CODEWITHSUNDEEP
iosswiftuicollectionviewuikitswipe
Andrii Solokh
Andrii Solokh

Reputation: 54

Swipe from the edge of screen, over UICollectionView

Scheme of views

Greetings to everyone!

I have :

What is problem?

I can`t catch touch, swipe events in parent view controller.

What do I mean?

When I try to catch touch event using :

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {...

in A View controller I can see such results.

I try to catch swipes by UIScreenEdgePanGestureRecognizer added to A_view

Touch on A View -> touchesBegan(...) -> works

Swipe on A View -> UIScreenEdgePanGestureRecognizer -> works

Touch on B View -> touchesBegan(...) -> works

Swipe on B View -> UIScreenEdgePanGestureRecognizer -> works

Touch on C View -> touchesBegan(...) -> doesn't work

Swipe on C View -> UIScreenEdgePanGestureRecognizer -> doesn't work

I noticed that I can catch touch events in C view controller.

Question

Is there possibility to catch swipe/touch events produced on C view ( UICollectionView) in A view controller (UIViewController).

My Goal

My goal is to make SideBar view, and when I try to catch swipe on the edge of screen over C view (UICollectionView) it just scrolling inside, but I want to open SideBar when finger start

Upvotes: 1

Views: 1446

Answers (3)

Woody Jean-louis
Woody Jean-louis

Reputation: 535

If you need the edge swipe gesture to be recognized over every scrollView. (UICollectionView is a UIScrollView)

extension UIScrollView {
    open override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        print("gesture recognizer should begin")
        print(gestureRecognizer)
        let app = UIApplication.shared.delegate as? AppDelegate
        if let view = app?.window?.rootViewController?.view, !(gestureRecognizer is UIScreenEdgePanGestureRecognizer) {
            let location = gestureRecognizer.location(in: view)
            if location.x < view.frame.maxX * 0.05 || location.x > view.frame.maxX * 0.95 {
                return false
            }
        }
        return super.gestureRecognizerShouldBegin(gestureRecognizer)
    }
}

Upvotes: 1

Andrii Solokh
Andrii Solokh

Reputation: 54

  1. I have added UIGestureRecognizerDelegate to parent classes of A View viewController.

    class A_viewController: UIViewController,UIGestureRecognizerDelegate{...

  2. I have added UIScreenEdgePanGestureRecognizer to A view - parent view.

    let rec = UIScreenEdgePanGestureRecognizer(target: self, action: #selector(handlePanGestRecognizer))
rec.edges = .left
rec.delegate = self
A_view.addGestureRecognizer(rec)

  3. Using method gestureRecognizerShouldBegin(...) catch edge swipes, and calling handlePanGestRecognizer(...) method to produce action. If gestureRecognizer is UIScreenEdgePanGestureRecognizer than do action.

    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool
{
     if gestureRecognizer is UIScreenEdgePanGestureRecognizer
     {
         handlePanGestRecognizer(recognizer: gestureRecognizer as! UIScreenEdgePanGestureRecognizer)
     }
     return false
}

  4. Beside that recognizer.state.rawvalue = 0, so recognizer.state is not .begun when handlePanGestRecognizer() method fired.

    func handlePanGestRecognizer(recognizer : UIScreenEdgePanGestureRecognizer){...

Upvotes: 0

ystack
ystack

Reputation: 1805

Override the function: optional func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool in the parent A View & return appropriate BOOLs.
Keep in mind that for a view whose userInteractionEnabled attribute is set to true, any touches/gestures in that view won't be propagated to the parent view (unless shouldReceive touch is overrided to say otherwise)

Upvotes: 0

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