如何在Swift中使用Calendar nextDate方法查找下一个小时时间

Question

我想找到下一个小时的时间.例如

现在是:4/9/16,10:12:34 AM GMT + 10我想得到:4/9/16,11:00:00 AM GMT + 10

所以我尝试使用Calendar.current.nextDate,但我得到了奇怪的回应.示例代码如下.

let dateFormatter = DateFormatter()
    dateFormatter.dateStyle = .short
    dateFormatter.timeStyle = .long

    var dateComponents = DateComponents()
    dateComponents.minute = 0
    dateComponents.second = 0

    let beginDate = Date(timeIntervalSince1970: 0)
    var beginDateComponents = Calendar.current.dateComponents(in: TimeZone.current, from: beginDate)
    beginDateComponents.minute = 0
    beginDateComponents.second = 0
    let modifiedDate = Calendar.current.date(from: beginDateComponents)!

    let nextHourlyTime = Calendar.current.nextDate(after: modifiedDate, matching: dateComponents, matchingPolicy: .nextTime)!

    print("modifiedDate: \(dateFormatter.string(from: modifiedDate))")
    print("beginDate: \(dateFormatter.string(from: beginDate))")
    print("nextHourlyTime: \(dateFormatter.string(from: nextHourlyTime))")

    /*
     modifiedDate: 1/1/70, 10:00:00 AM GMT+10
     beginDate: 1/1/70, 10:00:00 AM GMT+10
     nextHourlyTime: 1/2/70, 12:00:00 AM GMT+10
     */

但是如果我输入注释代码:"dateComponents.second = 0",那么我将得到正确的答案.

Apple的nextDate api有什么问题吗？

Answer 1

错误发生在您的beginDate.它应该设置为Date()不Date(timeIntervalSince1970: 0).你可以这样做:

extension Date {
    var nextHourShift: Date? {
        return Calendar.current.nextDate(after: self, matching: DateComponents(minute: 0), matchingPolicy: .nextTime)
    }
}

Date().nextHourShift  // "Sep 3, 2016, 4:00 AM"