Ios 如何使用NSUserDefaults保存NSTimer？敏捷的

我想使用NSUserDefaults保存一个计时器以实现我的目标。不幸的是，当我尝试使用NSUserDefaults保存NSDate（）时，它会变成静态的，并且不会继续计数。我做错什么了吗？同样，我的目标是让计时器仍然工作，不管它是进入后台还是被终止。它应该保存当前时间，并将其与剩余时间进行比较。这是到目前为止我的代码。解决此问题的其他代码在OBJ C中，并在后台使用，这是不必要的

func startTimer() {
    // then set time interval to expirationDate…

    expirationDate = NSDate(timeIntervalSinceNow: 86400 )
    dateTimer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(QOTDVC.updateUI(timer:)), userInfo: nil, repeats: true)
    RunLoop.current.add(dateTimer, forMode: RunLoopMode.commonModes)
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "TimerAdded"), object: nil)

}

func updateUI(timer: Timer)
{
    // Call the currentTimeString method which can decrease the time..
    let timeString = currentTimeString()
    timerLabel.text = "\(timeString)"
}
func currentTimeString() -> DateComponents  {
    let unitFlags: Set<Calendar.Component> = [.hour, .minute, .second]



    let countdown: DateComponents = Calendar.current.dateComponents(unitFlags, from: defaults.object(forKey: currentTime.description) as! Date, to: expirationDate as Date)


    print("this is the \(countdown)")

    if countdown.second! > 0 {

    } else {
        dateTimer.invalidate()


    }
        return countdown
}

func startTimer（）{
//然后将时间间隔设置为expirationDate…
expirationDate=NSDate（timeintervalencenow:86400）
dateTimer=Timer.scheduledTimer（时间间隔：1.0，目标：self，选择器：#选择器（QOTDVC.updateUI（计时器：）），userInfo:nil，repeats:true）
RunLoop.current.add（dateTimer，forMode:RunLoopMode.commonModes）
NotificationCenter.default.post（名称：NSNotification.name（rawValue:“timeraded”），对象：nil）
}
func updateUI（计时器：计时器）
{
//调用currentTimeString方法，该方法可以减少时间。。
让timeString=currentTimeString（）
timerLabel.text=“\（timeString）”
}
func currentTimeString（）->DateComponents{
let unitFlags:Set=[.hour、.minute、.second]
让倒计时：DateComponents=Calendar.current.DateComponents（unitFlags，from:defaults.object（forKey:currentTime.description）作为！日期，to:expirationDate作为日期）
打印（“这是\（倒计时）”）
如果倒计时。秒！>0{
}否则{
dateTimer.invalidate（）
}
返回倒计时
}

以下是我的完整代码示例。我希望这就是你想要的

import UIKit

protocol UserDefaultsTimerDelegate {
    func timerAction(timer: Timer, secondsToEnd:Int)
}

class UserDefaultsTimer {

static var delegate: UserDefaultsTimerDelegate?

class var timerEndDate: Date? {
    get {
        return UserDefaults.standard.value(forKey: "timerEndDate") as! Date?
    }
    set (newValue) {
        UserDefaults.standard.setValue(newValue, forKey: "timerEndDate")
    }
}

class var timerInited: Bool {
    get {
        if let _ = timerEndDate {
            return true
        } else {
            return false
        }
    }
}

class func setTimer(date: Date, setDateOnlyIfCurrenTimerIsOver: Bool) {
    if !setDateOnlyIfCurrenTimerIsOver {
        timerEndDate = date
    } else {
        if !timerInited {
            timerEndDate = date
        } else {
            let difference = timerEndDate!.seconds(from: Date())
            if (difference <= 0) {
                timerEndDate = date
            }
        }
    }
}

class func resetTimer() {
     timerEndDate = nil
}

class func resumeTimer() {
    if timerInited {
        NSLog("timer end date:\(timerEndDate)")
        let timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(action(timer:)), userInfo: nil, repeats: true)
        RunLoop.current.add(timer, forMode: RunLoopMode.commonModes)
    }
}

@objc class func action(timer: Timer) {
    if let timerEndDate = timerEndDate {

        let difference = timerEndDate.seconds(from: timer.fireDate)
        if let delegate = delegate {
            delegate.timerAction(timer: timer, secondsToEnd: difference)
        }

