你需要在Swift 3中使用Timer而不是NSTimer。

这里有一个例子:

Timer.scheduledTimer(timeInterval: 1, 
    target: self, 
    selector: #selector(YourController.update), 
    userInfo: nil, 
    repeats: true)

// @objc selector expected for Timer
@objc func update() {
    // do what should happen when timer triggers an event
}

检查:

斯威夫特2

var timer = NSTimer.scheduledTimerWithTimeInterval(0.01, target: self, selector: Selector("update"), userInfo: nil, repeats: true)

斯威夫特，3,4,5

var timer = Timer.scheduledTimer(timeInterval: 0.01, target: self, selector: #selector(self.update), userInfo: nil, repeats: true)

首先声明你的计时器

var timer: Timer?

然后在viewDidLoad()或任何你想要启动计时器的函数中添加line

timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(action), userInfo: nil, repeats: false)

这是func，你将回调它来做一些事情它必须是@objc

@objc func action () {
print("done")
}

更新到Swift 4，利用userInfo:

class TimerSample {

    var timer: Timer?

    func startTimer() {
        timer = Timer.scheduledTimer(timeInterval: 5.0,
                                     target: self,
                                     selector: #selector(eventWith(timer:)),
                                     userInfo: [ "foo" : "bar" ],
                                     repeats: true)
    }

    // Timer expects @objc selector
    @objc func eventWith(timer: Timer!) {
        let info = timer.userInfo as Any
        print(info)
    }

}

在Swift 3中使用@objc:

func startTimerForResendingCode() {
    let timerIntervalForResendingCode = TimeInterval(60)
    Timer.scheduledTimer(timeInterval: timerIntervalForResendingCode,
                         target: self,
                         selector: #selector(timerEndedUp),
                         userInfo: nil,
                         repeats: false)
}




@objc func timerEndedUp() {
    output?.timerHasFinishedAndCodeMayBeResended()
}

如果你init定时器的方法

let timer = Timer(timeInterval: 3, target: self, selector: #selector(update(_:)), userInfo: [key : value], repeats: false)

func update(_ timer : Timer) {

}

然后将它添加到循环中，使用方法other selector将不会被调用

RunLoop.main.add(timer!, forMode: .defaultRunLoopMode)

注意:如果你想要这个重复，使重复为真，并保持定时器的引用，否则更新方法将不会被调用。

如果你使用这种方法。

Timer.scheduledTimer(timeInterval: seconds, target: self, selector: #selector(update(_:)), userInfo: nil, repeats: true)

如果repeat为真，则保留一个参考供以后使用。