Swift 中具有正确时区的日期范围

Question

我知道有很多关于时区和日期的问题，但我真的很难弄清楚。

我的时区是 GMT+3（这是我的物理设备所说的）

我正在尝试从周日开始获取下周的范围。 所以它需要是 9 月 27 日 ... 10 月 3 日

每天晚上 09:PM 我得到的结果是从 9 月 28 日到 10 月 4 日。 一直保持到凌晨 03:00

我写这个问题的当前时间是凌晨 2 点，它显示了从 9 月 28 日开始的这个范围。

我为Date 做了一个扩展并添加了这个变量（我也在使用 SwiftDate）。

var closedRange: ClosedRange<Date> {
        let d = Date() //.timeInterval - Fix the problem until 03:AM
        let calendar = Calendar.autoupdatingCurrent
        let min = calendar.date(byAdding: .day, value: 0, to: d.nextWeekday(.sunday))!
        let max = calendar.date(byAdding: .day, value: 6, to: d.nextWeekday(.sunday))!
        return min...max
    }

如果我将此变量添加到d，则日期是正确的。但在凌晨 3:AM 之后又搞砸了。

var timeInterval: Date{
        var date = self
        date.addTimeInterval(TimeInterval(TimeZone.current.secondsFromGMT(for: self)))
        return date
    }

稍后查看：

let range = Date().closedRange
    
DatePicker(LocalizedStringKey("Choose day:"), selection: $shift.date, in: range, displayedComponents: .date)

当我将下周作为 String 或 Int 时，也会出现问题。 它从 9 月 28 日开始，而不是 9 月 27 日（再次取决于我的位置时间）

var nextWeek: [String]{
        
        let d = Date()
        var daysArr = [String]()
        let dateFormat = DateFormatter()
        let calendar = Calendar.autoupdatingCurrent
        let dayOfWeek = calendar.component(.weekday, from: d.nextWeekday(.sunday))
        let weekdays = calendar.range(of: .weekday, in: .weekOfYear, for: d.nextWeekday(.sunday))!
        let days = (weekdays.lowerBound ..< weekdays.upperBound).compactMap { calendar.date(byAdding: .day, value: $0 - dayOfWeek, to: d.nextWeekday(.sunday)) }
        
        dateFormat.dateFormat = DateFormats.format11.rawValue
        
        for d in days{
            daysArr.append(dateFormat.string(from: d))
        }
        
        return daysArr
        
    }

同样的问题也发生在这个日期数组上。

var nextWeekAsDates: [Date]{
        
        let d = Date()
        var daysArr = [Date]()
        let calendar = Calendar.autoupdatingCurrent
        let dayOfWeek = calendar.component(.weekday, from: d.nextWeekday(.sunday))
        let weekdays = calendar.range(of: .weekday, in: .weekOfYear, for: d.nextWeekday(.sunday))!
        let days = (weekdays.lowerBound ..< weekdays.upperBound).compactMap { calendar.date(byAdding: .day, value: $0 - dayOfWeek, to: d.nextWeekday(.sunday)) }
                
        for d in days{
            daysArr.append(d)
        }
        
        return daysArr
        
    }

Answer 1

您可以简单地将今天的组件 weekOfYear 提前 1，即 yearForWeekOfYear 并从这些组件中获取日期。那将是下周的开始。如果你需要它的结束，你可以得到下周的开始，这标志着它的结束：

extension Calendar {
    static let gregorian: Calendar = .init(identifier: .gregorian)
}

---

extension Date {
    func nextWeekOfYear(using calendar: Calendar = .gregorian) -> Int {
        calendar.component(.weekOfYear, from: self) + 1
    }
    func yearForWeekOfYear(using calendar: Calendar = .gregorian) -> Int {
        calendar.component(.yearForWeekOfYear, from: self)
    }
    func startOfNextWeek(using calendar: Calendar = .gregorian) -> Date {
        DateComponents(calendar: calendar, weekOfYear: nextWeekOfYear(using: calendar), yearForWeekOfYear: yearForWeekOfYear(using: calendar)).date!
    }
}

---

Date().startOfNextWeek()  // "Sep 27, 2020 at 12:00 AM"

---

如果你需要一个范围：

var range: Range<Date> {
    let min = Date().startOfNextWeek()
    return min..<min.startOfNextWeek()
}

print(range) //  "2020-09-27 03:00:00 +0000..<2020-10-04 03:00:00 +0000\n"