Question

我已经构建了一个CountdownTimer，我想重构成一个单独的类，所以我可以在MainViewController中重用它。我该怎么做呢？

这是我的代码：

var startTime = NSTimeInterval()
var time:Double = 4
var timer = NSTimer()

/* Outlets */
@IBOutlet weak var timerLabel: UILabel!

 /* CountdownTimer function */
func updateTime() {

    var currentTime = NSDate.timeIntervalSinceReferenceDate()
    var elapsedTime = currentTime - startTime
    var seconds = time - elapsedTime

    if seconds > 0 {
        elapsedTime -= NSTimeInterval(seconds)
        timerLabel.text = "\(Int(seconds))"
    } else {
        timer.invalidate()
        timerLabel.fadeOut()
    }
}

func startTimer () {
    if !timer.valid {
        let aSelector : Selector = "updateTime"
        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: aSelector, userInfo: nil, repeats: true)
        startTime = NSDate.timeIntervalSinceReferenceDate()
    }
}

Answer 1

您可以使用闭包：

class MyTimer: NSObject {

    var startTime: NSTimeInterval! = NSTimeInterval()
    var time: Double! = 4
    var timer: NSTimer! = NSTimer()
    var timerEndedCallback: (() -> Void)!
    var timerInProgressCallback: ((elapsedTime: Double) -> Void)!

    func startTimer(timerEnded: () -> Void, timerInProgress: ((elapsedTime: Double) -> Void)!) {
        if !timer.valid {
            let aSelector : Selector = "updateTime"
            timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: aSelector, userInfo: nil, repeats: true)
            startTime = NSDate.timeIntervalSinceReferenceDate()
            timerEndedCallback = timerEnded
            timerInProgressCallback = timerInProgress
        }
    }

     func updateTime() {

        var currentTime = NSDate.timeIntervalSinceReferenceDate()
        var elapsedTime = currentTime - startTime
        var seconds = time - elapsedTime

        if seconds > 0 {
            elapsedTime -= NSTimeInterval(seconds)
            timerInProgressCallback(elapsedTime: elapsedTime)
        } else {
            timer.invalidate()
            timerEndedCallback()
        }
    }
}

用法，在您想要使用通用计时器的类中：

MyTimer().startTimer({ () -> Void in
    timerLabel.fadeOut()
}, timerInProgress: { (elapsedTime) -> Void in
    timerLabel.text = "\(Int(elapsedTime))"
})

Answer 2

要在单独的类中使用countdownTimer，请创建一个新类并在MainViewController中实现该类，然后访问这些方法。

或者只是让你的功能全局化。

Answer 3

XCode-＆gt; File-＆gt; New-＆gt; Source-＆gt; Cocoa Touch Class从NSObject扩展

import UIKit
class TimerTest: NSObject {
    var myTimer:NSTimer?
    override init() {
        super.init()
        print("init worked")
        myTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "timerFuncTriggered:", userInfo: nil, repeats: true)
    }
    func timerFuncTriggered(timer:NSTimer) {
        print("timer started")
    }
}

您可以随时使用您的计时器课程：

let myTimer = TimerTest()

Answer 4

tbaranes答案的第4版：

class MyTimer: NSObject {

var startTime: TimeInterval! = TimeInterval()
var time: Double! = 4
var timer: Timer! = Timer()
var timerEndedCallback: (() -> Void)!
var timerInProgressCallback: ((_ elapsedTime: Double) -> Void)!

func startTimer(timerEnded: @escaping () -> Void, timerInProgress: ((_ elapsedTime: Double) -> Void)!) {
    if !timer.isValid {
        let aSelector : Selector = #selector(MyTimer.updateTime)
        timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: aSelector, userInfo: nil, repeats: true)
        startTime = NSDate.timeIntervalSinceReferenceDate
        timerEndedCallback = timerEnded
        timerInProgressCallback = timerInProgress
    }
}

@objc func updateTime() {
    var currentTime = NSDate.timeIntervalSinceReferenceDate
    var elapsedTime = currentTime - startTime
    var seconds = time - elapsedTime

    if seconds > 0 {
        elapsedTime -= TimeInterval(seconds)
        timerInProgressCallback(elapsedTime)
    } else {
        timer.invalidate()
        timerEndedCallback()
    }
}
}

如何在一个单独的类中使用iOS Swift中的计时器？

4 个答案: