swift - NSDateFormatter。快速设置自日期以来耗时

Question

我想调用一个函数来检查自日期以来耗时。这将决定 timeLable 如何在我的消息 View Controller 中显示，类似于 IMessage。

我在下面使用的代码只显示 HH:MM

let date = dateFormatter().dateFromString((recent["date"] as? String)!)

timeLabel.text = NSDateFormatter.localizedStringFromDate(date!, dateStyle: NSDateFormatterStyle.NoStyle, timeStyle: NSDateFormatterStyle.NoStyle)

我希望将其更改为以下内容:

• 如果日期是今天，date = "HH:MM"
• 如果日期是昨天，date = "Yesterday"
• 如果date是前天等等，date = "Monday, Tuesday, Wednesday..."
• 如果日期超过 1 周，则日期 = MM/DD/YY

Answer 1

或者试试这个。请注意，我们必须使用 components:fromDate: 然后使用 components:fromDateComponents:toDateComponents:options: 因为如果我们不这样做，昨晚 23:59 将返回 23:59而不是昨天。

extension NSDateFormatter {
    static func friendlyStringForDate(date:NSDate) -> String {
        // Fetch the default calendar
        let calendar = NSCalendar.currentCalendar()

        // Compute components from target date
        let from = calendar.components([.Day, .Month, .Year], fromDate: date)

        // Compute components from current date
        let to = calendar.components([.Day, .Month, .Year], fromDate: NSDate())

        // Compute days difference between the two
        let delta = calendar.components(.Day, fromDateComponents: from, toDateComponents: to, options: [])

        switch delta.day {
        case 0:
            let formatter = NSDateFormatter()
            formatter.timeZone = NSTimeZone.defaultTimeZone()
            formatter.dateFormat = "HH:mm"
            return formatter.stringFromDate(date)

        case 1:
            return "Yesterday"

        case 2..<7:
            let formatter = NSDateFormatter()
            formatter.timeStyle = .NoStyle
            formatter.dateFormat = "EEEE"
            return formatter.stringFromDate(date)

        default:
            let formatter = NSDateFormatter()
            formatter.timeStyle = .NoStyle
             formatter.dateFormat = "MM/dd/YY"
            return formatter.stringFromDate(date)
        }
    }
}

现在，使用它:

timeLabel.text = NSDateFormatter.friendlyStringForDate(date!)