Greetings, traveler!

In SwiftUI, both .onAppear and .task are commonly used to perform actions when a view becomes visible. In most cases they work exactly as expected — the moment a view appears in the hierarchy, the modifier is triggered.

However, there are a couple of situations where these callbacks are not executed, even though the code may look correct on the surface. Most notably this happens when using Group and EmptyView.

Group Does Not Produce a Real View

Group is a structural container and does not produce its own view in the hierarchy. It simply evaluates its children and forwards them. When none of the children are present, SwiftUI collapses the whole group and nothing is rendered.

struct ContentView: View {
    @State private var showContent = false

    var body: some View {
        Group {
            if showContent {
                Text("Hello")
            }
        }
        .onAppear {
            print("onAppear called")
        }
    }
}

struct ContentView: View {
    @State private var showContent = false

    var body: some View {
        Group {
            if showContent {
                Text("Hello")
            }
        }
        .onAppear {
            print("onAppear called")
        }
    }
}

In this example, onAppear is not called while showContent is false, because the Group has no content and does not appear in the view hierarchy. From SwiftUI’s point of view, there is nothing to “appear”.

The same behavior also applies to .task.

EmptyView Is Not Inserted Either

A natural attempt to workaround this is to insert EmptyView() as a placeholder:

Group {
    if showContent {
        Text("Hello")
    } else {
        EmptyView()
    }
}
.onAppear {
    print("onAppear called")
}

Group {
    if showContent {
        Text("Hello")
    } else {
        EmptyView()
    }
}
.onAppear {
    print("onAppear called")
}

This does not fix the issue. EmptyView is only a stub that satisfies Swift’s type system and layout requirements — it is not actually inserted into the rendered hierarchy. Therefore, both .onAppear and .task still won’t be executed.

Workaround: Use a Real View (e.g. Color.clear or ZStack)

To force the view tree to contain an actual view (even when there is no content), use something that produces a real view like Color.clear:

Group {
    if showContent {
        Text("Hello")
    } else {
        Color.clear // forces an actual view to appear
    }
}
.onAppear {
    print("onAppear called")
}

Group {
    if showContent {
        Text("Hello")
    } else {
        Color.clear // forces an actual view to appear
    }
}
.onAppear {
    print("onAppear called")
}

or with .task:

Group {
    if showContent {
        Text("Hello")
    } else {
        Color.clear
    }
}
.task(id: showContent) {
    print("Task executed when view appears or state changes")
}

Group {
    if showContent {
        Text("Hello")
    } else {
        Color.clear
    }
}
.task(id: showContent) {
    print("Task executed when view appears or state changes")
}

Color.clear still renders a view (with no visible pixels), so SwiftUI includes it in the hierarchy and correctly triggers onAppear and task.

Another way is to use ZStack:

ZStack {
    if showContent {
        Text("Hello")
    }
}
.task(id: showContent) {
    print("Task executed when view appears or state changes")
}

ZStack {
    if showContent {
        Text("Hello")
    }
}
.task(id: showContent) {
    print("Task executed when view appears or state changes")
}

Conclusion

onAppear and task are reliable ways to start work when a view becomes visible — but only when a real view actually appears. Both Group and EmptyView are structural constructs that may result in no rendered view, which prevents these modifiers from being called. When you need the callback to fire even in a “no-content” state, ensure that the hierarchy contains a real view, such as Color.clear.

If you keep that in mind, these modifiers remain predictable and safe to use — even in conditional layouts.