        NSLog("timer: \(difference)")
        if (difference <= 0) {
            timer.invalidate()
            resetTimer()
        }
    } else {
        timer.invalidate()
        resetTimer()
    }
}
}

extension Date {
/// Returns the amount of years from another date
func years(from date: Date) -> Int {
    return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
}
/// Returns the amount of months from another date
func months(from date: Date) -> Int {
    return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
}
/// Returns the amount of weeks from another date
func weeks(from date: Date) -> Int {
    return Calendar.current.dateComponents([.weekOfYear], from: date, to: self).weekOfYear ?? 0
}
/// Returns the amount of days from another date
func days(from date: Date) -> Int {
    return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
}
/// Returns the amount of hours from another date
func hours(from date: Date) -> Int {
    return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
}
/// Returns the amount of minutes from another date
func minutes(from date: Date) -> Int {
    return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
}
/// Returns the amount of seconds from another date
func seconds(from date: Date) -> Int {
    return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
}
/// Returns the a custom time interval description from another date
func offset(from date: Date) -> String {
    if years(from: date)   > 0 { return "\(years(from: date))y"   }
    if months(from: date)  > 0 { return "\(months(from: date))M"  }
    if weeks(from: date)   > 0 { return "\(weeks(from: date))w"   }
    if days(from: date)    > 0 { return "\(days(from: date))d"    }
    if hours(from: date)   > 0 { return "\(hours(from: date))h"   }
    if minutes(from: date) > 0 { return "\(minutes(from: date))m" }
    if seconds(from: date) > 0 { return "\(seconds(from: date))s" }
    return ""
}
}

class ViewController: UIViewController, UserDefaultsTimerDelegate {

var label = UILabel(frame: CGRect(x: 40, y: 40, width: 60, height: 20))

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    label.text = ""
    label.textColor = UIColor.black
    view.addSubview(label)
    UserDefaultsTimer.delegate = self
    UserDefaultsTimer.setTimer(date: Date(timeIntervalSinceNow: 50), setDateOnlyIfCurrenTimerIsOver: true)
    UserDefaultsTimer.resumeTimer()
}

func timerAction(timer: Timer, secondsToEnd: Int) {
    label.text = "\(secondsToEnd)"
}
}

导入UIKit
协议UserDefaultsTimerDelegate{
func timerAction（计时器：计时器，秒结束：Int）
}
类UserDefaultsTimer{
静态变量委托：UserDefaultsTimerDelegate？
类变量timerEndDate:日期{
得到{
将UserDefaults.standard.value（forKey:“timerEndDate”）返回为！Date？
}
设置（新值）{
UserDefaults.standard.setValue（newValue，forKey:“timerEndDate”）
}
}
类变量timerInited:Bool{
得到{
如果let=timerEndDate{
返回真值
}否则{
返回错误
}
}
}
类func setTimer（日期：date，setdateonlyfcurrentimerisover:Bool）{
如果！setDateOnlyIfCurrenTimerIsOver{
timerEndDate=日期
}否则{
如果！时间限制{
timerEndDate=日期
}否则{
让差异=timerEndDate！。秒（从：日期（））
if（差分Int）{
返回Calendar.current.dateComponents（[.month]，from:date，to:self）。月份？？0
}
///返回从另一个日期算起的周数
func周数（从日期开始：日期）->Int{
返回Calendar.current.dateComponents（[.weekOfYear]，from:date，to:self）。weekOfYear？？0
}
///返回从另一个日期算起的天数
func天（从日期开始：日期）->Int{
返回Calendar.current.dateComponents（[.day]，from:date，to:self）.day±0
}
///返回从另一个日期算起的小时数
func小时数（从日期开始：日期）->Int{
返回Calendar.current.dateComponents（[.hour]，from:date，to:self）.hour±0
}
///返回从另一个日期算起的分钟数
func分钟数（从日期开始：日期）->Int{
返回Calendar.current.dateComponents（[.minute]，from:date，to:self）。分钟？？0
}
///返回从另一个日期算起的秒数
func秒（从日期开始：日期）->Int{
返回Calendar.current.dateComponents（[.second]，from:date，to:self）.second±0
}
///返回从另一个日期开始的自定义时间间隔说明
func偏移量（从日期：日期）->字符串{
如果年（自：日期）>0{返回“\（年（自：日期））y”}
如果月份（从：日期起）>0{return“\（月份（从：日期起））M”}
如果周数（从：日期）>0{return“\（周数（从：日期））w”}
如果天（从：日期）>0{return“\（天（从：日期））d”}
如果小时数（从：日期）>0{返回“\（小时数（从：日期））h”}
如果分钟数（从：日期）>0{return“\（分钟数（从：日期））m”}
如果秒数（从：日期）>0{返回“\（秒数（从：日期））s”}
返回“”
}
}
类ViewController:UIViewController，UserDefaultsTimerDelegate{
var label=UILabel（帧：CGRect（x:40，y:40，宽度：60，高度：20））
重写func viewDidLoad（）{
super.viewDidLoad（）
//加载视图后，通常从nib执行任何其他设置。
label.text=“”
label.textColor=UIColor.black
view.addSubview（标签）
UserDefaultsTimer.delegate=self
UserDefaultsTimer.setTimer（日期：日期（timeIntervalSinceNow:50），setDateOnlyIfCurrenTimerIsOver:true）
UserDefaultsTimer.resumeTimer（）
}
func timerAction（计时器：计时器，秒结束：Int）{
label.text=“\（secondsToEnd）”
}
}

