SwiftUI Gestures prevent scrolling with iOS 18

Question

shiftingsand OP

Created Jul ’24

Replies 9

Boosts 13

Views 1.6k

Participants 9

I added gesture support to my app that supports iOS 16 and 17 and have never had issues with it.

However, when I compiled my app with Xcode 16 I immediately noticed a problem with the app when I ran it in the simulator. I couldn't scroll up or down. I figured out it’s because of my gesture support.

My gesture support is pretty simple.

        let myDragGesture = DragGesture()
            .onChanged { gesture in
                self.offset = gesture.translation
            }
            .onEnded { _ in
                    if self.offset.width > threshold {
                       ...some logic
                    } else if self.offset.width < -threshold {
                       ...some other logic
                    }
                              
                logitUI.debug("drag gesture width was \(self.offset.width)")
                self.offset = .zero
            }

If I pass nil to .gesture instead of myDragGesture then scrolling starts working again.

Here’s some example output when I’m trying to scroll down. These messages do NOT appear when I run my app on an iOS 16/17 simulator with Xcode 15.

drag gesture width was 5.333328
drag gesture width was -15.333344
drag gesture width was -3.000000
drag gesture width was -24.333328
drag gesture width was -30.666656

I opened FB14205678 about this.

Boost

Answer 1

DTS Engineer OP

Apple

Jul ’24

Thanks for flagging this @shiftingsand. Your bug report is being investigated, please continue to test on the latest beta and verify if you still see the same behavior or not and include your results as part of your bug report.

1

Answer 2

shiftingsand OP

Aug ’24

No change with Version 16.0 beta 5 (16A5221g).

0

Answer 3

shiftingsand OP

Aug ’24

No change with Version 16.0 beta 6 (16A5230g).

1

Answer 4

Audentia OP

3w

I also have this issue, no change in Xcode 16 RC and iOS 18 RC. this is very disappointing and will break a lot of apps. What's up apple? Or am I missing something how to fix this?

I have a horizontal scroll view and each view has a drag gesture which on vertical drag would dismiss the view. This worked in iOS 17.5 and Xcode 15.4 but not on the latest as I mention above.

My fix is to use .simultaneousGesture rather than just .gesture modifier block, it seems to work and the view is more dynamic as the horizontal scroll and individual view's drag gestures work together simultaneously rather than one or the other. Is this the intended behavior Apple wants? That's fine, but more explanation and documentation would really go a long way to help here.

2

Answer 5

nszombie OP

3w

Suffering the same, all our app is broken, and using .simultaneousGesture unlocks a dance of gestures.

1

Answer 6

AaronXu OP

2w

Same problem in my app. I develop a comic read app, use UIPageViewController as basic reader. And I add a clear layer with tap gesture, when user tap center area, will open a control panel to adjust reading preference. But now I can't scroll UIPageViewController by swipe gesture.

here is a simple version of my code:

struct TestFunctionView: View {
    var body: some View {
        ZStack {
            TabView {
                Text("1")
                Text("2")
            }
            .tabViewStyle(.page)
            
            Rectangle()
                .foregroundColor(.clear)
                .contentShape(Rectangle())
                .onTapGesture(count: 1){
                    print("Tap")
                }
        }
    }
}

In iOS 17, both tap and scroll gesture can be trigger. but in iOS 18, it's not.

Really help apple can fix it, or it there another way to code my requirement?

0

Answer 7

Veljko OP

2w

C'mon Apple really?!

I have Images array with option to swipe horizontally and tap gesture to open image sometimes works some times it doesn't.

I found a solution:

.highPriorityGesture(
        TapGesture()
            .onEnded {
                // Tap logic
            }
    )

The real problem is that I need to check every tap gesture in my app because some works some doesn't... fix this quick!

1

Answer 8

wmk OP

1w

iOS 18.0 (public)

Same here; all ScrollViews containing elements with DragGesture() don't scroll properly and this is causing major headaches. I've switched some from .highPriorityGesture() to .simultaneousGesture() as a stopgap measure.

7

Answer 9

Mushruum OP

4d

To provide more information, it seems that .gesture() is not recognized on the current view but on the previous view in the navigation stack on an iOS 18 device.

I happened to support two different customized zoom gestures in my two views in the navigation stack, both are implemented based on .MagnifyGesture().

When I zoom on the second page, nothing happens; but when I navigated back to the previous page, I saw the zoom gesture had been triggered.

0