Standard Menu Setup with iOS16 - swiftui

It isn't very clear how Apple wants us to create a standard menu in the new navigation logic released with iOS 16. Some of the online examples that I have seen use the same called logic to handle all their menu items. In the logic below I have created a three item menu, but I don't see a decent method of calling the associated logic for each subview (since each has a different name). I want to call Apples and Tomatoes as well as Grapes when selected from the menu.
struct ContentView: View {
let menus: [Menu] = [
.init(name: "Buy Grapes"),
.init(name: "Buy Apples"),
.init(name: "Buy Tomatoes"),
]
var body: some View {
NavigationStack {
VStack {
List (menus) { singMenu in
NavigationLink(singMenu.name, value: singMenu)
}
.navigationDestination(for: Menu.self) { singMenu in
// call page logic here
Grapes()
.navigationTitle(singMenu.name)
.navigationBarTitleDisplayMode(.inline)
}
}
}
}
}
struct Menu: Identifiable, Hashable {
var id = UUID()
let name: String
}
struct Grapes: View {
var body: some View {
Text("View Grapes here")
}
}
struct Apples: View {
var body: some View {
Text("View Apples here")
}
}
struct Tomatoes: View {
var body: some View {
Text("View Tomatoes here")
}
}

Related

The searchable modifier on tvOS, when inside a NavigationView, doesn't allow refocusing the search bar

When using a NavigationView and a ScrollView with searchable, as soon as you focus a item in the LazyVGrid the search bar collapses the keyboard, and it's no longer possible to re-focus the search bar to change the query.
It doesn't matter if the .searchable modifier is applied to the ScrollView or the NavigationView.
The more I look at it, the more it appears to be a SwiftUI bug on tvOS, but I would still like to find a workaround, if possible.
Sample code which reproduces the problem:
import SwiftUI
struct ContentView: View {
private var fruits = ["Apples", "Pears", "Oranges", "Plums", "Pineapples", "Bananas"]
#State private var items: [String]
#State private var searchText: String = ""
init() {
self.items = fruits
}
var body: some View {
NavigationView {
ScrollView {
LazyVGrid(columns: [GridItem(.adaptive(minimum: 300))], spacing: 40) {
ForEach(items, id: \.self) { item in
NavigationLink(destination: DetailView(text: item)) {
Text(item)
}
}
}
}
.searchable(text: $searchText)
.onChange(of: searchText) { query in
if query.isEmpty {
items = fruits
} else {
items = fruits.filter { $0.contains(query) }
}
}
}
}
}
struct DetailView: View {
let text: String
var body: some View {
Text(text)
}
}
Gif illustrating the problem:

