[英]How to make a timer in iOS Swift in a separate class?
我已经构建了一个 CountdownTimer,我想将它重构为一个单独的类,以便我可以在 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()
}
}
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()
}
}
}
快速 4 版本的 tbaranes 的回答:
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()
}
}
}
基于@tbaranes 的回答,并且由于编辑队列已满,这是一个可在SWIFT 5<\/strong>上运行的更新版本,并进行了一些调整
protocol CountdownTimerProtocol {
func stopCountdown()
func startCountdown(totalTime: Int, timerEnded: @escaping () -> Void, timerInProgress: @escaping (Int) -> Void)
}
class CountdownTimer: NSObject, CountdownTimerProtocol {
private var timer: Timer?
private var timeRemaining = 0
var timerEndedCallback: (() -> Void)?
var timerInProgressCallback: ((Int) -> Void)?
deinit {
stopCountdown()
}
func stopCountdown() {
timer?.invalidate()
}
func startCountdown(totalTime: Int, timerEnded: @escaping () -> Void, timerInProgress: @escaping (Int) -> Void) {
timeRemaining = totalTime
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(step), userInfo: nil, repeats: true)
timerEndedCallback = timerEnded
timerInProgressCallback = timerInProgress
}
@objc func step() {
if timeRemaining > 0 {
timeRemaining -= 1
timerInProgressCallback?(timeRemaining)
} else {
stopCountdown()
timerEndedCallback?()
}
}
}
要在单独的类中使用您的 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,只需将您的功能设为全局即可。
XCode->File->New->Source->Cocoa Touch Class 扩展自 NSObject<\/em>
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")
}
}
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