我在Swift 2.3中这样做的方式是：
let currentDate = NSDate()
let currentCalendar = NSCalendar.currentCalendar()
var startDate : NSDate?
var endDate : NSDate?
// The following two lines set the `startDate` and `endDate` to the start of the day
currentCalendar.rangeOfUnit(.Day, startDate: &startDate, interval: nil, forDate: currentDate)
currentCalendar.rangeOfUnit(.Day, startDate: &endDate, interval: nil, forDate: self)
let intervalComps = currentCalendar.components([.Day], fromDate: startDate!, toDate: endDate!, options: [])
print(intervalComps.day)
现在这已经全部改变了Swift 3.我必须使用NSCalendar和NSDate不断地使用as输入，或者找到Swift 3的方法。
在Swift 3中使用它的正确方法是什么？
答案 0 :(得分：73)
在 Swift 4 中，有一个简单的单行程序来获取两个日期之间的天数（或任何其他DateComponent）：
let diffInDays = Calendar.current.dateComponents([.day], from: dateA, to: dateB).day
答案 1 :(得分：39)
事实证明，这在Swift 3中要简单得多：
extension Date {
func interval(ofComponent comp: Calendar.Component, fromDate date: Date) -> Int {
let currentCalendar = Calendar.current
guard let start = currentCalendar.ordinality(of: comp, in: .era, for: date) else { return 0 }
guard let end = currentCalendar.ordinality(of: comp, in: .era, for: self) else { return 0 }
return end - start
}
}
修改
比较两个日期的标准应该在同一个era内，而不是相同的year，因为这两个日期自然会在不同的年份落下。
<强>用法
let yesterday = Date(timeInterval: -86400, since: Date())
let tomorrow = Date(timeInterval: 86400, since: Date())
let diff = tomorrow.interval(ofComponent: .day, fromDate: yesterday)
// return 2
答案 2 :(得分：15)
Swift 4版
let startDate = "2000-11-22"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let formatedStartDate = dateFormatter.date(from: startDate)
let currentDate = Date()
let components = Set<Calendar.Component>([.second, .minute, .hour, .day, .month, .year])
let differenceOfDate = Calendar.current.dateComponents(components, from: formatedStartDate!, to: currentDate)
print (differenceOfDate)
印刷 - 年：16个月：10天：19小时：12分钟：16秒：42是LeapMonth：false
答案 3 :(得分：11)
如果有人想要更具体地遵循以下步骤
1.添加此日期延期
extension Date {
/// Returns the amount of years from another date
func years(from date: Date) -> Int {
return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
}
/// Returns the amount of months from another date
func months(from date: Date) -> Int {
return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
}
/// Returns the amount of weeks from another date
func weeks(from date: Date) -> Int {
return Calendar.current.dateComponents([.weekOfMonth], from: date, to: self).weekOfMonth ?? 0
}
/// Returns the amount of days from another date
func days(from date: Date) -> Int {
return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
}
/// Returns the amount of hours from another date
func hours(from date: Date) -> Int {
return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
}
/// Returns the amount of minutes from another date
func minutes(from date: Date) -> Int {
return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
}
/// Returns the amount of seconds from another date
func seconds(from date: Date) -> Int {
return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
}
/// Returns the amount of nanoseconds from another date
func nanoseconds(from date: Date) -> Int {
return Calendar.current.dateComponents([.nanosecond], from: date, to: self).nanosecond ?? 0
}
/// Returns the a custom time interval description from another date
func offset(from date: Date) -> String {
var result: String = ""
if years(from: date) > 0 { return "\(years(from: date))y" }
if months(from: date) > 0 { return "\(months(from: date))M" }
if weeks(from: date) > 0 { return "\(weeks(from: date))w" }
if seconds(from: date) > 0 { return "\(seconds(from: date))" }
if days(from: date) > 0 { result = result + " " + "\(days(from: date)) D" }
if hours(from: date) > 0 { result = result + " " + "\(hours(from: date)) H" }
if minutes(from: date) > 0 { result = result + " " + "\(minutes(from: date)) M" }
if seconds(from: date) > 0 { return "\(seconds(from: date))" }
return ""
}
}
2.全球定义
fileprivate var timer: Timer?
3.在viewDidLoad或您想要的地方接听此方法
override func viewDidLoad() {
super.viewDidLoad()
self.getRemainingTime()
}
<强> 4.Usage
fileprivate func getRemainingTime() {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
let startDate = "2018-06-02 10:11:12"
let currentDate = dateFormatter.string(from: Date())
if currentDate != startDate {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: (#selector(calculateTime)), userInfo: nil, repeats: true)
RunLoop.current.add(timer!, forMode: RunLoopMode.commonModes)
timer?.fire()
}
else {
self.timer?.invalidate()
self.timer = nil
}
}
func calculateTime() {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
let stdate : String = "2018-06-02 10:11:12"
let startDate = dateFormatter.date(from: stdate)!
let currentDate = Date()
let strTimer : String = startDate.offset(from: currentDate)
if !strTimer.isEmpty {
let stDay: String = "\((Int(strTimer)! % 31536000) / 86400)"
let stHour: String = "\((Int(strTimer)! % 86400) / 3600)"
let stMin: String = "\((Int(strTimer)! % 3600) / 60)"
let stSec: String = "\(Int(strTimer)! % 60)"
yourLabelOutlet.text = "Start In :\(stDay) Days \(stHour) Hours \(stMin) Minutes \(stSec) Seconds"
}
}
像Charm一样工作你可以使用每个单独的字符串到你的UI端， 享受
答案 4 :(得分：7)
在Swift4中，我们可以使用以下代码轻松获得两个不同日历日期之间的天数。
第一个是与当前日期的天数差异。
let previousDate = "2017-03-01"
let currentDate = Date()
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let previousDateFormated : Date? = dateFormatter.date(from: previousDate)
let difference = currentDate.timeIntervalSince(previousDateFormated!)