这是我的完整代码示例。我希望这是您想要的

import UIKit

protocol UserDefaultsTimerDelegate {
    func timerAction(timer: Timer, secondsToEnd:Int)
}

class UserDefaultsTimer {

static var delegate: UserDefaultsTimerDelegate?

class var timerEndDate: Date? {
    get {
        return UserDefaults.standard.value(forKey: "timerEndDate") as! Date?
    }
    set (newValue) {
        UserDefaults.standard.setValue(newValue, forKey: "timerEndDate")
    }
}

class var timerInited: Bool {
    get {
        if let _ = timerEndDate {
            return true
        } else {
            return false
        }
    }
}

class func setTimer(date: Date, setDateOnlyIfCurrenTimerIsOver: Bool) {
    if !setDateOnlyIfCurrenTimerIsOver {
        timerEndDate = date
    } else {
        if !timerInited {
            timerEndDate = date
        } else {
            let difference = timerEndDate!.seconds(from: Date())
            if (difference <= 0) {
                timerEndDate = date
            }
        }
    }
}

class func resetTimer() {
     timerEndDate = nil
}

class func resumeTimer() {
    if timerInited {
        NSLog("timer end date:\(timerEndDate)")
        let timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(action(timer:)), userInfo: nil, repeats: true)
        RunLoop.current.add(timer, forMode: RunLoopMode.commonModes)
    }
}

@objc class func action(timer: Timer) {
    if let timerEndDate = timerEndDate {

        let difference = timerEndDate.seconds(from: timer.fireDate)
        if let delegate = delegate {
            delegate.timerAction(timer: timer, secondsToEnd: difference)
        }

        NSLog("timer: \(difference)")
        if (difference <= 0) {
            timer.invalidate()
            resetTimer()
        }
    } else {
        timer.invalidate()
        resetTimer()
    }
}
}

extension Date {
/// Returns the amount of years from another date
func years(from date: Date) -> Int {
    return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
}
/// Returns the amount of months from another date
func months(from date: Date) -> Int {
    return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
}
/// Returns the amount of weeks from another date
func weeks(from date: Date) -> Int {
    return Calendar.current.dateComponents([.weekOfYear], from: date, to: self).weekOfYear ?? 0
}
/// Returns the amount of days from another date
func days(from date: Date) -> Int {
    return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
}
/// Returns the amount of hours from another date
func hours(from date: Date) -> Int {
    return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
}
/// Returns the amount of minutes from another date
func minutes(from date: Date) -> Int {
    return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
}
/// Returns the amount of seconds from another date
func seconds(from date: Date) -> Int {
    return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
}
/// Returns the a custom time interval description from another date
func offset(from date: Date) -> String {
    if years(from: date)   > 0 { return "\(years(from: date))y"   }
    if months(from: date)  > 0 { return "\(months(from: date))M"  }
    if weeks(from: date)   > 0 { return "\(weeks(from: date))w"   }
    if days(from: date)    > 0 { return "\(days(from: date))d"    }
    if hours(from: date)   > 0 { return "\(hours(from: date))h"   }
    if minutes(from: date) > 0 { return "\(minutes(from: date))m" }
    if seconds(from: date) > 0 { return "\(seconds(from: date))s" }
    return ""
}
}

class ViewController: UIViewController, UserDefaultsTimerDelegate {

var label = UILabel(frame: CGRect(x: 40, y: 40, width: 60, height: 20))

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    label.text = ""
    label.textColor = UIColor.black
    view.addSubview(label)
    UserDefaultsTimer.delegate = self
    UserDefaultsTimer.setTimer(date: Date(timeIntervalSinceNow: 50), setDateOnlyIfCurrenTimerIsOver: true)
    UserDefaultsTimer.resumeTimer()
}

func timerAction(timer: Timer, secondsToEnd: Int) {
    label.text = "\(secondsToEnd)"
}
}

导入UIKit
协议UserDefaultsTimerDelegate{
func timerAction（计时器：计时器，秒结束：Int）
}
类UserDefaultsTimer{
静态变量委托：UserDefaultsTimerDelegate？
类变量timerEndDate:日期{
得到{
将UserDefaults.standard.value（forKey:“timerEndDate”）返回为！Date？
}
设置（新值）{
UserDefaults.standard.setValue（newValue，forKey:“timerEndDate”）
}
}
类变量timerInited:Bool{
得到{
如果let=timerEndDate{
返回真值
}否则{
返回错误
}
}
}
类func setTimer（日期：date，setdateonlyfcurrentimerisover:Bool）{
如果！setDateOnlyIfCurrenTimerIsOver{
timerEndDate=日期
}否则{
如果！时间限制{
timerEndDate=日期
}否则{
让差异=timerEndDate！。秒（从：日期（））
if（差分Int）{
返回Calendar.current.dateComponents（[.month]，from:date，to:self）。月份？？0
}
///返回从另一个日期算起的周数
func周数（从日期开始：日期）->Int{
返回Calendar.current.dateComponents（[.we