List selection as Set<String> - how to use? - swift

Question

Am playing around with SwiftUI and am obviously not getting it.
Basic example which works and is just displaying the selected name.
struct ContentView: View {
let names = ["Joe", "Jim", "Paul"]
#State var selectedName = Set<String>()
var body: some View {
VStack {
List(names, id: \.self, selection: $selectedName) { name in
Text(name)
}
if !selectedName.isEmpty {
Text(selectedName.first!) // <-- this line
}
}
}
}
What I want is a textfield where that name can be changed. Tried many ways but getting another error every time.
TextField("Name", text: $selectedName)
Gives this error: Cannot convert value of type 'Binding<Set<String>>' to expected argument type 'Binding<String>'
TextField("Name", text: $selectedName.first!)
Cannot force unwrap value of non-optional type 'Binding<((String) throws -> Bool) throws -> String?>'
How would I do this?

Answer 1

You may make a binding by yourself:
TextField("Name", text: Binding<String>(get: {self.selectedName.first!}, set: { _ in}) )

Answer 2

Obviously you can't pass Binding<Set<String>> to Binding<String>. Here gives you an idea or solution to change selectedName variable using TextField:
I added a new variable which is Binding<String>. Then I change the selectedName inside the TextField's onCommit closure.
struct ContentView: View {
let names = ["Joe", "Jim", "Paul"]
#State var selectedName = Set<String>()
#State var textFieldName = ""
var body: some View {
VStack {
List(names, id: \.self, selection: $selectedName) { name in
Text(name)
}
if !selectedName.isEmpty {
Text(selectedName.first!)
}
Text(textFieldName)
TextField("Name", text: $textFieldName, onEditingChanged: { (Bool) in
//onEditing
}) {
//onCommit
self.selectedName.insert(self.textFieldName)
}
}
}
}

Answer 3

Ok, here is my alternate if I'd needed to edit some value of names having in one screen and list and edit field and make them all synchronised and not confuse each other.
Here is full testable module (tested on Xcode 11.2/iOS 13.2). As I tested it for iOS there are API requirement for put List into EditMode to process selection, so this included.
struct TestChangeSelectedItem: View {
#State var names = ["Joe", "Jim", "Paul"] // made modifiable
#State var selectedName: String? = nil // only one can be edited, so single selection
#State var editMode: EditMode = .active // Tested for iOS, so it is needed
var body: some View {
VStack {
List(selection: $selectedName) {
ForEach(names, id: \.self) { name in
Text(name)
}
}
.environment(\.editMode, $editMode) // Tested for iOS, so it is needed
if selectedName != nil {
Divider()
Text(selectedName!) // Left to see updates for selection
editor(for: selectedName!) // Separated to make more clear
}
}
}
private func editor(for selection: String) -> some View {
let index = names.firstIndex(of: selection)!
var editedValue = selection // local to avoid cycling in refresh
return HStack {
Text("New name:")
TextField("Name", text: Binding<String>(get: { editedValue }, set: { editedValue = $0}), onCommit: {
self.names[index] = editedValue
self.selectedName = editedValue
})
}
}
}
struct TestChangeSelectedItem_Previews: PreviewProvider {
static var previews: some View {
TestChangeSelectedItem()
}
}