如何在日历中使用 NSCalendar 范围功能？

Question

我有以下代码在 Swift 2 中使用编译，但在 Swift 4.2 中不会。返回布尔值的范围函数不再是 Calendar 数据类型的一部分，而是 NSCalendar 数据类型的一部分。有没有办法可以使用或格式化此函数以使其在 Swift 4.2 中编译？

extension Calendar {
    /**
     Returns a tuple containing the start and end dates for the week that the
     specified date falls in.
     */
    func weekDatesForDate(date: NSDate) -> (start: NSDate, end: NSDate) {
        var interval: TimeInterval = 0
        var start: NSDate?
        range(of: .weekOfYear, start: &start, interval: &interval, for: date as Date)
        let end = start!.addingTimeInterval(interval)

        return (start!, end)
    }
}

我尝试了以下方法，但是范围函数不一样并且无法编译：

extension NSCalendar {
    /**
     Returns a tuple containing the start and end dates for the week that the
     specified date falls in.
     */
    func weekDatesForDate(date: NSDate) -> (start: NSDate, end: NSDate) {
        var interval: TimeInterval = 0
        var start: NSDate?
        range(of: .weekOfYear, start: &start, interval: &interval, for: date as Date)
        let end = start!.addingTimeInterval(interval)

        return (start!, end)
    }
}

Answer 1

Calendar 中的range(of:start:interval:for:) 等价于dateInterval(of:start:interval:for:)

不要在 Swift 中使用 NSDate

extension Calendar {
    /**
     Returns a tuple containing the start and end dates for the week that the
     specified date falls in.
     */
    func weekDatesForDate(date: Date) -> (start: Date, end: Date) {
        var interval: TimeInterval = 0
        var start = Date()
        dateInterval(of: .weekOfYear, start: &start, interval: &interval, for: date)
        let end = start.addingTimeInterval(interval)

        return (start, end)
    }
}

我建议使用专用的DateInterval 作为返回值而不是元组：

extension Calendar {
    /**
     Returns a tuple containing the start and end dates for the week that the
     specified date falls in.
     */
    func weekDatesForDate(date: Date) -> DateInterval {
        var interval: TimeInterval = 0
        var start = Date()
        dateInterval(of: .weekOfYear, start: &start, interval: &interval, for: date)
        let end = start.addingTimeInterval(interval)
        return DateInterval(start: start, end: end)
    }
}