Trouble with NSTimer in Swift

Question

I tried this but nothing happened. Is there something wrong with the selector?

    func timer() {
       var timer = NSTimer(timeInterval: 2.0, target: self, selector:Selector("function"), userInfo: nil, repeats: false)
    }
    func function() {
       println("it worked")
    }

See here: http://stackoverflow.com/questions/24007650/selector-in-swift. The selector thing is not really a thing in Swift. — CannibalGorilla, Jun 18 '14 at 19:51

score 12 · Accepted Answer · answered Jun 18 '14 at 19:49

12

You're just creating the timer, but not adding it to the run loop. You'll either need to use the equivalent scheduledTimerWithTimeInterval:target:selector:userInfo:repeats: class method or schedule it on the run loop with addTimer:forMode:.

answered Jun 18 '14 at 19:49

Chuck

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It tried using the first option you stated and it didn't fire either. – bhzag Jun 18 '14 at 20:02
@user: Is this in an environment where a run loop is running? – Chuck Jun 18 '14 at 20:05
How do I tell if a run loop is running? – bhzag Jun 18 '14 at 20:13
1

@user3746375: If it's a normal AppKit or UIKit app with a functioning interface that doesn't have any alerts or menus open, it probably has a running run loop. If that isn't the case and you don't know if you have one, you probably don't. – Chuck Jun 18 '14 at 20:17
To add a timer to a run loop: Swift 3: `RunLoop.current.add(myTimer, forMode: RunLoopMode.commonModes)` – twodayslate Mar 06 '17 at 17:57

score 4 · Answer 2 · edited Jul 26 '19 at 00:40

You can use this code for your NSTimer:

Swift 2

func timer() {
   var timer = NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: "timerFunc", userInfo: nil, repeats: false)
}
func timerFunc() {
   println("it worked")
}

Swift 3, 4, 5

func timer() {
    var timer = Timer.scheduledTimer(timeInterval: 2.0, target: self, selector: #selector(timerFunc), userInfo: nil, repeats: false)
}
@objc func timerFunc() {
    print("it worked")
}

You have to use the scheduledTimerWithTimeInterval:target:selector:userInfo:repeats: class method to run your timer.

Hope this can help you.

score 0 · Answer 3 · answered Jul 11 '14 at 19:28

you create the Selector like below.

let @Selector : Selector = "timerFireMethod:"

and then create the timer

var timer = NSTimer.scheduledTimerWithTimeInterval(1.0, 
                target: self, 
                selector: @Selector,
                userInfo: userInfo, 
                repeats: true)

Trouble with NSTimer in Swift

3 Answers3