Implementing NSTimer into Code - Swift

Question

I am having a bit of trouble using / implementing NSTimer into code. So far, i have this:

//Delay function from http://stackoverflow.com/questions/24034544/dispatch-after-gcd-in-swift/24318861#24318861
func delay(delay:Double, closure:()->()) {
    dispatch_after(
        //adds block for execution at a specific time
        dispatch_time(
            //creates a dispatch time relative to default clock
            DISPATCH_TIME_NOW,
            //Indicates that something needs to happen imediately
            Int64(delay * Double(NSEC_PER_SEC))
            //a 64bit decleration that holds the delay time times by the amount of nanoseconds in one seconds, inorder to turn the 'delay' input into seconds format
        ),
        dispatch_get_main_queue(), closure)
}


@IBAction func computerTurn(){

    if(isFirstLevel){levelLabel.text = ("Level 1"); isFirstLevel = false}
    else{ level++ }

    var gameOrderCopy = gameOrder
    var randomNumber = Int(arc4random_uniform(4))
    gameOrder.append(randomNumber)
    var i = 0
    var delayTime = Double(1)

    println(Double(NSEC_PER_SEC))
    for number in self.gameOrder{


        if number == 0{
            delay(delayTime++){self.greenButton.highlighted = true}
            self.delay(delayTime++){
                self.greenButton.highlighted = false
            }
        }

        else if number == 1{
            delay(delayTime++){self.redButton.highlighted = true}
             self.delay(delayTime++){
                self.redButton.highlighted = false
            }

        }

        else if number == 2{
            delay(delayTime++){self.yellowButton.highlighted = true}
             self.delay(delayTime++){
                self.yellowButton.highlighted = false
            }
        }
        else if number == 3{
            delay(delayTime++){self.blueButton.highlighted = true}
             self.delay(delayTime++){
                self.blueButton.highlighted = false
            }
        }
        println(delayTime)


    }
}

What i need to do, is replace the timer function, or get rid of it, and do the same as whats happening here, but using NSTimer.

Thanks

Answer 1

NSTimer can be a little clunky in this context because it requires using either target-action or NSInvocation. However, NSTimer is toll-free bridged with CFRunLoopTimer, which you can call with a block:

func delay(delay:Double, closure:()->()) {
    let fireDate = delay + CFAbsoluteTimeGetCurrent()
    let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, fireDate, 0, 0, 0) { _ in
        closure()
    }
    CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, kCFRunLoopCommonModes)
}