How to dynamically change between VStack and HStack

Paul Hudson @twostraws December 1st 2022

Updated for Xcode 14.1

New in iOS 16

SwiftUI’s AnyLayout struct allows us to switch between HStack and VStack freely, based on whatever environment context we want to take into account – just remember to use the Layout-conforming variants of each.

For example, we might want to show a group of images horizontally when we’re in a regular horizontal size class, or vertically otherwise, like this:

struct ContentView: View {
    @Environment(\.horizontalSizeClass) var horizontalSizeClass

    var body: some View {
        let layout = horizontalSizeClass == .regular ? AnyLayout(HStackLayout()) : AnyLayout(VStackLayout())

        layout {
            Image(systemName: "1.circle")
            Image(systemName: "2.circle")
            Image(systemName: "3.circle")
        }
        .font(.largeTitle)
    }
}

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Tip: Unlike using AnyView, AnyLayout doesn’t incur any performance impact, and won’t discard any of the state of its child views.

Alternatively, we could flip the axis when the user’s Dynamic Type size goes beyond a certain size:

struct ContentView: View {
    @Environment(\.dynamicTypeSize) var dynamicTypeSize

    var body: some View {
        let layout = dynamicTypeSize <= .xxxLarge ? AnyLayout(HStackLayout()) : AnyLayout(VStackLayout())

        layout {
            Image(systemName: "1.circle")
            Image(systemName: "2.circle")
            Image(systemName: "3.circle")
        }
        .font(.largeTitle)
    }
}

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As well as VStackLayout and HStackLayout, you can also use ZStackLayout and GridLayout.

Tip: Any grid rows that are used in non-grid layouts don’t do anything – they become the same as using Group.