LazyVStack issue

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Created Feb ’24

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Hello everyone, first post here! It seems I have a problem with LazyVStack, either because of a bug or because I have not yet understood how to use them properly. This simple piece of code, with the messagesString being a simple array of strings, causes the scrollview to lag when scrolling.

        ScrollView{
            LazyVStack {
                ForEach(0..<messagesString.count - 1 , id: \.self){index in
                    Text("\(messagesStringAO[index])")
                        .id(index)
                }
            }
            
        }
    }

Using a simple Vstack fixes the lag issue. It seems to me that associating the string in the array to the content of the view causes the problem. Any help would be greatly appreciated! Thanks :)

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Answer 1

SimoneDeAngelis OP

Feb ’24

Ok It seems that the issue is caused by items that have a dynamic height ( such as texts in a chat). I've found an already existing post reporting this same issue [https://stackoverflow.com/questions/68459594/content-with-variable-height-in-a-lazyvstack-inside-a-scrollview-causes-stutteri], and even though it's been reported 2 years ago, it seems that the issue is still there ( I'm running the code on a Iphone 13 pro with iOS 17.2.1). The author of the post I linked said that he got a reply from Apple confiriming it's a bug of swiftUI, so I guess the only way to implement a scrollable component with lazy behaviour is customizing a VStack inside a scroll view and implement lazy loading by ourselves. If anyone has ever found a workaround for this issue I would really appreciate it! Thank you for reading! :)

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