How to customize NavigationLink accessory views in SwiftUI

In UIKit, UITableViewCell has a customizable accessory view. You can use one of the few accessory options that is provided by iOS by setting the accessoryType property, or you can provide a custom view using accessoryView, which can be any UIView. The equivalent of constructing a UITableViewCell with a chevron accessory in SwiftUI is using a NavigationLink. Unfortunately, however, SwiftUI does not provide an API to customize the accessory view for a NavigationLink — you are stuck with the default chevron.

Leading by example, UIKit demonstrates the need for different accessory views to communicate to the user what to expect when they tap a table view cell. You can find all the different accessory types in use in the apps built-in to iOS — chevrons, the information icons (“i” with a circle), and checkmarks. It is very common for apps to customize the accessory view for cells in a UITableView or views in a SwiftUI List. It is surprising that SwiftUI still lacks an official API for this.

What’s worse than a default chevron that cannot be customized is that there is also no API to opt-out and simply hide it. And what’s even worse than that is that the default chevron for a NavigationLink is different than the chevron provided by SFSymbols. If used together, they clash and it’s ugly.

So, like many things in SwiftUI, we have to resort to hacks and obscure workarounds to achieve decades-old UIKit behavior. The best way I’ve found to hide the default chevron in a NavigationLink is to hide the entire thing underneath another view using a ZStack.

Suppose we are using a NavigationLink to display an “About” view in our app:

// HACK: ZStack with zero opacity + EmptyView
// Hides default chevron accessory view for NavigationLink
ZStack {
    NavigationLink {
        AboutView()
    } label: {
        EmptyView()
    }
    .opacity(0)

    Label(title: "About", icon: Image(systemName: "info.circle"))
}

This allows you to provide an entirely custom View for the NavigationLink. In this case, that’s the foremost Label in the ZStack. Obviously, you would not want to copy and paste this snippet every time you need a NavigationLink, so we can write a better version of NavigationLink to encapsulate this for us. We can mimic the NavigationLink API.

struct BetterNavigationLink<Label: View, Destination: View>: View {
    let label: Label
    let destination: Destination

    init(@ViewBuilder label: () -> Label,
         @ViewBuilder destination: () -> Destination) {
        self.label = label()
        self.destination = destination()
    }

    var body: some View {
        // HACK: ZStack with zero opacity + EmptyView
        // Hides default chevron accessory view for NavigationLink
        ZStack {
            NavigationLink {
                self.destination
            } label: {
                EmptyView()
            }
            .opacity(0)

            self.label
        }
    }
}

With that, we have a drop-in replacement for NavigationLink and can update all call sites to use BetterNavigationLink instead.

BetterNavigationLink {
    Label(title: "About", icon: Image(systemName: "info.circle"))
} destination: {
    AboutView()
}

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I think NavigationLink can be made significantly better with some small changes. First, I do not think there should be any accessory view by default — accessories should be opt-in, just like with UITableViewCell. Second, I think NavigationLink should allow you to set any SFSymbol as the accessory. Perhaps this could be a new view modifier for NavigationLink.

NavigationLink {
    AboutView()
} label: {
    Text("About")
}
.navigationAccessory(Image(systemName: "info.circle"))

Wouldn’t that be nice?

How to customize NavigationLink accessory views in SwiftUI

18 July 2023

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