swift handling single and double tap

Question

I found some good code on another stack overflow question for this, however my single tap code is running when I do a single tap or a double tap. heres the code (by the way, double tap meaning I tap once, and within 0.3 seconds I tap again, not 2 fingers simultaneously tapping)

    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        let touch: AnyObject? = touches.anyObject()
        if (touch?.tapCount == 2) {
            NSObject.cancelPreviousPerformRequestsWithTarget(self)
        }
    }

    override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
        let touch: AnyObject? = touches.anyObject()
        if (touch?.tapCount == 1) {
            let dispatchTime: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, Int64(0.3 * Double(NSEC_PER_SEC)))
            dispatch_after(dispatchTime, dispatch_get_main_queue(), {
                println("this runs only if single tap")
            })
        } else if (touch?.tapCount == 2) {
            println("double tap touches ended")

        }
    }

I thought that the NSObject.cancelPreviousPerformRequestsWithTarget(self) is supposed to stop the single tap block from running, however my println("this runs only if single tap") is still running when I double tap. First my double tap runs, then after 0.3 seconds the single tap code runs too.. any ideas on what I'm doing wrong?

Did you enable multiple touches on the view? By default, multiple touches are disabled. — Adis, Dec 21 '14 at 19:03
@Adis yea I did, this is actually inside an class that extends an SKSpriteNode — Abdul Ahmad, Dec 21 '14 at 19:05
I think You need to use requiregesturerecognizertofail. This has an Objective C example. http://stackoverflow.com/a/8876299/1203475 — David L, Dec 22 '14 at 05:44
@DavidL I'm not using gestures though, i figured out my problem — Abdul Ahmad, Dec 22 '14 at 12:41

score 0 · Answer 1 · edited May 23 '17 at 12:31

0

the problem was that

NSObject.cancelPreviousPerformRequestsWithTarget(self)

does not cancel a

dispatch_after(dispatchTime, dispatch_get_main_queue()

therefore this will never work. See my other question for further details about this

edited May 23 '17 at 12:31

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answered Dec 22 '14 at 12:45

Abdul Ahmad

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Miguel Gallego · Answer 2 · 2022-09-12T20:51:53.603

I found the same problem. Finally this code works right for me:

var isDoubleTap = false
let timeToWaitAsecondTap: TimeInterval = 0.2  // Whatever you need

func singleTapAction() {
    if isDoubleTap {
        return
    }
    print(#function)
}

func doubleTapAction() {
    print(#function)
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touch = touches.first else {
        return
    }
    if touch.tapCount == 1 {
        DispatchQueue.main.asyncAfter(deadline: .now() + timeToWaitAsecondTap) {
            self.singleTapAction()    // always execute
            self.isDoubleTap = false  // always execute
        }
    } else if touch.tapCount == 2 {
        isDoubleTap = true  // not-always execute
        doubleTapAction()   // not-always execute
    }
}

swift handling single and double tap

2 Answers2