macos - How to get a sidebar open state in Swift?

Question

I have a SwiftUI app with a sidebar (NavigationView) I'm able to toggle the sidebar via hotkeys using SidebarCommands() and programmatically via the following function:

func toggleSidebar() {
  NSApp.keyWindow?.firstResponder?.tryToPerform(#selector(NSSplitViewController.toggleSidebar(_:)), with: nil)
}

I have this attached to a button action, but I want to highlight the button in a different color when sidebar is open.

How can I get the state of the sidebar?

question from:https://stackoverflow.com/questions/65857810/how-to-get-a-sidebar-open-state-in-swift

Answer 1

Half of a solution: (reason it's half see bottom)

---

Assuming you have a ToolbarItem:

ToolbarItem {
    Button(
        action: toggleSidebar, 
        label: { Label("Sidebar", systemImage: "sidebar.left") }
    )
}

You could add a Bool value in your view @State private var sidebarOpened: Bool = true

Then you can toggle that value with the same button:

ToolbarItem {
    Button(
        action: {
            toggleSidebar()
            sidebarOpened.toggle()
        }
        label: { Label("Sidebar", systemImage: "sidebar.left") }
    )
}

Now you can set the color of your label based on sidebarOpened:

label: { Label("Sidebar", systemImage: "sidebar.left") }
.foregroundColor(sidebarOpened ? .red : .secondary)

---

Note:

This method doesn't really know if the sidebar is open or not, instead it works based on if the button was clicked, so it gives you different result if you left the sidebar opened or not the last time you closed the app.

It would be better to have a value of whether the sidebar is open or not, which I don't think there's a native SwfitUI solution yet. Probably need to check AppKit NSSplitView.