This ScrollView has a modifier called `onScroll`, which is updated when scrolls occur.

A - Usage.swift

struct ContentView: View {

    @State var scrollOffset: CGPoint = .zero

    var body: some View {
        ObservableScrollView {
            Text("Hello, world!")
                .foregroundColor(self.scrollOffset.y == 0 ? .blue : .red)
        }
        .onScroll { self.scrollOffset = $0 }
    }
}

ObservableScrollView.swift

struct ScrollOffsetPreferenceKey: PreferenceKey {
    typealias Value = CGPoint
    static var defaultValue = CGPoint.zero

    static func reduce(value: inout CGPoint, nextValue: () -> CGPoint) {
        value = nextValue()
    }
}

struct ObservableScrollView<Content> : View where Content : View {

    var content: Content

    var axes: Axis.Set

    var showsIndicators: Bool

    init(_ axes: Axis.Set = .vertical, showsIndicators: Bool = true, @ViewBuilder content: () -> Content) {
        self.content = content()
        self.axes = axes
        self.showsIndicators = showsIndicators
    }

    var body: some View {
        GeometryReader { outerGeometry in
            ScrollView(self.axes, showsIndicators: self.showsIndicators) {
                ZStack(alignment: self.axes == .vertical ? .top : .leading) {
                    GeometryReader { innerGeometry in
                        Color.clear
                            .preference(key: ScrollOffsetPreferenceKey.self, value: CGPoint(x: (outerGeometry.frame(in: .global).minX - innerGeometry.frame(in: .global).minX), y: (outerGeometry.frame(in: .global).minY - innerGeometry.frame(in: .global).minY)))
                    }
                    VStack {
                        self.content
                    }
                }
            }
        }
    }
}

extension ObservableScrollView {
    func onScroll(_ onScroll: @escaping (CGPoint) -> ()) -> some View {
        self.onPreferenceChange(ScrollOffsetPreferenceKey.self, perform: onScroll)
    }
}

thank you for sharing, will give it a try 👍

Fixed a bug, with inspiration from https://medium.com/@maxnatchanon/swiftui-how-to-get-content-offset-from-scrollview-5ce1f84603ec who uses a similar technique

Thanks for sharing!!!

I did a quick test but found that any layout change causing the infinite loop. for example, offset ObservableScrollView Y position or image height based on offset. is there a way to fix the call back only for content scroll not the frame change?

struct ContentView: View {
@State var scrollOffset: CGPoint = .zero

var body: some View {
    VStack {
        //1
        Image("logo_stjc")
            .resizable()
            .aspectRatio(contentMode: .fill)
            .clipped()
            .frame(height: 400)
        //2
        VStack {
            Image(systemName: "trash")
                .frame(width: 50.0, height: 50.0)
        }
        .frame(width: 200, height: 100)
        //3
        ObservableScrollView {
            VStack(spacing: 20) {
                HStack(spacing: 20){
                    //some vie
                }
            }
        }.onScroll { self.scrollOffset = $0 }
    }
}

}

@palanishankar07 to be honest, i haven’t been able to get this code to work reliably, so I’ve kind of abandoned it. I’m not getting the body var get called when the user scrolls. Let me know if you have better luck with it!

If anyone has been looking for a solution I found this really convenient to use
It has all kinds of customisation available, like making the scrollview a grid scrollview , tracking scroll offset putting a header, adjusting padding etc
It is a brilliant solution