如何检查时间是否在swift的特定范围内

Question

嗨,我想检查当前时间是否在一个时间范围内,比如8:00 - 16:30.我的代码显示我可以将当​​前时间作为字符串获取,但我不确定如何使用此值来检查它是否在上面指定的时间范围内.任何帮助将不胜感激!

var todaysDate:NSDate = NSDate()
var dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "HH:mm"
var dateInFormat:String = dateFormatter.stringFromDate(todaysDate)
println(dateInFormat) // 23:54

Answer 1

有很多方法可以做到这一点.就个人而言,我不喜欢使用字符串,如果我可以避免它.我宁愿处理日期组件.

下面是一些操场代码,它使用Calendar对象获取当前日期的日/月/年,并添加所需的小时/分钟组件,然后为这些组件生成日期.

它创建8:00和16:30的日期,然后比较日期以查看当前日期/时间是否在该范围内.

它比其他人的代码更长,但我认为值得学习如何使用日历进行日期计算:

编辑#3:

这个答案来自很久以前.我将在下面留下旧的答案,但这是目前的解决方案:

@CodenameDuchess的回答使用系统函数, date(bySettingHour:minute:second:of:matchingPolicy:repeatedTimePolicy:direction:)

使用该函数,代码可以简化为:

import UIKit

let calendar = Calendar.current
let now = Date()
let eight_today = calendar.date(
  bySettingHour: 8,
  minute: 0,
  second: 0,
  of: now)!

let four_thirty_today = calendar.date(
  bySettingHour: 16,
  minute: 30,
  second: 0,
  of: now)!

if now >= eight_today &&
  now <= four_thirty_today
{
  print("The time is between 8:00 and 16:30")
}

以下是旧的(Swift 2)答案,历史完整性:

import UIKit
//-------------------------------------------------------------
//NSDate extensions.
extension NSDate
{
  /**
  This adds a new method dateAt to NSDate.

  It returns a new date at the specified hours and minutes of the receiver

  :param: hours: The hours value
  :param: minutes: The new minutes

  :returns: a new NSDate with the same year/month/day as the receiver, but with the specified hours/minutes values
  */
  func dateAt(#hours: Int, minutes: Int) -> NSDate
  {
    let calendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!

    //get the month/day/year componentsfor today's date.

    println("Now = \(self)")

    let date_components = calendar.components(
      NSCalendarUnit.CalendarUnitYear |
        NSCalendarUnit.CalendarUnitMonth |
        NSCalendarUnit.CalendarUnitDay,
      fromDate: self)

    //Create an NSDate for 8:00 AM today.
    date_components.hour = hours
    date_components.minute = minutes
    date_components.second = 0

    let newDate = calendar.dateFromComponents(date_components)!
        return newDate
  }
}
//-------------------------------------------------------------
//Tell the system that NSDates can be compared with ==, >, >=, <, and <= operators
extension NSDate: Equatable {}
extension NSDate: Comparable {}

//-------------------------------------------------------------
//Define the global operators for the 
//Equatable and Comparable protocols for comparing NSDates

public func ==(lhs: NSDate, rhs: NSDate) -> Bool
{
  return lhs.timeIntervalSince1970 == rhs.timeIntervalSince1970
}

public func <(lhs: NSDate, rhs: NSDate) -> Bool
{
  return lhs.timeIntervalSince1970 < rhs.timeIntervalSince1970
}
public func >(lhs: NSDate, rhs: NSDate) -> Bool
{
  return lhs.timeIntervalSince1970 > rhs.timeIntervalSince1970
}
public func <=(lhs: NSDate, rhs: NSDate) -> Bool
{
  return lhs.timeIntervalSince1970 <= rhs.timeIntervalSince1970
}
public func >=(lhs: NSDate, rhs: NSDate) -> Bool
{
  return lhs.timeIntervalSince1970 >= rhs.timeIntervalSince1970
}
//-------------------------------------------------------------

let now = NSDate()
let eight_today = now.dateAt(hours: 8, minutes: 0)
let four_thirty_today = now.dateAt(hours:16, minutes: 30)

if now >= eight_today &&
  now <= four_thirty_today
{
  println("The time is between 8:00 and 16:30")
}

编辑:

这个答案中的代码改变了很多Swift 3.

