iOS 13: UIScrollView no longer scrolls

Sorry if I do not catch it.

Could you explain : The idea is that the user can scroll the segmented control back and forth.

What does scrollin a segmented control mean ? Do you mean it gets out of visible part ?

What was the effect (I mean which function called, such as viewDidAppear, …) before IOS13 that produced the desired effect ?

Thanks for the response. The scroll view's content is the control and the width of the control is wider then the device's screen. For instance the control has 8 segments but the screen is only wide enough to display 3 at a time. To see the other segments the user scrolls the view left or right. I can scroll the view progammatically but it doesn't scroll via user touches.

(I included a picture but it doesn't display)

You should detail the exact setup.

Unfortunately, no image possible on the forum.

Is it Swift or SwiftUI ?

have you defined constraints on different views ?

How is the scrollView defined (whole size, content offset …)

I tested some mockup code and seems to work (iOS 13 simulator).

I set the scrollView background to color to see it.

class ViewController: UIViewController {
   
    @IBOutlet weak var scrollView: UIScrollView!
   
    @IBOutlet weak var segmentedControl: UISegmentedControl!
   
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        scrollView.contentSize = CGSize(width: 1000, height: 1000)
        scrollView.contentOffset = CGPoint(x: 50, y: 50 )
    }

    @IBAction func selectSegment(_ sender: UISegmentedControl) {
       
        print(segmentedControl.selectedSegmentIndex)
    }
   
}

Then I can scroll the view and make next segments to appear.

I can select segments from 0 to 7.

Is is important that the scrollView contentSize be larger than the frame, otherwise, no scroll.

It's actually Objective-C - this code's been around for awhile - and as I pointed out this works fine for every version of iOS up to 13. Here's the relevent set-up code:

  NSInteger numSegs=typeControl.numberOfSegments-2;
  CGFloat offset=[self eventTypeScrollViewOffset];
  typeControl.frame=CGRectMake(0, 0, (kEventTypeScrollPadding*2)+(kEventTypeSegmentWidth*numSegs), typeScrollView.frame.size.height);
  typeScrollView.contentInset = UIEdgeInsetsMake(0, -offset, 0, offset);
  typeScrollView.scrollEnabled=YES;
  typeScrollView.contentSize=CGSizeMake(typeControl.frame.size.width-(offset*2),typeScrollView.frame.size.height);

and here's the output from the debugger after the scroll view has been set-up:

<UIScrollView: 0x7f93ba0d2600; frame = (0 0; 375 30); clipsToBounds = YES; autoresize = W+BM; gestureRecognizers = <NSArray: 0x600002f90360>; layer = <CALayer: 0x6000020fb880>; contentOffset: {188, 0}; contentSize: {1125, 30}; adjustedContentInset: {0, -187.5, 0, 187.5}>

As you can see the contentSize is set and larger then the frame.

Here's a link to screenshot that show's the actual implementation: https://i.stack.imgur.com/Fmpou.png

Turns out the issue isn't with the scroll view but with the segmented control. In iOS 13 you can swipe/pan to change the selected segment which prevents the scroll view from scrolling. The solution is to subclass the control, override

class NoSwipeSegmentedControl: UISegmentedControl {
    override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}

Here's a link to the relevant posting on stack overflow: https://stackoverflow.com/questions/58177165/ios-13-segmented-control-remove-swipe-gesture-to-select-segment

Thanks for feedback.

How do you swipe the segmented control ?

I can swipe the scollView, but nothing occurs when I swipe the segmented control.

As mentioned in the stack overflow posting in iOS 13 sliding your finger across a segmented control selects segments. I assume you're running 13 so I'm not sure why you're not seeing it.