DispatchQueue.main.asyncAfter不正确

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问题描述

我试图在延迟后调用一个函数。在iOS10上，我可以使用Timer.scheduledTimer，它确实会在给定的延迟后调用我的关闭。但是，在iOS9上，我正在使用DispatchQueue.main.asyncAfter，它以六秒钟的延迟调用我的闭包。

I am trying to call a function after a delay. On iOS10 I am able to use Timer.scheduledTimer which does indeed call my closure after the given delay. However, on iOS9 I am using DispatchQueue.main.asyncAfter and it calls my closure with a six second delay.

我正在测试的延迟是60秒。 Timer.scheduledTimer在60秒后调用闭包，在66秒后调用DispatchQueue.main.asyncAfter。因此需要六秒钟的延迟，如果我安排两个60秒的延迟，则在132秒之后使用DispatchQueue.main.asyncAfter调用第二个延迟。

The delay I am testing with is 60 seconds. Timer.scheduledTimer calls closure after 60 seconds, DispatchQueue.main.asyncAfter after 66 seconds. The six second delay is consequent, if I schedule two delays of 60 seconds the second delay is called after 132 seconds using DispatchQueue.main.asyncAfter.

func delay(delay:Double, closure:@escaping ()->()) {
    NSLog("Calling method with delay of: \(delay)")

    if #available(iOS 10.0, *) {
        Timer.scheduledTimer(withTimeInterval: delay, repeats: false) { (timer) in
            closure()
        }
    } else {
        // TODO: Is not accurate, delay of +- 6 seconds
        DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
            closure()
        }
    }
}

调用延迟函数的代码：

func scheduleStudy(minutes: Int, secondsFromNow: Int) {
    // Study notification
    if #available(iOS 10.0, *) {
        self.addiOS10StudyNotification(minutes: minutes, secondsFromNow: secondsFromNow)
    }else{
        self.addiOS9StudyNotification(minutes: minutes, secondsFromNow: secondsFromNow)
    }

    // Study timer
    delay(delay: Double(secondsFromNow)) {
        self.onStudy(minutes: minutes)
    }

    NSLog("Scheduled study for \(minutes) minutes in \(secondsFromNow) seconds from now.")
}

使用Timer.scheduledTimer计划通知和方法调用

Planning notifications and methods calls using Timer.scheduledTimer

2016-12-06 13:34:06.024714 Mattie[1386:360881] Calling method with delay of: 0.0
2016-12-06 13:34:06.025072 Mattie[1386:360881] Scheduled study for 1 minutes in 0 seconds from now.
2016-12-06 13:34:06.036953 Mattie[1386:360881] Calling method with delay of: 60.0
2016-12-06 13:34:06.037191 Mattie[1386:360881] Scheduled pause for 1 minutes in 60 seconds from now.
2016-12-06 13:34:06.052520 Mattie[1386:360881] Calling method with delay of: 120.0
2016-12-06 13:34:06.053162 Mattie[1386:360881] Scheduled study for 1 minutes in 120 seconds from now.
2016-12-06 13:34:06.066838 Mattie[1386:360881] Calling method with delay of: 180.0
2016-12-06 13:34:06.067027 Mattie[1386:360881] Scheduled finish in 180 seconds from now.

暂停被称为：

2016-12-06 13:35:06.038307 Mattie[1386:360881] ON PAUSE
2016-12-06 13:35:06.065389 Mattie[1386:360881] Added pause timer for 1 minutes

计划在13:34:06，在13:35:06调用

Planned in at 13:34:06, called at 13:35:06

使用DispatchQueue.main.asyncAfter

Planning notifications and methods calls using DispatchQueue.main.asyncAfter

2016-12-06 13:36:48.845838 Mattie[1390:361681] Calling method with delay of: 0.0
2016-12-06 13:36:48.847389 Mattie[1390:361681] Scheduled study for 1 minutes in 0 seconds from now.
2016-12-06 13:36:48.854336 Mattie[1390:361681] Calling method with delay of: 60.0
2016-12-06 13:36:48.854543 Mattie[1390:361681] Scheduled pause for 1 minutes in 60 seconds from now.
2016-12-06 13:36:48.861424 Mattie[1390:361681] Calling method with delay of: 120.0
2016-12-06 13:36:48.861601 Mattie[1390:361681] Scheduled study for 1 minutes in 120 seconds from now.
2016-12-06 13:36:48.868464 Mattie[1390:361681] Calling method with delay of: 180.0
2016-12-06 13:36:48.868644 Mattie[1390:361681] Scheduled finish in 180 seconds from now.

暂停被称为：

2016-12-06 13:37:54.865400 Mattie[1390:361681] ON PAUSE
2016-12-06 13:37:54.897354 Mattie[1390:361681] Added pause timer for 1 minutes

计划在13:36:48，在13:37:54调用

Planned in at 13:36:48, called at 13:37:54

asyncAfter

DispatchQueue.main.asyncAfter不正确

问题描述

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