SwiftUI – Open a specific View when user opens a Push Notification

You need some sort of shared state that you can modify that SwiftUI knows to react to. An ObservableObject is perfect for this:

class AppState: ObservableObject {
    static let shared = AppState()
    @Published var pageToNavigationTo : String?
}

Then, to listen to it and respond to it, you can do a couple different methods in your main view.

Option 1 — NavigationLink binding based on the value of the ObservedObject:

struct ContentView : View {
    @ObservedObject var appState = AppState.shared //<-- note this
    @State var navigate = false
    
    var pushNavigationBinding : Binding<Bool> {
        .init { () -> Bool in
            appState.pageToNavigationTo != nil
        } set: { (newValue) in
            if !newValue { appState.pageToNavigationTo = nil }
        }
    }
    
    var body: some View {
        NavigationView {
            Text("My content")
                .overlay(NavigationLink(destination: Dest(message: appState.pageToNavigationTo ?? ""),
                                        isActive: pushNavigationBinding) {
                    EmptyView()
                })
        }
    }
}

struct Dest : View {
    var message : String
    var body: some View {
        Text("\(message)")
    }
}

Or, you could use onReceive:

struct ContentView : View {
    @ObservedObject var appState = AppState.shared
    @State var navigate = false
    
    var body: some View {
        NavigationView {
            VStack {
                if navigate {
                    NavigationLink(destination: Text("Test"), isActive: $navigate ) {
                        EmptyView()
                    }
                }
                Text("My content")
                    .onReceive(appState.$pageToNavigationTo) { (nav) in
                        if nav != nil { navigate = true }
                    }
            }
        }
    }
}

I’ll leave the implementation details of your specific NavigationView, NavigationLink, TabView, etc to you, but this should get you started.

Finally, a fully-functional minimal example that mocks a notification and shows how the navigation view:

class AppDelegate: NSObject, UIApplicationDelegate, UNUserNotificationCenterDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
     
        DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
            print("Dispatch")
            AppState.shared.pageToNavigationTo = "test"
        }
        
        return true
    }
}

class AppState: ObservableObject {
    static let shared = AppState()
    @Published var pageToNavigationTo : String?
}

@main
struct MultiWindowApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

struct ContentView : View {
    @ObservedObject var appState = AppState.shared
    @State var navigate = false
    
    var pushNavigationBinding : Binding<Bool> {
        .init { () -> Bool in
            appState.pageToNavigationTo != nil
        } set: { (newValue) in
            if !newValue { appState.pageToNavigationTo = nil }
        }
    }
    
    var body: some View {
        NavigationView {
            Text("My content")
                .overlay(NavigationLink(destination: Dest(message: appState.pageToNavigationTo ?? ""),
                                        isActive: pushNavigationBinding) {
                    EmptyView()
                })
        }
    }
}


struct Dest : View {
    var message : String
    var body: some View {
        Text("\(message)")
    }
}