SwiftUI @State var not sync in .popover

Question

Created Jun ’25

Replies 4

Boosts 0

Participants 4

struct ContentView: View {
    @State var visable: Bool = false
    @State var visableHiddenMenu: Bool = false

    var body: some View {
        VStack {
            Button("xxxx") {
                visableHiddenMenu = true
                print("visableHiddenMenu \(visableHiddenMenu)")
                visable.toggle()
            }
            .popover(isPresented: $visable) {
                VStack {
                    let _ = print("visableHiddenMenu2 \(visableHiddenMenu)")
                    Text("xxxx")
                }
                .onAppear {
                    print("appear \(visableHiddenMenu)")
                    visableHiddenMenu = visableHiddenMenu
                }
            }
        }
        .padding()
    }
}

the print is

visableHiddenMenu true
visableHiddenMenu2 false
appear true

so why visableHiddenMenu2 print false?

Boost

Answer 1

jlilest OP

Jun ’25

That code is running in willSet for the property.

0

Answer 2

Claude31 OP

Jun ’25

Really strange. Not sure of the explanation, but looks like the VStack is not reevaluated when popover is called.

But, if added a Text in the VStack, and it works OK. VStack is reevaluated.

    var body: some View {
        VStack {
            Button("xxxx") {
                print("Button")
                visableHiddenMenu = true
                print("visableHiddenMenu \(visableHiddenMenu)")
                visable.toggle()
            }
            .popover(isPresented: $visable) {
                VStack {
                    let _ = print("visableHiddenMenu2 \(visableHiddenMenu)")
                    Text("Popover presented \(visableHiddenMenu)")
                }
                .onAppear {
                    print("appear \(visableHiddenMenu)")
                    visableHiddenMenu = visableHiddenMenu
                }
            }
            Text("Popover visible \(visableHiddenMenu)")
        }
        .padding()
    }

In log:

Button
visableHiddenMenu true
visableHiddenMenu2 true
appear true
visableHiddenMenu2 true

Note that visableHiddenMenu2 true appears twice, showing Stack is reevaluated.

PS: what is the purpose of line 19 ?

1

Answer 3

jlilest OP

Jun ’25

The notification happens using publishing. Only items included in the publishing notification will reflect the new state.

0

Answer 4

DTS Engineer OP

Apple

Jun ’25

This is odd, I notice you get the expected value when the content of the Popover is in an enclosing struct. For example:

struct SheetView: View {
    @Binding var visableHiddenMenu: Bool

    var body: some View {
        VStack {
            let _ = Self._printChanges()
            Text("xxxx")
        }
        .printOutput(visableHiddenMenu)
        .onAppear {
            print("appear \(visableHiddenMenu)")
            visableHiddenMenu = visableHiddenMenu
        }
    }
}
struct ContentView: View {
    @State private var visable = false
    @State private var visableHiddenMenu = false

    var body: some View {
        VStack {
            let _ = Self._printChanges()

            Button("xxxx") {
                visableHiddenMenu = true
                print("visableHiddenMenu \(visableHiddenMenu)")
                visable.toggle()
            }
            .popover(isPresented: $visable) {
                SheetView(visableHiddenMenu: $visableHiddenMenu)
            }
        }
        .padding()
    }
}

extension View {
    func printOutput(_ value: Any) -> Self {
        print("visableHiddenMenu2 \(value)")
        return self
    }
}

Could you please open a bug report, include the code snippet that reproduces the issue and post the FB number here once you do. Bug Reporting: How and Why? has tips on creating your bug report.

1