var differenceInDays = Int(difference/(60 * 60 * 24 ))
print(differenceInDays)
继续上述代码......以下是两个不同日期的天数。上一日期的内容取自上述日期
let futureDate = "2017-12-30"
let futureDateFormatted : Date? = dateFormatter.date(from: futureDate)
differenceInDays = (futureDateFormatted?.timeIntervalSince(previousDateFormated!))! / (60 * 60 * 24)
print(differenceInDays)
答案 5 :(得分：6)
private func calculateDaysBetweenTwoDates(start: Date, end: Date) -> Int {
let currentCalendar = Calendar.current
guard let start = currentCalendar.ordinality(of: .day, in: .era, for: start) else {
return 0
}
guard let end = currentCalendar.ordinality(of: .day, in: .era, for: end) else {
return 0
}
return end - start
}
答案 6 :(得分：2)
在另一个线程上找到了这个，但最终对我来说最简单的解决方案是使用Swift 4：
let previousDate = ENTER DATE HERE
let now = Date()
let formatter = DateComponentsFormatter()
formatter.unitsStyle = .brief // May delete the word brief to let Xcode show you the other options
formatter.allowedUnits = [.month, .day, .hour]
formatter.maximumUnitCount = 1 // Show just one unit (i.e. 1d vs. 1d 6hrs)
let stringDate = formatter.string(from: previousDate, to: now)
答案 7 :(得分：1)
如果某人需要显示所有时间单位，例如“小时，分钟，秒”，而不仅仅是“小时”。假设两个日期之间的时差是1小时59分钟20秒。此功能将显示“ 1h 59m 20s”。
这是我的代码：
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'hh:mm:ss"
let start = dateFormatter.date(from: "2019-01-31T07:45:00")!
let end = dateFormatter.date(from: "2019-03-01T06:30:00")!
print("Date Difference : ", end.offsetFrom(date: start))
功能定义：
extension Date {
func offsetFrom(date : Date) -> String {
let dayHourMinuteSecond: Set = [.day, .hour, .minute, .second]
let difference = NSCalendar.current.dateComponents(dayHourMinuteSecond, from: date, to: self);
let seconds = "\(difference.second ?? 0)s"
let minutes = "\(difference.minute ?? 0)m" + " " + seconds
let hours = "\(difference.hour ?? 0)h" + " " + minutes
let days = "\(difference.day ?? 0)d" + " " + hours
if let day = difference.day, day > 0 { return days }
if let hour = difference.hour, hour > 0 { return hours }
if let minute = difference.minute, minute > 0 { return minutes }
if let second = difference.second, second > 0 { return seconds }
return ""
}
}
答案 8 :(得分：1)
import Foundation
extension DateComponents {
func dateComponentsToTimeString() -> String {
var hour = "\(self.hour!)"
var minute = "\(self.minute!)"
var second = "\(self.second!)"
if self.hour! < 10 { hour = "0" + hour }
if self.minute! < 10 { minute = "0" + minute }
if self.second! < 10 { second = "0" + second }
let str = "\(hour):\(minute):\(second)"
return str
}
}
extension Date {
func offset(from date: Date)-> DateComponents {
let components = Set<Calendar.Component>([.second, .minute, .hour, .day, .month, .year])
let differenceOfDate = Calendar.current.dateComponents(components, from: date, to: self)
return differenceOfDate
}
}
使用：
var durationString: String {
return self.endTime.offset(from: self.startTime).dateComponentsToTimeString()
}
答案 9 :(得分：0)
private func days(actual day1:[Int],expect day2:[Int]) -> Int {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let first = "\(day1[2])-\(day1[1])-\(day1[0])"
let firstDate = dateFormatter.date(from:first)!
let last = "\(day2[2])-\(day2[1])-\(day2[0])"
let lastDate = dateFormatter.date(from:last)!
let currentCalendar = NSCalendar.current
let components = currentCalendar.dateComponents([.day], from: firstDate, to: lastDate)
return components.day!
}
与日月份的组成部分进行比较的另一种方法
用法：
以下列格式输入日期
[dd, mm, yyyy]
[9, 6, 2017]
[6, 6, 2017]
答案 10 :(得分：0)
针对Swift 3进行了更新：
如果您要打印两个日历日期之间的天数和天数列表，请使用以下简单代码;
//变量声明：
var daysListArray = [String]()
//功能定义：
func printCountBtnTwoDates(mStartDate: Date, mEndDate: Date) -> Int {
let calendar = Calendar.current
let formatter = DateFormatter()
var newDate = mStartDate
daysListArray.removeAll()
while newDate <= mEndDate {
formatter.dateFormat = "yyyy-MM-dd"
daysListArray.append(formatter.string(from: newDate))
newDate = calendar.date(byAdding: .day, value: 1, to: newDate)!
}
// print("daysListArray: \(daysListArray)") // if you want to print list between start date and end date
return daysListArray.count
}
//调用上述功能：
let count = self.printCountBtnTwoDates(mStartDate: your_start_date, mEndDate: your_end_date)
print("count: \(count)") // date count
//享受编码......！