Should onNavigate be called when NavigationLink becomes active?

[eiskalt]

This is more of a general question before I raise an issue.

According to the documentation for onNavigate it states A closure that executes when the link becomes active or inactive with a boolean that describes if the link was activated or not..

I have been unable to get onNavigate to execute on any active when changing the route value (even though the navigation does occur) and the closure boolean has never been true.

Example:
NavigationLink(unwrapping: $route, case: /Route.a) { ... } onNavigate: { isActive in print("This is never called on activation and isActive has never been true") } ...

Note: It works fine when navigating back and the boolean is false as according to: #10

[stephencelis]

@eiskalt Can you provide a full example? You could even zip up a project and attach it here.

You might also want to check out the demos here: https://github.com/pointfreeco/swiftui-navigation/tree/7a61fb419997f56bd9928c7b405fc7557a60d4bd/Examples

Both the Inventory app and Case Studies include uses of NavigationLink with enum values. For example: https://github.com/pointfreeco/swiftui-navigation/blob/7a61fb419997f56bd9928c7b405fc7557a60d4bd/Examples/CaseStudies/08-Routing.swift#L50-L58

[eiskalt]

Ah that will be the case!
I am modifying the state directly which is why onNavigate is not called.
That makes sense and (I had accidentally assume it was called on all events which cause navigation).

Thanks for the help!

[eiskalt]

I have been trying to get more complex deeplinking working. For example deeplinking into a deep screen while setting up the navigation stack. This could be a stack that is 5 steps deep and we deeplink into the 4th level.

The issue I am getting is that I am only able to go on NavigationLink deep. I believe this is due to the SwiftUI lifecycle and the way performing a NavigationLink is handled, it does not allow any deeper NavigationLinks to be executed.

I have tried a variety of aspect and the only solution I have got working (which isn't really a solution) is to dispatch a change to the route after 1 second in onAppear. I believe this is since the UI navigation has completed at that time and it allow for another link to dispatch. Note: Turning off animation on NavigationLink performing does not help.

While this is not related to this framework it would be greatly appreciated if anyone has any ideas or solutions to this problem.

Please see below for an attached code example which came simply be created inside a NavigationView and called with the following deeplink TestRouter(route: .first(.second(.third))) which only takes the user one level deep.

import SwiftUI
import SwiftUINavigation

struct TestRouter: View {
    
    enum Route {
        case first(FirstRoute? = nil)
        
        enum FirstRoute {
            case second(SecondRoute? = nil)
            
            enum SecondRoute {
                case third
            }
        }
    }
    
    @State var route: Route?

    public var body: some View {
        
        VStack {
            
            Text("Initial Screen")
            Button("Go to first screen") {
                route = .first()
            }
            
            NavigationLink(unwrapping: $route, case: /Route.first) { firstRoute in
                
                Text("First Screen")
                Button("Go to second screen") {
                    route = .first(.second())
                }
                
                NavigationLink(unwrapping: $route, case: /Route.first) { secondRoute in
                    
                    Text("Second Screen")
                    Button("Go to third screen") {
                        route = .first(.second(.third))
                    }
                    
                    NavigationLink(unwrapping: $route, case: /Route.first) { _ in
                        Text("Third Screen")
                    } onNavigate: { isActive in
                        self.route = isActive ? .first() : nil
                    } label: {
                        EmptyView()
                    }
                    
                } onNavigate: { isActive in
                    self.route = isActive ? .first(.second()) : .first()
                } label: {
                    EmptyView()
                }
                
            } onNavigate: { isActive in
                self.route = isActive ? .first() : nil
            } label: {
                EmptyView()
            }
        }
    }
    
}

Thanks for the time!

[stephencelis]

The issue I am getting is that I am only able to go on NavigationLink deep. I believe this is due to the SwiftUI lifecycle and the way performing a NavigationLink is handled, it does not allow any deeper NavigationLinks to be executed.

This is unfortunately a longstanding bug in SwiftUI that existed in the first release and still exists today. Here's a Stack Overflow with potential workarounds that involve staggering the deep linking over multiple steps:

https://stackoverflow.com/questions/59403359/deep-programmatic-swiftui-navigationview-navigation

We hope it will eventually be fixed 😞

[eiskalt]

Thanks a lot for the help. I was hoping there was a magic answer but for now it appears I will have to do that very hacky solution.

This library has been super useful so far and the video series on it was a great help!

[eiskalt]

If anyone has been attempting deeplinking (or similar multi-level actions) I have found a potential solution. That is adding isDetailLink(false) to your NavigationLinks.

Note that this is not available for other platforms and I have not tested it in multi-column navigation which it appears this is meant for.