如果日期是月初，则获取当前周的所有日期返回不正确

Posted 2023-03-12

【中文标题】如果日期是月初，则获取当前周的所有日期返回不正确

【英文标题】：Get all dates for current week returns incorrect if the date is beginning of a month

【发布时间】：2016-07-27 20:43:35

【问题描述】：

这是我在网上找到的代码，用于根据今天的日期获取本周的所有日期。如果日期是月初，例如 2016 年 9 月 1 日星期四，则该周从 星期四 开始，并在 2016 年 9 月 7 日星期三。这真的很困扰我，因为如果日期是月底； 2016 年 7 月 31 日星期日 然后它将在该周的 星期一 开始并在 星期日 结束，这正是我想要的。

这可能是重复的，但我花了一段时间查看类似的问题，但我仍然卡住了。

编辑： 有没有办法根据当前日期返回当前一周的所有日期？（如果你有时间，下周也是如此？）

func formatDate(date: NSDate) -> String 
    let format = "EEEE MMMM dd yyyy"
    let formatter = NSDateFormatter()
    formatter.dateFormat = format
    return formatter.stringFromDate(date)


// =======================================================================//
//                 THIS WEEK DATES                                        //
// =======================================================================//
func formattedDaysInThisWeek() -> [String] 
    // create calendar
    let calendar = NSCalendar(identifier: NSCalendarIdentifierGregorian)!

    // today's date
    let today = NSDate()
    let todayComponent = calendar.components([.Day, .Month, .Year], fromDate: today)
    let components = calendar.components([.Weekday], fromDate: today)



    // range of dates in this week
    let thisWeekDateRange = calendar.rangeOfUnit(.Day, inUnit:.WeekOfMonth, forDate:today)


    // date interval from today to beginning of week
    let dayInterval = thisWeekDateRange.location - todayComponent.day
    print(thisWeekDateRange.location)
    print(todayComponent.day)


    // date for beginning day of this week, ie. this week's Sunday's date

    if components.weekday == 1 
        print("Is a sunday")
        let beginningOfWeek = calendar.dateByAddingUnit(.Day, value: -6, toDate: today, options: .MatchNextTime)

        var formattedDays: [String] = []

        for i in 0 ..< 7 
            let date = calendar.dateByAddingUnit(.Day, value: i, toDate: beginningOfWeek!, options: .MatchNextTime)!
            formattedDays.append(formatDate(date))

        
        return formattedDays
     else 
        print("Not a sunday")
        let beginningOfWeek = calendar.dateByAddingUnit(.Day, value: dayInterval, toDate: today, options: .MatchNextTime)

        var formattedDays: [String] = []

        for i in 1 ..< thisWeekDateRange.length + 1 
            let date = calendar.dateByAddingUnit(.Day, value: i, toDate: beginningOfWeek!, options: .MatchNextTime)!
            formattedDays.append(formatDate(date))

        

        return formattedDays
    

【参考方案1】：

此解决方案检查当前日期是否为星期一。

如果是，这是一周的开始，如果否，回到过去的星期一。

它还使用formatDate 函数。

func formattedDaysInThisWeek() -> [String] 
    // create calendar
    let calendar = Calendar(identifier: .gregorian)

    // today's date
    let today = Date()

    let weekday = calendar.component(.weekday, from: today)
    let beginningOfWeek : Date
    if weekday != 2  // if today is not Monday, get back
        let weekDateConponent = DateComponents(weekday: 2)
        beginningOfWeek = calendar.nextDate(after: today, matching: weekDateConponent, matchingPolicy: .nextTime, direction: .backward)!

     else  // today is Monday
        beginningOfWeek = calendar.startOfDay(for: today)
    
    var formattedDays = [String]()
    for i in 0..<7 
        let date = calendar.date(byAdding: .day, value: i, to: beginningOfWeek)!
        formattedDays.append(formatDate(date))
    
    return formattedDays

【参考方案2】：

我不知道这里是否有实际问题，但我写了一个快速的 sn-p，它总是会给你本周的星期日：

let today = NSDate()
let calendar = NSCalendar(identifier: NSCalendarIdentifierGregorian)!
let todayComps = calendar.components([.Day, .Month, .Year], fromDate: today)
let dayOfWeekComps = calendar.components([.Weekday], fromDate: today)
todayComps.day -= (dayOfWeekComps.weekday - 1)
let sunday = calendar.dateFromComponents(todayComps)