Expandable View

ExpandableView.swift

struct ContentView: View {
    
    @State var isExpanded = false
    @State var subviewHeight : CGFloat = 0
    
    var body: some View {
        VStack {
            Text("Headline")
            VStack {
                Text("More Info")
                Text("And more")
                Text("And more")
                Text("And more")
                Text("And more")
                Text("And more")
            }
        }
        .background(GeometryReader {
            Color.clear.preference(key: ViewHeightKey.self,
                                   value: $0.frame(in: .local).size.height)
        })
        .onPreferenceChange(ViewHeightKey.self) { subviewHeight = $0 }
        .frame(height: isExpanded ? subviewHeight : 50, alignment: .top)
        .padding()
        .clipped()
        .frame(maxWidth: .infinity)
        .transition(.move(edge: .bottom))
        .background(Color.gray.cornerRadius(10.0))
        .onTapGesture {
            withAnimation(.easeIn(duration: 2.0)) {
                isExpanded.toggle()
            }
        }
    }
}

struct ViewHeightKey: PreferenceKey {
    static var defaultValue: CGFloat { 0 }
    static func reduce(value: inout Value, nextValue: () -> Value) {
        value = value + nextValue()
    }
}