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?
You can swipe left or right from the Apps screen of your Android phone or tablet to see more pages of apps. When you're using a web browser or an app such as Facebook or WhatsApp, you can swipe up to move down the page, and swipe back down to return to where you started.
Overview. UISwipeGestureRecognizer is a concrete subclass of UIGestureRecognizer . UISwipeGestureRecognizer recognizes a swipe when the user moves the specified number of touches ( numberOfTouchesRequired ) in an allowable direction ( direction ) far enough to create a swipe.
A swipe gesture recognizer detects swipes in one of four directions, up , down , left , and right . We set the direction property of the swipe gesture recognizer to down . If the user swipes from the top of the blue view to the bottom of the blue view, the swipe gesture recognizer invokes the didSwipe(_:)
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);
}
}
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
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