I want to programmatically select a specific NavigationLink
in a NavigationView
/ List
.
The following code works fine on iPhones both in portrait or landscape mode == in situations where the List is not permanently visible besides its destination view.
Code:
struct ContentView: View {
private let listItems = [ListItem(), ListItem(), ListItem()]
@State var selection: Int? = 0
var body: some View {
NavigationView {
List(listItems.indices) {
index in
let item = listItems[index]
let isSelected = (selection ?? -1) == index
NavigationLink(destination: Text("Destination \(index)"),
tag: index,
selection: $selection) {
Text("\(item.name) \(index) \(isSelected ? "selected" : "")")
}
}
}
.listStyle(SidebarListStyle())
.onAppear(perform: {
DispatchQueue.main.asyncAfter(deadline: .now() + 1.0, execute: {
selection = 2
})
})
}
}
struct ListItem: Identifiable {
var id = UUID()
var name: String = "Some Item"
}
But it fails on iPads in landscape mode: While the navigation itself works (destination is shown correctly), the NavigationLink
remains unselected.
ā How can I select the NavigationLink in a way it appears selected on iPads too?
Here is possible approach. The idea is to programmatically activate navigation link via view model, but separate model-level selection and presentation (own by link) selection.
Tested with Xcode 12b3 / iOS+iPadOS 14.
class SelectionViewModel: ObservableObject {
var currentRow: Int = -1 {
didSet {
self.selection = currentRow
}
}
@Published var selection: Int? = nil
}
struct SidebarContentView: View {
@StateObject var vm = SelectionViewModel()
private let listItems = [ListItem(), ListItem(), ListItem()]
var body: some View {
NavigationView {
List(listItems.indices) {
index in
let item = listItems[index]
let isSelected = vm.currentRow == index
Button("\(item.name) \(index) \(isSelected ? "selected" : "")") { vm.currentRow = index }
.background (
NavigationLink(destination: Text("Destination \(index) selected: \(vm.currentRow)"),
tag: index,
selection: $vm.selection) {
EmptyView()
}.hidden()
)
}
}
.listStyle(SidebarListStyle())
.onAppear(perform: {
DispatchQueue.main.asyncAfter(deadline: .now() + 1.0, execute: {
vm.currentRow = 2
})
})
}
}