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?

Solution 1

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);
    }
}

Solution 2

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

Solution 3

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

Solution 4

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);
    }
}

Solution 5

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

View more solutions

Comments

[Jon]

If using a UIPanGestureRecognizer, the built in method - (CGPoint)translationInView:(UIView *)view works very well.

[Fattie]

You'd certainly use translationInView here. Perhaps MB could edit the answer one day, since, it's such a high-marker! Eg stackoverflow.com/questions/15888276/… Rock on...

[Apollo]

@MatthiasBauch is this in inches?

[GhostCat]

Please note: code only answers are discouraged. Please add a bit of explanation.

[Radu Ursache]

for lazy people you should also declare var startLocation = CGPoint() in your class

[Hari Kunwar]

Its the equation to calculate distance between two points. mathsisfun.com/algebra/distance-2-points.html

[Mark Perkins]

agreed @RaduUrsache, there is no way to store the start location in this solution above.