.components([.Year, .Month, .Day], fromDate: self)
        return calendar.dateFromComponents(components)!
    }

    func endOfDay() -> NSDate {
        let components = NSDateComponents()
        components.day = 1
        var date = NSCalendar.currentCalendar().dateByAddingComponents(components, toDate: self.beginningOfDay(), options: [])!
        date = date.dateByAddingTimeInterval(-1)
        return date
    }
}

回答5:

Swift 4 Simple and more precise answer.

Start time: 00:00:00

End time: 23:59:59.5

var date = Date() // current date or replace with a specific date
var calendar = Calendar.current
let startTime = calendar.startOfDay(for: date)
let endTime = calendar.date(bySettingHour: 23, minute: 59, second: 59, of: date)

回答6:

Swift 4.2 - XCode 10 with Date class instead of NSDate and Calender instead of NSCalender

extension Date {

    var startOfDay : Date {
        let calendar = Calendar.current
        let unitFlags = Set<Calendar.Component>([.year, .month, .day])
        let components = calendar.dateComponents(unitFlags, from: self)
        return calendar.date(from: components)!
   }

    var endOfDay : Date {
        var components = DateComponents()
        components.day = 1
        let date = Calendar.current.date(byAdding: components, to: self.startOfDay)
        return (date?.addingTimeInterval(-1))!
    }
}

Usage:

    let myDate = Date()
    let startOfDate = myDate.startOfDay
    let endOfDate = myDate.endOfDay

回答7:

You don't have to set up the components to zero, just ignore them:

-(NSDate *)beginningOfDay:(NSDate *)date
{
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:date];
    return [calendar dateFromComponents:components];
}

回答8:

Swift 3

  class func today() -> NSDate {
        return NSDate()
    }

    class func dayStart() -> NSDate {
          return NSCalendar.current.startOfDay(for: NSDate() as Date) as NSDate
    }

    class func dayEnd() -> NSDate {
        let components = NSDateComponents()
        components.day = 1
        components.second = -1
        return NSCalendar.current.date(byAdding: components as DateComponents, to: self.dayStart() as Date)
    }

回答9:

For me none of the answers here and else where on stackoverflow worked. To get start of today i did this.

NSCalendar * gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian]; 
[gregorian setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];    
NSDateComponents *components = [gregorian components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:[NSDate date]]; 
[components setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]]; 
NSDate *beginningOfToday = [gregorian dateFromComponents:components];

Note this [gregorian setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]]; and [components setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];.

When a calendar is created it gets initialised with current timezone and when date is extracted from its components, since NSDate has no timezone, the date from current timezone is considered as UTC timezone. So we need to set the timezone before extracting components and later when extracting date from these components.

回答10:

Swift3 Using *XCode8
Apple is removing the NS from the class name so that NSDate can be swapped out to Date. You may get a compiler warning if you try to cast them saying they will always fail, but they work fine when you run them in the playground.

I replaced my generated NSDate in core data model with Date and they still work.

extension Date {
  func startTime() -> Date {
    return Calendar.current.startOfDay(for: self)
  }

  func endTime() -> Date {
    var components = DateComponents()
    components.day = 1
    components.second = -1
    return Calendar.current.date(byAdding: components, to: startTime())!
  }
}

回答11:

One more way to get result:

NSDate *date = [NSDate date];

NSDateComponents *components = [[NSDateComponents alloc] init];
components.day = [[NSCalendar currentCalendar] ordinalityOfUnit:(NSCalendarUnitDay) inUnit:(NSCalendarUnitEra) forDate:date];
NSDate *dayBegin = [[NSCalendar currentCalendar] dateFromComponents:components];

components.day += 1;
NSDate *dayEnd = [[NSCalendar currentCalendar] dateFromComponents:components];

回答12:

You are missing NSDayCalendarUnit in the components.

回答13:

Since iOS 8.0+ / macOS 10.12+ / tvOS 10.0+ / watchOS 3.0+ there is a built in function in the Foundation, which you can use out of the box. No need to implement own functions.

public func startOfDay(for date: Date) -> Date

So you can use it this way:

let midnightDate = Calendar(identifier: .gregorian).startOfDay(for: Date())

It's worth to remember, that this takes upon consideration the device time zone. You can set .timeZone on calendar if you want to have eg UTC zone.

Link to the Apple reference pages: https://developer.apple.com/reference/foundation/nscalendar/1417161-startofday.

回答14:

Just another way using dateInterval(of:start:interval:for:) of Calendar

On return startDate contains the start of the day and interval the number of seconds in the day.

func startAndEnd(of date : Date) -> (start : Date, end : Date) {
    var startDate = Date()
    var interval : TimeInterval = 0.0
    Calendar.current.dateInterval(of: .day, start: &startDate, interval: &interval, for: date)
    var endDate = startDate.addingTimeInterval(interval-1)
    return (start : startDate, end : endDate)
}

let (start, end) = startAndEnd(of: Date())
print(start, end)

回答15:

For swift 4

    var calendar = Calendar.current
    calendar.timeZone = NSTimeZone(abbreviation: "UTC")! as TimeZone
    let dateAtMidnight = calendar.startOfDay(for: Date())

    //For End Date
    var components = DateComponents()
    components.day = 1
    components.second = -1

    let dateAtEnd = calendar.date(byAdding: components, to: dateAtMidnight)

    print("dateAtMidnight :: \(dateAtMidnight)")
    print("dateAtEnd :: \(dateAtEnd!)")

回答16:

extension Date {
    func stringFrom(dateFormat: String) -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = dateFormat
        return formatter.string(from: self)
    }

    func firstSecondInDay() -> Date {
        let dayStr = self.stringFrom(dateFormat: "yyyy-MM-dd")
        let firstSecondStr = "\(dayStr) 00:00:00"
        let format = DateFormatter()
        format.dateFormat = "yyyy-MM-dd HH:mm:ss"
        return format.date(from: firstSecondStr)!
    }

    func lastSecondInDay() -> Date {
        let dayStr = self.stringFrom(dateFormat: "yyyy-MM-dd")
        let laseSecondStr = "\(dayStr) 23:59:59"
        let format = DateFormatter()
        format.dateFormat = "yyyy-MM-dd HH:mm:ss"
        return format.date(from: laseSecondStr)!
    }
}

回答17:

Objective-C

NSCalendar * calendar = [NSCalendar currentCalendar];
NSDate * startDate = [calendar startOfDayForDate:[NSDate date]];
NSLog(@"start date is %@", startDate);

回答18:

Just for reference, simple way to set Start and End of the day in Swift 4,

var comp: DateComponents = Calendar.current.dateComponents([.year, .month, .day, .hour, .minute, .second], from: Date())
comp.hour = 0
comp.minute = 0
comp.second = 0
comp.timeZone = TimeZone(abbreviation: "UTC")!


//Set Start of Day
let startDate : Date = Calendar.current.date(from: comp)!
print(“Day of Start : \(startDate)")


//Set End of Day
comp.hour = 23
comp.minute = 59
comp.second = 59

let endDate : Date = Calendar.current.date(from:comp)!
print("Day of End : \(endDate)")