ios - Swift 显示时间从 Date (NSDate) 开始

Question

在一个单元格中，我想显示来自 Parse 服务器中 NSDate 的时间。这是代码，但它不起作用。什么都没有改变，数据也没有被解析。

    if let createdat = (object?["createdAt"] as? String){
            let pastDate = Date(timeIntervalSinceNow: TimeInterval(createdat)!)
            cell.TimeAgo.text = pastDate.timeAgoDisplay()
        }


       extension Date {
          func timeAgoDisplay() -> String {
        let secondsAgo = Int(Date().timeIntervalSince(self))

        let minute = 60
        let hour = 60 * minute
        let day = 24 * hour
        let week = 7 * day

        if secondsAgo < minute {
            return "\(secondsAgo) sec ago"
        } else if secondsAgo < hour {
            return "\(secondsAgo / minute) min ago"
        } else if secondsAgo < day {
            return "\(secondsAgo / hour) hrs ago"
        } else if secondsAgo < week {
            return "\(secondsAgo / day) days ago"
        }

        return "\(secondsAgo / week) weeks ago"
    }
}

Answer 1

If you just want a Time Ago extension for Date go to the bottom of the answer 😊

我将向您展示一个示例，只是为了在几秒钟前和之后显示您的扩展更新。

注意:如果需要，您可以直接使用 Pase 中的日期:

if let pastDate = (object?["createdAt"] as? Date) {
    cell.TimeAgo.text = pastDate.timeAgoDisplay()
}

自 Swift 5.1

如何使用 Swift 5.1 显示秒前的示例:

自 iOS13 Apple 引入了一个新类 RelativeDateTimeFormatter

extension Date {
    func timeAgoDisplay() -> String {
        let formatter = RelativeDateTimeFormatter()
        formatter.unitsStyle = .full
        return formatter.localizedString(for: self, relativeTo: Date())
    }
}

这个类将允许你根据你的语言获得一个时间之前的字符串。它会根据您的间隔自动选择正确的时间单位，这是一个示例:

|--------------------------|------------------|
| Time interval in seconds |      Display     |
|--------------------------|------------------|
|             -6           |   6 seconds ago  |
|            -60           |   1 minute ago   |
|           -600           |  10 minutes ago  |
|          -6000           |    1 hour ago    |
|         -60000           |   16 hours ago   |
|--------------------------|------------------|

您会注意到它会自动为您处理复数。

Swift 3 或 Swift 4

如何使用 Swift 3 或 Swift 4 获取秒前的示例:

首先:要获得秒数之前，我们需要检查是否有一分钟或更短的时间，要获得当前日期减去一分钟，您可以这样写:

let minuteAgo = calendar.date(byAdding: .minute, value: -1, to: Date())!

第二:现在比较两个日期! (如果是您的扩展，我们会自行替换 yourDate)并获取这 2 个日期之间的差异。

if (minuteAgo < yourDate) {
    let diff = Calendar.current.dateComponents([.second], from: yourDate, to: Date()).second ?? 0
    print("\(diff) sec ago")
}

就这样，现在你可以打印时间了!

所以你的扩展是这样的: (这是获取时间的简单扩展)

extension Date {
    func timeAgoDisplay() -> String {
 
        let calendar = Calendar.current
        let minuteAgo = calendar.date(byAdding: .minute, value: -1, to: Date())!
        let hourAgo = calendar.date(byAdding: .hour, value: -1, to: Date())!
        let dayAgo = calendar.date(byAdding: .day, value: -1, to: Date())!
        let weekAgo = calendar.date(byAdding: .day, value: -7, to: Date())!

        if minuteAgo < self {
            let diff = Calendar.current.dateComponents([.second], from: self, to: Date()).second ?? 0
            return "\(diff) sec ago"
        } else if hourAgo < self {
            let diff = Calendar.current.dateComponents([.minute], from: self, to: Date()).minute ?? 0
            return "\(diff) min ago"
        } else if dayAgo < self {
            let diff = Calendar.current.dateComponents([.hour], from: self, to: Date()).hour ?? 0
            return "\(diff) hrs ago"
        } else if weekAgo < self {
            let diff = Calendar.current.dateComponents([.day], from: self, to: Date()).day ?? 0
            return "\(diff) days ago"
        }
        let diff = Calendar.current.dateComponents([.weekOfYear], from: self, to: Date()).weekOfYear ?? 0
        return "\(diff) weeks ago"
    }
}

要使用它，这非常简单:

var now = Date()
now.timeAgoDisplay()