而不是使用的NSDate,它更有意义,我们本地Date的对象,Date对象是Equatable和Comparable"开箱即用".

因此,我们可以摆脱的Equatable和Comparable扩展以及定义<,>和=运营商.

然后我们需要对dateAt函数中的语法进行大量调整,以遵循Swift 3语法.新的扩展在Swift 3中看起来像这样:

Swift 3版本:

import Foundation

extension Date
{

  func dateAt(hours: Int, minutes: Int) -> Date
  {
    let calendar = NSCalendar(calendarIdentifier: NSCalendar.Identifier.gregorian)!

    //get the month/day/year componentsfor today's date.


    var date_components = calendar.components(
      [NSCalendar.Unit.year,
       NSCalendar.Unit.month,
       NSCalendar.Unit.day],
      from: self)

    //Create an NSDate for the specified time today.
    date_components.hour = hours
    date_components.minute = minutes
    date_components.second = 0

    let newDate = calendar.date(from: date_components)!
    return newDate
  }
}


let now = Date()
let eight_today = now.dateAt(hours: 8, minutes: 0)
let four_thirty_today = now.dateAt(hours: 16, minutes: 30)

if now >= eight_today &&
  now <= four_thirty_today
{
  print("The time is between 8:00 and 16:30")
}

Answer 2

在Swift 3.0中,您可以使用新的Date值类型并直接与==,>,<etc进行比较

    let now = NSDate()
    let nowDateValue = now as Date
    let todayAtSevenAM = calendar.date(bySettingHour: 7, minute: 0, second: 0, of: nowDateValue, options: [])
    let todayAtTenPM = calendar.date(bySettingHour: 22, minute: 0, second: 0, of: nowDateValue, options: [])

    if nowDateValue >= todayAtSevenAM! &&
        nowDateValue <= todayAtTenPM!
    {
        // date is in range

    }

非常方便.

Answer 3

您可以从今天的日期获取年、月和日，将它们附加到这些日期时间字符串以构建新Date对象。然后compare将todaysDate这些两个结果Date的对象：

let todaysDate  = Date()
let startString = "8:00"
let endString   = "16:30"

// convert strings to `Date` objects

let formatter = DateFormatter()
formatter.dateFormat = "HH:mm"
let startTime = formatter.date(from: startString)
let endTime = formatter.date(from: endString)

// extract hour and minute from those `Date` objects

let calendar = Calendar.current

var startComponents = calendar.dateComponents([.hour, .minute], from: startTime!)
var endComponents = calendar.dateComponents([.hour, .minute], from: endTime!)

// extract day, month, and year from `todaysDate`

let nowComponents = calendar.dateComponents([.month, .day, .year], from: todaysDate)

// adjust the components to use the same date

startComponents.year  = nowComponents.year
startComponents.month = nowComponents.month
startComponents.day   = nowComponents.day

endComponents.year  = nowComponents.year
endComponents.month = nowComponents.month
endComponents.day   = nowComponents.day

// combine hour/min from date strings with day/month/year of `todaysDate`

guard
    let startDate = calendar.date(from: startComponents),
    let endDate = calendar.date(from: endComponents)
else {
    print("unable to create dates")
    return
}

// now we can see if today's date is inbetween these two resulting `NSDate` objects

let isInRange = todaysDate > startDate && todaysDate < endDate

有关Swift 2 答案，请参阅此答案的先前修订版。

Answer 4

以下解决方案从系统获取当前时间，然后检查它是否存在该范围。在我的情况下，时间范围是上午 8:00 到下午 5:00 适用于 Swift 4.2 的解决方案

 func CheckTime()->Bool{
    var timeExist:Bool
    let calendar = Calendar.current
    let startTimeComponent = DateComponents(calendar: calendar, hour:8)
    let endTimeComponent   = DateComponents(calendar: calendar, hour: 17, minute: 00)

    let now = Date()
    let startOfToday = calendar.startOfDay(for: now)
    let startTime    = calendar.date(byAdding: startTimeComponent, to: startOfToday)!
    let endTime      = calendar.date(byAdding: endTimeComponent, to: startOfToday)!

    if startTime <= now && now <= endTime {
        print("between 8 AM and 5:30 PM")
        timeExist = true
    } else {
        print("not between 8 AM and 5:30 PM")
        timeExist = false
    }
    return timeExist
}