testSelect

testSelect.swift

import SwiftUI

struct ContentView: View {
    
    @State var editMode = EditMode.inactive
    
    @State private var selection = Set<String>()
    
    let names = [
        "Cyril",
        "Lana",
        "Mallory",
        "Sterling"
    ]
    
    var body: some View {
        NavigationView {
            let navTitle = editMode == .inactive || selection.isEmpty ? "Library" : "\(selection.count) selected"
            List(names, id: \.self, selection: $selection) { name in
                Text(name)
                    //On iOS>=16 shows single item contextMenu with custom Preview, otherwise old contextMenu
                    .modifier(SingleItemContextMenu(name: name))
            }
            .modifier(MultiItemContextMenu())  //On iOS>=16 shows contextMenu for multi-item select, otherwise nothing
            .navigationTitle(navTitle)
            .modifier(TrailingToolbar(editMode: $editMode)) //On iOS>=16 adds Select button, otherwise just the Sort button
            .environment(\.editMode, $editMode)
        }
    }
}

struct TrailingToolbar : ViewModifier {
    
    @Binding var editMode: EditMode
    
    func body(content: Content) -> some View {
        let sortButton = Menu {
            Button("Title") {}
            Button("Artist") {}
        } label: {
            Text("Sort")
        }
        let selectButton = Button(editMode == .inactive ? "Select" : "Done") {
            withAnimation {
                if editMode == .inactive {
                    editMode = .active
                } else {
                    editMode = .inactive
                }
            }
        }
        return content
            .toolbar {
                ToolbarItemGroup(placement: .navigationBarTrailing) {
                    if #available(iOS 16, *) {
                        if editMode == .active {
                            selectButton
                        }
                        Menu {
                            if editMode == .inactive {
                                selectButton
                            }
                            sortButton
                        } label: {
                            Button{} label: {
                                Image(systemName: "ellipsis.circle")
                            }
                        }
                        
                    } else {
                        sortButton
                    }
                }
            }
    }
}

extension View {
    func trailingToolbar(editMode: Binding<EditMode>) -> some View {
        
        let selectButton = Button(editMode.wrappedValue == .inactive ? "Select" : "Done") {
            withAnimation {
                if editMode.wrappedValue == .inactive {
                    editMode.wrappedValue = .active
                } else {
                    editMode.wrappedValue = .inactive
                }
            }
        }
        return toolbar {
            ToolbarItem(placement: .navigationBarTrailing) {
                if #available(iOS 16, *) {
                    
                } else {
                    
                }
            }
        }
    }
}


struct SingleItemContextMenu: ViewModifier {
    let name: String
    
    @ViewBuilder var menuItems: some View {
        Button {
            print("Change country setting")
        } label: {
            Label("Choose Country", systemImage: "globe")
        }
        
        Button {
            print("Enable geolocation")
        } label: {
            Label("Detect Location", systemImage: "location.circle")
        }
    }
    func body(content: Content) -> some View {
        if #available(iOS 16, *) {
            content.contextMenu {
                menuItems
            } preview: {
                VStack {
                    Text(name)
                        .padding(.bottom, 8)
                    Image(systemName: "square.stack")
                }
                .frame(width: 200, height: 200)
            }
        } else {
            content.contextMenu {
                menuItems
            }
        }
        
    }
}

struct MultiItemContextMenu: ViewModifier {
    func body(content: Content) -> some View {
        if #available(iOS 16, *) {
            content.contextMenu(forSelectionType: String.self) { items in
                if items.count > 1 { // Multi-item menu.
                    Button("Copy") { }
                    Button("New Folder With Selection") { }
                    Button("Delete Selected", role: .destructive) { }
                }
            }
        } else {
            content
        }
    }
}



struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}