需要把时间转换为：
今天，昨天，1天前，3天前，一周前，两周前，一个月前，三个月前，半年前和一年前
去参考别人已有的库：
swift nsdate lib
malcommac/SwiftDate: Powerful NSDate & Time Zones Management, made in Swift 2
devxoul/Date.swift: A Swift Date Library
最后用如下代码：
基本达到了所需要的效果：
//: Playground – noun: a place where people can play
import UIKit
extension NSDate
{
//2015
var Year: Int {
let curCalendar:NSCalendar = NSCalendar.currentCalendar()
let componentYear:Int = curCalendar.component(NSCalendarUnit.Year, fromDate: self)
return componentYear
}
//11
var Month: Int {
let curCalendar:NSCalendar = NSCalendar.currentCalendar()
let componentMonth:Int = curCalendar.component(NSCalendarUnit.Month, fromDate: self)
return componentMonth
}
//28
var Day: Int {
let curCalendar:NSCalendar = NSCalendar.currentCalendar()
let componentDay:Int = curCalendar.component(NSCalendarUnit.Day, fromDate: self)
return componentDay
}
//10
var Hour: Int {
let curCalendar:NSCalendar = NSCalendar.currentCalendar()
let componentHour:Int = curCalendar.component(NSCalendarUnit.Hour, fromDate: self)
return componentHour
}
//39
var Minute: Int {
let curCalendar:NSCalendar = NSCalendar.currentCalendar()
let componentMinute:Int = curCalendar.component(NSCalendarUnit.Minute, fromDate: self)
return componentMinute
}
//18
var Second: Int {
let curCalendar:NSCalendar = NSCalendar.currentCalendar()
let componentSecond:Int = curCalendar.component(NSCalendarUnit.Second, fromDate: self)
return componentSecond
}
//get short style date time string
//11/28/15, 10:51 AM
func toStringShort() -> String {
let dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.ShortStyle
dateFormatter.timeStyle = NSDateFormatterStyle.ShortStyle
let shortStyleStr:String = dateFormatter.stringFromDate(self)
return shortStyleStr
}
//get medium style date time string
//Nov 28, 2015, 10:51:33 AM
func toStringMedium() -> String {
let dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.MediumStyle
dateFormatter.timeStyle = NSDateFormatterStyle.MediumStyle
let mediumStyleStr:String = dateFormatter.stringFromDate(self)
return mediumStyleStr
}
//get long style date time string
//November 28, 2015 at 10:51:33 AM GMT+8
func toStringLong() -> String {
let dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.LongStyle
dateFormatter.timeStyle = NSDateFormatterStyle.LongStyle
let longStyleStr:String = dateFormatter.stringFromDate(self)
return longStyleStr
}
//get full style date time string
//Saturday, November 28, 2015 at 10:51:33 AM China Standard Time
func toStringFull() -> String {
let dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.FullStyle
dateFormatter.timeStyle = NSDateFormatterStyle.FullStyle
let fullStyleStr:String = dateFormatter.stringFromDate(self)
return fullStyleStr
}
//get date formatted string
//2015/11/28 10:48:12
func toString(dateFormat:String) -> String {
let dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateFormat = dateFormat
let formattedDatetimeStr:String = dateFormatter.stringFromDate(self)
return formattedDatetimeStr
}
//parse input date time string into NSDate
//input: 2015/11/28 12:01:02 and yyyy/MM/dd HH:mm:ss
//output: Optional(2015-11-28 04:01:02 +0000)
static func fromString(datetimeStr:String, dateFormat:String) -> NSDate? {
// print("datetimeStr=\(datetimeStr), dateFormat=\(dateFormat)")
let dateFormatter:NSDateFormatter = NSDateFormatter()
// print("dateFormatter\(dateFormatter)")
dateFormatter.dateFormat = dateFormat
// print("dateFormatter\(dateFormatter)")
let parsedDatetime:NSDate? = dateFormatter.dateFromString(datetimeStr)
// print("parsedDatetime\(parsedDatetime)")
return parsedDatetime
}
//from milli second timestamp to NSDate
