I have the following lines of code for showing a list of friends. import SwiftUI struct ContentView: View { @State var users = ["Susan", "Kate", "Natalie", "Kimberly", "Taylor", "Sarah", "Nancy", "Katherine", "Nicole", "Linda", "Jane", "Mary", "Olivia", "Barbara"] @State var editMode = EditMode.inactive var body: some View { NavigationView { List { ForEach(users, id: \.self) { user in Text(user) } } .navigationBarTitle("Friends") .environment(\.editMode, $editMode) .navigationBarItems(leading: Button("Edit", action: { if self.editMode == .active { self.editMode = .inactive } else { self.editMode = .active } })) } } } If you see the code at the bottom, I have four lines just in order to change the value of editMode. Does SwiftUI have something like showDetails.toggle() where showDetails is a Boolean variable? Muchos thankos.

I have the following lines of code to work with a list of strings. import SwiftUI struct ContentView: View { @State private var users = ["George", "Kenny", "Susan", "Natalie"] var body: some View { NavigationView { List { ForEach(users, id: \.self) { user in Text(user) } .onDelete(perform: delete) } .navigationBarTitle("My family") .toolbar { EditButton() } } } func delete(at offsets: IndexSet) { users.remove(atOffsets: offsets) } } Now, I'm doing the following out of curiosity. Now, I have a button in naviationBarItems. And I wonder if I can turn on and off the edit feature of the list with the button? struct ContentView: View { @State private var users = ["George", "Kenny", "Susan", "Natalie"] var body: some View { NavigationView { List { ForEach(users, id: \.self) { user in Text(user) } } .navigationBarTitle("My family") .navigationBarItems(trailing: Button(action: { print("Edit button pressed...") }) { Text("Edit") } ) } } } Muchos thankos.

I just want to show a simple navigation title like the following. import SwiftUI struct ContentView: View { var body: some View { NavigationView { ZStack { Color.red.edgesIgnoringSafeArea(.all) Text("Hello") } .navigationTitle("GGG") .navigationBarTitleDisplayMode(.inline) .navigationBarHidden(false) } } } And I get a bunch of mumbo jumbo auto-layout warnings (Unable to simultaneously satisfy constraints...) in Console. If I comment out the navigationTitle line, I won't get them. I have never seen those messages in showing a navigation title when writing code with UIKit. What am I doing wrong? Muchos thankos

I'm trying to understand how Combine works. The following is my sample code. import UIKit import Combine class ViewController: UIViewController { // MARK: - Variables var cancellable: AnyCancellable? // MARK: - IBAction @IBAction func buttonTapped(_ sender: UIButton) { currentValueSubject.send(20) } // MARK: - Life cycle var currentValueSubject = CurrentValueSubject<Int, Never>(1) override func viewDidLoad() { super.viewDidLoad() let cancellable = currentValueSubject .sink { value in print("New value: \(value)") } currentValueSubject.send(5) currentValueSubject.send(10) //currentValueSubject.send(completion: .finished) currentValueSubject.send(15) //cancellable.cancel() } } If I run it with the iPhone simulator, I get New value: 1 New value: 5 New value: 10 New value: 15 If I tap the button, the app won't get a new value. I suppose that's because the subscription is cancelled at the end of viewDidLoad? If so, why does it get cancelled? I don't quite see a practical side of Combine's Subject. When is it useful? Thanks.

I have the following lines of code in practicing Combine. import UIKit import Combine class ViewController: UIViewController { // MARK: - Variables var cancellable: AnyCancellable? @Published var segmentNumber: Int = 0 // MARK: - IBOutlet @IBOutlet weak var actionButton: UIButton! // MARK: - IBAction @IBAction func segmentChanged(_ sender: UISegmentedControl) { segmentNumber = sender.selectedSegmentIndex } // MARK: - Life cycle override func viewDidLoad() { super.viewDidLoad() cancellable = $segmentNumber.receive(on: DispatchQueue.main) .assign(to: \.isEnabled, on: actionButton) } } I get an error at .assign that says Value of type 'UIView?' has no member 'isEnabled' What am I doing wrong? Thank you.

Hello. I'm a little bit confused about how TestFlight works. If I have an iOS app under development that has not been in the store and that has not been submitted for a review yet, can I use TestFlight to have it tested by my development team? I know that there are two types of tests, internal tests and external tests. It seems that you can use TestFlight for internal tests even if the app has not been submitted for a review. Thanks.