View pops automatically when in navigation view

Question

Created Nov ’21

Replies 3

Boosts 0

Participants 3

I want to have a navigation view with 3 views where the third view need to pop to the root view when button is clicked.Here is the code I'm implementing:

import SwiftUI

class NavigationHelper: ObservableObject {
    @Published var selection:String? = nil
}

struct View1: View {
    
    @ObservedObject var navigationHelper:NavigationHelper = NavigationHelper()
    
    var body: some View {
        NavigationView{
            VStack {
                Text("View1")
                    .padding()
                
                Button {
                    navigationHelper.selection = "View2"
                } label: {
                    Text("Go To View2")
                }

                
                NavigationLink(tag: "View2", selection: $navigationHelper.selection) {
                    View2()
                } label: {
                    EmptyView()
                }.isDetailLink(false)
            }
        }.environmentObject(navigationHelper)

    }
}

struct View2: View {
    @EnvironmentObject var navigationHelper:NavigationHelper
    
    var body: some View {
        VStack {
            Text("View2")
                .padding()
            
            Button {
                navigationHelper.selection = "View3"
            } label: {
                Text("Go To View3")
            }
            
            
            NavigationLink(tag: "View3", selection: $navigationHelper.selection) {
                View3()
            } label: {
                EmptyView()
            }
        }
    }
}


struct View3: View {
    @EnvironmentObject var navigationHelper:NavigationHelper
    
    var body: some View {
        VStack {
            Text("View3")
                .padding()
            
            Button {
                navigationHelper.selection = nil
            } label: {
                Text("Go To Root")
            }
        }
    }
}

When View3 is opened it pops back to View1 when opened and cannot understand why? For some reason the selection property becomes nil maybe.

Boost

Answer 1

Claude31 OP

Nov ’21

Could you show the definition of your root view ? What do you expect by setting to nil ?

0

Answer 2

OOPer OP

Nov ’21

For some reason the selection property becomes nil maybe.

Your guess seems to be wrong.

The most critical thing in your code is that a single selection: is shared between two NavigationLinks in different levels of navigation.

When you execute this line of code:

navigationHelper.selection = "View3"

The NavigationLink in View1 gets inactive:

                //↓This NavigationLink gets inactive when `navigationHelper.selection` has any other value than `"View2"`
                NavigationLink(tag: "View2", selection: $navigationHelper.selection) {
                    View2()
                } label: {
                    EmptyView()
                }.isDetailLink(false)

So, one possible workaround would be something like this:

import SwiftUI

class NavigationHelper: ObservableObject {
    @Published var view2IsActive: Bool = false
    @Published var view3IsActive: Bool = false
}

struct View1: View {
    
    @ObservedObject var navigationHelper:NavigationHelper = NavigationHelper()
    
    var body: some View {
        NavigationView{
            VStack {
                Text("View1")
                    .padding()
                
                Button {
                    navigationHelper.view2IsActive = true
                } label: {
                    Text("Go To View2")
                }

                
                NavigationLink.init(isActive: $navigationHelper.view2IsActive) {
                    View2()
                } label: {
                    EmptyView()
                }.isDetailLink(false)
            }
        }.environmentObject(navigationHelper)

    }
}

struct View2: View {
    @EnvironmentObject var navigationHelper:NavigationHelper
    
    var body: some View {
        VStack {
            Text("View2")
                .padding()
            
            Button {
                navigationHelper.view3IsActive = true
            } label: {
                Text("Go To View3")
            }
            
            
            NavigationLink(isActive: $navigationHelper.view3IsActive) {
                View3()
            } label: {
                EmptyView()
            }
        }
    }
}


struct View3: View {
    @EnvironmentObject var navigationHelper:NavigationHelper
    
    var body: some View {
        VStack {
            Text("View3")
                .padding()
            
            Button {
                navigationHelper.view2IsActive = false
            } label: {
                Text("Go To Root")
            }
        }
    }
}

0

Answer 3

Rado Gotinoto Dev4e OP

Nov ’21

By Go to Root view I mean go back to View1

0