SwiftUI ScrollView only scroll in one direction

As of Xcode 11 beta 3 (11M362v) there is an axes parameter when constructing a ScrollView which can be set to .horizontal or .vertical

ScrollView(.vertical, showsIndicators: true) { ... }

This can be achieved with a GeometryReader. Wrap your ScrollView in one and then set the width of your VStack.

GeometryReader is a super easy, and pretty useful trick to have in your belt for SwiftUI :)

Here's how I got it working with your code:

NavigationView {
            GeometryReader { geometry in
                ScrollView {
                    VStack(alignment: .leading){
                        ForEach(self.friends) { friend in
                            NavigationButton(destination: MessageDetailView(friend: friend)) {
                                CustomListItem(friend: friend)
                    }.frame(width: geometry.size.width)