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SwiftUI: NavigationDestinationLink deprecated

Tags:

ios

swift

swiftui

After installing Xcode 11 beta 5 this morning, I noticed that NavigationDestinationLink was deprecated in favor of NavigationLink.

Also, that's what Apple says about it in the release notes:

NavigationDestinationLink and DynamicNavigationDestinationLink are deprecated; their functionality is now included in NavigationLink. (50630794)

The way I use NavigationDestinationLink is to programmatically push a new view into the stack via self.link.presented?.value = true. That functionality doesn't seem to be present in NavigationLink.

Any idea anyone? I would rather not use NavigationDestinationLink anymore as it's deprecated...

Thank you!

UPDATE: Actually, the NavigationDestinationLink way does not work anymore so I guess we have no way of pushing programmatically anymore?

UPDATE 2:

NavigationLink(destination: CustomView(), isActive: $isActive) {
    return Text("")
}

This works but when you pass isActive to true, any state update will trigger this code and push over and over... Also, if you pass it back to false, it will pop the view. Not only updates, if you set isActive to true, it will push the view (good) and if we press the back button, it will go back then immediately push again since it's still true. Playing with onAppear was my hope but it's not called when going back to it... I'm not sure how we're supposed to use this.

like image 794
Benjamin Clanet Avatar asked Jul 30 '19 14:07

Benjamin Clanet


2 Answers

After spending some time with NavigationLink(destination:isActive), I am liking it a lot more than the old NavigationDestinationLink. The old view was a little confusing, while the new approach seems much more elegant. And once I figure out how to push without animations, it would make state restoration at application launch very easy.

There is one problem though, a big and ugly bug. :-(

enter image description here

Pushing a view programatically works fine, and popping it programatically does too. The problem starts when we use the BACK button in the pushed view which behaves oddly every other time. The first time the view is popped, the view pops and pushes again immediately. The second time around it works fine. Then the third time it starts all over again.

I have created a bug report (number here). I recommend you do the same and reference my number too, to help Apple group them together and get more attention to the problem.

I designed a workaround, that basically consists of replacing the default Back button, with our own:

class Model: ObservableObject {
    @Published var pushed = false
}

struct ContentView: View {
    @EnvironmentObject var model: Model

    var body: some View {
        NavigationView {
            VStack {
                Button("Push") {
                    // view pushed programmatically
                    self.model.pushed = true
                }

                NavigationLink(destination: DetailView(), isActive: $model.pushed) { EmptyView() }
            }
        }
    }
}

struct DetailView: View {
    @EnvironmentObject var model: Model

    var body: some View {
        Button("Bring me Back (programatically)") {
            // view popped programmatically
            self.model.pushed = false
        }
        // workaround
        .navigationBarBackButtonHidden(true) // not needed, but just in case
        .navigationBarItems(leading: MyBackButton(label: "Back!") {
            self.model.pushed = false
        })
    }
}

struct MyBackButton: View {
    let label: String
    let closure: () -> ()

    var body: some View {
        Button(action: { self.closure() }) {
            HStack {
                Image(systemName: "chevron.left")
                Text(label)
            }
        }
    }
}
like image 145
kontiki Avatar answered Sep 28 '22 14:09

kontiki


To improve the workaround without replacing the back button with a custom one, you can use the code above :

NavigationLink(destination: Test().onAppear(perform: {
    self.editPushed = nil
}), tag: 1, selection: self.$editPushed) {
    Button(action: {
        self.editPushed = 1
    }) {
        Image(systemName: "plus.app.fill")
            .font(.title)
    }
}

The onAppear block will erase the selection value preventing to display the detail view twice

like image 34
CeDerache Avatar answered Sep 28 '22 14:09

CeDerache