Question

我试图计算从现在起（即日期（））到下一个下午5点的时间。

如果当前时间是下午3点，则输出为02:00:00。（在HH：MM：SS）

如果当前时间是下午6点，则输出将是23:00:00。（直到下午5点！）

我如何在Swift 3中做到这一点？

感谢。

Answer 1

您可以使用Calendar.nextDate查找即将到来的下午5点的日期。

let now = Date()
let calendar = Calendar.current
let components = DateComponents(calendar: calendar, hour: 17)  // <- 17:00 = 5pm
let next5pm = calendar.nextDate(after: now, matching: components, matchingPolicy: .nextTime)!

然后，使用dateComponents(_:from:to:)计算next5pm和now之间的差异。

let diff = calendar.dateComponents([.hour, .minute, .second], from: now, to: next5pm)
print(diff)
// Example outputs:
//  hour: 2 minute: 21 second: 39 isLeapMonth: false 
//  hour: 23 minute: 20 second: 10 isLeapMonth: false

Answer 2

func tommorrow5() ->Date {
var todayAt5 = Calendar.current.dateComponents([.year,.month,.day,.hour], from: Date() )
todayAt5.hour = 17
let dateToDisplay = Calendar.current.date(from: todayAt5)
return Calendar.current.date(byAdding: .day , value: 1, to: dateToDisplay!)! }


func showTimeDifference()->DateComponents{
var todayAt5 = Calendar.current.dateComponents([.year,.month,.day,.hour], from: Date() )
todayAt5.hour = 17
let dateToDisplay = Calendar.current.date(from: todayAt5)
let now = Date()
switch now.compare(dateToDisplay!) {

case .orderedAscending : // now is earlier than 5pm

    return Calendar.current.dateComponents([Calendar.Component.hour, Calendar.Component.minute, Calendar.Component.second], from: Date(), to: dateToDisplay!)

case .orderedDescending : // now is later than 5 pm

    return Calendar.current.dateComponents([Calendar.Component.hour, Calendar.Component.minute, Calendar.Component.second], from: Date(), to: tommorrow5())
case .orderedSame : break // now is 5 pm
}


return Calendar.current.dateComponents([Calendar.Component.hour, Calendar.Component.minute, Calendar.Component.second], from: Date(), to: dateToDisplay!)

}

你可以像这样使用它它将返回到今天下午5点如果它已经过了下午5点将返回到明天下午5点

showTimeDifference()

斯威夫特：从当前时间倒计时到一定时间

2 个答案: