swift - 继续之前的倒计时 - swift

Question

需要帮助制作一个倒计时器，直到其失效才能继续。它也不应该阻塞主线程。有什么建议吗？

private var currentCountdownSeconds = 3
private var countdownTimer = Timer()

private func performTimer() {

    if secondsToCountDown != 0 {
        print(secondsToCountDown)
        countdownTimer = Timer(timeInterval: 1, target: self, selector: #selector(handleCountdown), userInfo: nil, repeats: true)
    }

}

@objc private func handleCountdown() {
    previewView.countdownLabel.text = "\(currentCountdownSeconds)"
    currentCountdownSeconds -= 1
    print(secondsToCountDown)
    if secondsToCountDown == 0 {
        countdownTimer.invalidate()
    }
}

public func toggleMovieRecording() {
    handleTimer()
    videoCaptureLogic()
}

public func toggleCapturePhoto() {
    handleTimer()
    videoCaptureLogic()
}

Answer 1

如果您必须在多个地方使用倒计时，请尝试这个。

private var currentCountdownSeconds = 3
private var countdownTimer = Timer()

private func performTimer() {

    if secondsToCountDown != 0 {
        print(secondsToCountDown)
        countdownTimer = Timer(timeInterval: 1, target: self, selector: #selector(handleCountdown), userInfo: nil, repeats: true)
    }

}

@objc private func handleCountdown() {
    previewView.countdownLabel.text = "\(currentCountdownSeconds)"
    currentCountdownSeconds -= 1
    print(secondsToCountDown)
    if secondsToCountDown == 0 {
        countdownTimer.invalidate()
        NotificationCenter.default.post(notification: NSNotification.Name.init("TimeComplete")
    }
}

现在，在您需要的任何类中实现通知的观察者。当倒计时完成并发布通知时，相应的选择器将处理该事件。

class Something {

    init() {
        NotificationCenter.default.addObserver(self, selector: #selector(timerCompleteAction), name: NSNotification.Name.init("TimerComplete"), object: nil)
    }

    @objc func timerCompleteAction() {
          //Do necessary actions
    }
}

Something 可以是具有视频捕获功能的类，在这种情况下，将该代码写入 timerCompleteAction 中。然后再次在进行音频捕获的类中，添加相同的观察者并添加选择器方法并执行音频捕获操作。