static func fromTimestampMsec(timestampInt64InMsec:Int64) -> NSDate {
// print("timestampInt64InMsec=\(timestampInt64InMsec)") //timestampInt64InMsec=1449805150184
let timestampDoubleInSec:Double = Double(timestampInt64InMsec)/1000
// print("timestampDoubleInSec=\(timestampDoubleInSec)") //timestampDoubleInSec=1449805150.184
let parsedDate:NSDate = NSDate(timeIntervalSince1970: NSTimeInterval(timestampDoubleInSec))
// print("parsedDate=\(parsedDate)") //parsedDate=2015-12-11 03:39:10 +0000
return parsedDate
}
//static let emptyDate:NSDate = NSDate(timeIntervalSince1970: 0)
// var emptyDate:NSDate {
// return NSDate(timeIntervalSince1970: 0)
// }
@nonobjc static let emptyDate:NSDate = NSDate(timeIntervalSince1970: 0)
func isToday(toCmpTime:NSDate) -> Bool {
var isToday = false
if (toCmpTime.Year == self.Year) &&
(toCmpTime.Month == self.Month) &&
(toCmpTime.Day == self.Day) {
isToday = true
}
return isToday
}
func toAgoString() -> String {
let curDate = NSDate()
print("self=\(self), curDate=\(curDate)")
let components = self.toDateComponents(curDate)
print("components.year=\(components.year), components.month=\(components.month)")
if components.year > 0 {
// if (components.year >= 1) {
return "一年前"
// }
}
if components.month > 0 {
if (components.month >= 6) && (components.month < 12) {
return "半年前"
} else if (components.month >= 3) && (components.month < 6) {
return "三个月前"
} else if (components.month >= 1) && (components.month < 3) {
return "一个月前"
}
}
if components.day > 0 {
if components.day >= 14 {
return "两周前"
} else if (components.day >= 7) && (components.day < 14) {
return "一周前"
} else if (components.day >= 3) && (components.day < 7) {
return "三天前"
} else if (components.day > 1) && (components.day < 3) {
return "一天前"
} else if components.day == 1 {
return "昨天"
}
} else if components.day == 0 {
return "今天"
}
return ""
}
func toDateComponents(toDate:NSDate) -> NSDateComponents {
let calander = NSCalendar.currentCalendar()
return calander.components([.Second, .Minute, .Hour, .Day, .Month, .Year], fromDate: self, toDate: toDate, options: [])
}
}
public func ==(lhs: NSDate, rhs: NSDate) -> Bool {
return lhs === rhs || lhs.compare(rhs) == .OrderedSame
}
public func <(lhs: NSDate, rhs: NSDate) -> Bool {
return lhs.compare(rhs) == .OrderedAscending
}
extension NSDate: Comparable { }
//let timeToday = NSDate()
////timeToday.toHumanReadableString
//let oneYearAgo = NSDate.fromString("2015-05-12", dateFormat: "yyyy-MM-dd")!
//oneYearAgo.toAgoString()
//let twoYearAgo = NSDate.fromString("2014-06-12", dateFormat: "yyyy-MM-dd")!
////twoYearAgo.toHumanReadableString
//let sixMonthAgo = NSDate.fromString("2015-12-29", dateFormat: "yyyy-MM-dd")!
//sixMonthAgo.toAgoString()
//let threeMonthAgo = NSDate.fromString("2016-02-29", dateFormat: "yyyy-MM-dd")!
//threeMonthAgo.toAgoString()
//let oneMonthAgo = NSDate.fromString("2016-03-29", dateFormat: "yyyy-MM-dd")!
//oneMonthAgo.toAgoString()
//let oneWeekAgo = NSDate.fromString("2016-06-01", dateFormat: "yyyy-MM-dd")!
//oneWeekAgo.toAgoString()
//let threeDayAgo = NSDate.fromString("2016-06-09", dateFormat: "yyyy-MM-dd")!
//threeDayAgo.toAgoString()
//let oneDayAgo = NSDate.fromString("2016-06-12", dateFormat: "yyyy-MM-dd")!
//oneDayAgo.toAgoString()
//let yestodayAgo = NSDate.fromString("2016-06-13", dateFormat: "yyyy-MM-dd")!
//yestodayAgo.toAgoString()
//let todayAgo = NSDate.fromString("2016-06-14", dateFormat: "yyyy-MM-dd")!
//todayAgo.toAgoString()
虽然有点不是足够好：
比如跨年的时候，之前一天，其实输出：昨天
比去年，会更好些。
但是就这么着了。
懒得继续弄了。
后续整理出更通用的代码，详见：
https://github.com/crifan/crifanLib/blob/master/swift/CrifanNSDate.swift
转载请注明：在路上 » ［基本解决］swift中实现时间的人性化描述：多少天前