Is there a way to get the height of the ScrollView that contains the content in SwiftUI?

Question

I want to calculate how much I can scroll from the height of the entire ScrollView to the bottom of the ScrollView, but I can't get the height of the entire ScrollView. If there is any way to do this, please let me know.

scrollView.contentSize.height scrollView.frame.height

The top two are the values you want to get

var body: some View {
    ScrollView {
        ForEach(0..<100, id: \.self) { number in
            Text("\(number)")
        }
    }
}

The height of ScrollView itself or the height of a ScrollView's content? — Asperi, Jun 02 '20 at 07:39
scrollView.contentSize.height scrollView.frame.height The top two are the values you want to get — zlatan, Jun 02 '20 at 08:00

Asperi · Answer 1 · 2020-06-02T08:18:31.837

0

Here is a solution based on ViewHeightKey preference key from my answer in How to make a SwiftUI List scroll automatically?

var body: some View {
    ScrollView {
        VStack {
            ForEach(0..<100, id: \.self) { number in
                Text("\(number)")
            }
        }
        .modifier(ViewHeightKey())   // calculate here !!
    }
    .onPreferenceChange(ViewHeightKey.self) { // read here !!
        print("Content height: \($0)")
    }
    .background(GeometryReader { gp -> Color in
        let frame = gp.frame(in: .local)
        print("ScrollView height: \(frame.size.height)")
        return Color.clear
    })
}

edited Jun 02 '20 at 08:18

answered Jun 02 '20 at 08:05

Asperi

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I got an error on geometryRender of backgroundmodifier. – zlatan Jun 02 '20 at 08:18
error Explicitly specify the generic arguments to fix this issue – zlatan Jun 02 '20 at 08:18
One more thing, I'm getting an error in the reduce of ViewHeightKey error Reference to invalid associated type 'Value' of type 'ViewHeightKey' – zlatan Jun 02 '20 at 08:33
@zlatan, provided code snapshot tested & works with Xcode 11.4 / iOS 13.4. I suppose the origin of error in your adapting code. – Asperi Jun 02 '20 at 08:47
Is there a way to get the contentOffset.y? – zlatan Jun 03 '20 at 09:34

Is there a way to get the height of the ScrollView that contains the content in SwiftUI?

1 Answers1