Custom modifier block the ScrollView scroll action

Question

I have a Scrollview (pretty basic)

        ScrollView(.vertical, showsIndicators: false, content: {
            VStack(content: {
                ForEach(self.elements, id: \.self) { _ in
                    Rectangle()
                        .frame(height: 30)
                        .background(Color.green)
                }
            })
        })
        .bottomInnerShadow(color: Color.black.opacity(0.45), radius: 0.5)

And I am using a custom Specifier define as followed

fileprivate extension View {
    func bottomInnerShadow(color: Color, radius: CGFloat = 0.1) -> some View {
        modifier(BottomInnerShadow(color: color, radius: min(max(0, radius), 1)))
    }
}

private struct BottomInnerShadow: ViewModifier {
    var color: Color = .gray
    var radius: CGFloat = 0.1

    private var colors: [Color] {
        [color.opacity(0.49), color.opacity(0.0), .clear]
    }

    func body(content: Content) -> some View {
        GeometryReader { geo in
            content
                .overlay(LinearGradient(gradient: Gradient(colors: self.colors), startPoint: .bottom, endPoint: .top)
                            .frame(height: self.radius * self.minSide(geo)),
                         alignment: .bottom)
        }
    }

    func minSide(_ geo: GeometryProxy) -> CGFloat {
        CGFloat(3) * min(geo.size.width, geo.size.height) / 2
    }
}

It allows me to create a shadow. The issue here is that it is blocking my scrollview actions. I can't scroll anymore where the shadow appear. I tried allowsHitTesting(false) && .disabled(true) but it doesn't work.

Do you guys have an idea how I could overpass that?

Thank you in advance for any future help :D

PS: I already checked that link -> How to disable user interaction on SwiftUI view? and also a link on the apple forum (don't have it here).

Amir Pirzad · Accepted Answer · 2020-09-25 09:14:20Z

0

Just change ViewModifier to

private struct BottomInnerShadow: ViewModifier {
    var color: Color = .gray
    var radius: CGFloat = 0.1

    private var colors: [Color] {
        [color.opacity(0.49), color.opacity(0.0), .clear]
    }

    func body(content: Content) -> some View {
        GeometryReader { geo in
            ZStack {
                Rectangle().fill(Color.clear).overlay(LinearGradient(gradient: Gradient(colors: self.colors), startPoint: .bottom, endPoint: .top)
                                        .frame(height: self.radius * self.minSide(geo)),
                                    alignment: .bottom)
                content
            }

        }
    }

    func minSide(_ geo: GeometryProxy) -> CGFloat {
        CGFloat(3) * min(geo.size.width, geo.size.height) / 2
    }
}

answered Sep 25, 2020 at 9:14

Amir Pirzad

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1 Comment

Oleg G. Over a year ago

This is nice, but I need the shadow on top so it overlays the scrollview. This is under

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