UISwipeGestureRecognizer Swipe length

Question

Any idea if there is a way to get the length of a swipe gesture or the touches so that i can calculate the distance?

I think you can only get direction from UISwipeGestureRecognizer. Maybe you can get the position where the touch begin and where it ends and calculate the lengh from that. — picknick, Jan 28 '11 at 14:17

score 58 · Accepted Answer · answered Jan 28 '11 at 14:32

It's impossible to get a distance from a swipe gesture, because the SwipeGesture triggers the method where you could access the location exactly one time, when the gesture has ended.
Maybe you want to use a UIPanGestureRecognizer.

If it possible for you to use pan gesture you would save the starting point of the pan, and if the pan has ended calculate the distance.

- (void)panGesture:(UIPanGestureRecognizer *)sender {
    if (sender.state == UIGestureRecognizerStateBegan) {
        startLocation = [sender locationInView:self.view];
    }
    else if (sender.state == UIGestureRecognizerStateEnded) {
        CGPoint stopLocation = [sender locationInView:self.view];
        CGFloat dx = stopLocation.x - startLocation.x;
        CGFloat dy = stopLocation.y - startLocation.y;
        CGFloat distance = sqrt(dx*dx + dy*dy );
        NSLog(@"Distance: %f", distance);
    }
}

If using a UIPanGestureRecognizer, the built in method - (CGPoint)translationInView:(UIView *)view works very well. — Jon, Aug 06 '13 at 18:30
You'd certainly use translationInView here. Perhaps MB could edit the answer one day, since, it's such a high-marker! Eg http://stackoverflow.com/questions/15888276/with-uipangesturerecognizer-is-there-a-way-to-only-act-so-often-like-after-x-m Rock on... — Fattie, Feb 22 '14 at 10:15

score 16 · Answer 2 · edited May 07 '19 at 02:05

In Swift

 override func viewDidLoad() {
    super.viewDidLoad()

    // add your pan recognizer to your desired view
    let panRecognizer = UIPanGestureRecognizer(target: self, action:  #selector(panedView))
    self.view.addGestureRecognizer(panRecognizer)

}

   @objc func panedView(sender:UIPanGestureRecognizer){
        var startLocation = CGPoint()
        //UIGestureRecognizerState has been renamed to UIGestureRecognizer.State in Swift 4
        if (sender.state == UIGestureRecognizer.State.began) {
            startLocation = sender.location(in: self.view)
        }
        else if (sender.state == UIGestureRecognizer.State.ended) {
            let stopLocation = sender.location(in: self.view)
            let dx = stopLocation.x - startLocation.x;
            let dy = stopLocation.y - startLocation.y;
            let distance = sqrt(dx*dx + dy*dy );
            NSLog("Distance: %f", distance);

        if distance > 400 {
            //do what you want to do
        }
    }
}

Hope that helps all you Swift pioneers

for lazy people you should also declare `var startLocation = CGPoint()` in your class — Radu Ursache, Apr 12 '18 at 12:06
agreed @RaduUrsache, there is no way to store the start location in this solution above. — Mark Perkins, Jan 24 '20 at 20:19

score 4 · Answer 3 · edited Aug 26 '17 at 09:02

4

func swipeAction(gesture: UIPanGestureRecognizer) {
    let transition = sqrt(pow(gesture.translation(in: view).x, 2)
                     + pow(gesture.translation(in: view).y, 2))
}

edited Aug 26 '17 at 09:02

Massimiliano Kraus

3,638
5
27
47

answered Aug 25 '17 at 11:08

Møhãməđ Đąŕwîčh

41
3

4

Please note: code only answers are discouraged. Please add a bit of explanation. – GhostCat Aug 25 '17 at 11:31
Its the equation to calculate distance between two points. https://www.mathsisfun.com/algebra/distance-2-points.html – Hari Kunwar Dec 12 '18 at 21:04

score 3 · Answer 4 · answered Apr 29 '14 at 21:55

For those of us using Xamarin:

void panGesture(UIPanGestureRecognizer gestureRecognizer) {
    if (gestureRecognizer.State == UIGestureRecognizerState.Began) {
        startLocation = gestureRecognizer.TranslationInView (view)
    } else if (gestureRecognizer.State == UIGestureRecognizerState.Ended) {
        PointF stopLocation = gestureRecognizer.TranslationInView (view);
        float dX = stopLocation.X - startLocation.X;
        float dY = stopLocation.Y - startLocation.Y;
        float distance = Math.Sqrt(dX * dX + dY * dY);
        System.Console.WriteLine("Distance: {0}", distance);
    }
}

score 2 · Answer 5 · answered Jan 28 '11 at 14:28

2

You can only do it a standard way: remember the touch point of touchBegin and compare the point from touchEnd.

answered Jan 28 '11 at 14:28

Oleg Danu

4,149
4
29
47

score 0 · Answer 6 · answered Feb 05 '19 at 20:09

I have an implementation similar to the answer in swift that discriminates between a drag and a swipe calculating the distance relative to the container and the speed of the swipe.

@objc private func handleSwipe(sender: UIPanGestureRecognizer) {
    if (sender.state == .began) {
        self.swipeStart.location = sender.location(in: self)
        self.swipeStart.time = Date()
    }
    else if (sender.state == .ended) {
        let swipeStopLocation : CGPoint = sender.location(in: self)
        let dx : CGFloat = swipeStopLocation.x - swipeStart.location.x
        let dy : CGFloat = swipeStopLocation.y - swipeStart.location.y
        let distance : CGFloat = sqrt(dx*dx + dy*dy );
        let speed : CGFloat = distance / CGFloat(Date().timeIntervalSince(self.swipeStart.time))
        let portraitWidth = min(self.frame.size.width, self.frame.size.height)
        print("Distance: \(distance), speed: \(speed), dy: \(dy), dx: \(dx), portraitWidth: \(portraitWidth), c1: \(distance >  portraitWidth * 0.4), c2: \(abs(dy) < abs(dx) * 0.25), c3: \(speed > portraitWidth * 3.0) ")
        if distance >  portraitWidth * 0.4 && abs(dy) < abs(dx) * 0.25 && speed > portraitWidth * 3.0 {
            if dx > 0 {
                delegate?.previousAssetPressed(self)
            }else{
                delegate?.nextAssetPressed(self)
            }
        }
    }
}

UISwipeGestureRecognizer Swipe length

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