SwiftUI selection in lists not working on reused cells

Consider the following project with two views. The first view presents the second one:
import SwiftUI
struct ContentView: View {
private let data = 0...1000
#State private var selection: Set<Int> = []
#State private var shouldShowSheet = false
var body: some View {
self.showSheet()
//self.showPush()
}
private func showSheet() -> some View {
Button(action: {
self.shouldShowSheet = true
}, label: {
Text("Selected: \(selection.count) items")
}).sheet(isPresented: self.$shouldShowSheet) {
EditFormView(selection: self.$selection)
}
}
private func showPush() -> some View {
NavigationView {
Button(action: {
self.shouldShowSheet = true
}, label: {
NavigationLink(destination: EditFormView(selection: self.$selection),
isActive: self.$shouldShowSheet,
label: {
Text("Selected: \(selection.count) items")
})
})
}
}
}
struct EditFormView: View {
private let data = 0...1000
#Binding var selection: Set<Int>
#State private var editMode: EditMode = .active
init(selection: Binding<Set<Int>>) {
self._selection = selection
}
var body: some View {
List(selection: self.$selection) {
ForEach(data, id: \.self) { value in
Text("\(value)")
}
}.environment(\.editMode, self.$editMode)
}
}
Steps to reproduce:
Create an app with the above two views
Run the app and present the sheet with the editable list
Select some items at random indexes, for example a handful at index 0-10 and another handful at index 90-100
Close the sheet by swiping down/tapping back button
Open the sheet again
Scroll to indexes 90-100 to view the selection in the reused cells
Expected:
The selected indexes as you had will be in “selected state”
Actual:
The selection you had before is not marked as selected in the UI, even though the binding passed to List contains those indexes.
This occurs both on the “sheet” presentation and the “navigation link” presentation.
If you select an item in the list, the “redraw” causes the original items that were originally not shown as selected to now be shown as selected.
Is there a way around this?
It looks like EditMode bug, worth submitting feedback to Apple. The possible solution is to use custom selection feature.
Here is a demo of approach (modified only part). Tested & worked with Xcode 11.4 / iOS 13.4
struct EditFormView: View {
private let data = 0...1000
#Binding var selection: Set<Int>
init(selection: Binding<Set<Int>>) {
self._selection = selection
}
var body: some View {
List(selection: self.$selection) {
ForEach(data, id: \.self) { value in
self.cell(for: value)
}
}
}
// also below can be separated into standalone view
private func cell(for value: Int) -> some View {
let selected = self.selection.contains(value)
return HStack {
Image(systemName: selected ? "checkmark.circle" : "circle")
.foregroundColor(selected ? Color.blue : nil)
.font(.system(size: 24))
.onTapGesture {
if selected {
self.selection.remove(value)
} else {
self.selection.insert(value)
}
}.padding(.trailing, 8)
Text("\(value)")
}
}
}

SwiftUI: MasterDetailView within in Tabbed View loses "State"

I have a MasterDetailView within a Tabbed View. If the user tabs the MasterDetailView and selects an entry in the master view, the detail is presented in the detail view. After selecting another tab and switching back to the MasterDetailView, the detail is no longer selected - the MasterDetailView completely loses its state like is is completely rendered.
private let dateFormatter: DateFormatter = {
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
dateFormatter.timeStyle = .medium
return dateFormatter
}()
struct MasterDetailView: View {
#State private var dates = [Date]()
var body: some View {
NavigationView {
MasterView(dates: $dates)
.navigationBarTitle(Text("Master"))
.navigationBarItems(
leading: EditButton(),
trailing: Button(
action: {
withAnimation { self.dates.insert(Date(), at: 0) }
}
) {
Image(systemName: "plus")
}
)
DetailView()
}.navigationViewStyle(DoubleColumnNavigationViewStyle())
}
}
struct MasterView: View {
#Binding var dates: [Date]
var body: some View {
List {
ForEach(dates, id: \.self) { date in
NavigationLink(
destination: DetailView(selectedDate: date)
) {
Text("\(date, formatter: dateFormatter)")
}
}.onDelete { indices in
indices.forEach { self.dates.remove(at: $0) }
}
}
}
}
struct DetailView: View {
var selectedDate: Date?
var body: some View {
Group {
if selectedDate != nil {
Text("\(selectedDate!, formatter: dateFormatter)")
} else {
Text("Detail view content goes here")
}
}.navigationBarTitle(Text("Detail"))
}
}
struct ContentView: View {
#State private var selection = 0
var body: some View {
TabView(selection: $selection){
Text("First View")
.font(.title)
.tabItem {
VStack {
Image("first")
Text("First")
}
}
.tag(0)
MasterDetailView()
.tabItem {
VStack {
Image("second")
Text("Master Detail")
}
}
.tag(1)
}
}
}
Is there a way to "reuse" the MasterDetailView when the user selects that tab?
I know I can use #State and #Binding to save and restore the state (like the selected entry in the master view) and in that simple example that might be a solution. But in a complex app - for example when the MasterDetailView includes a deep view hierarchy - it's not useful to manage (save and restore) the complete state of a view.
Variations on this question have been asked several times, and so far, the consensus is that SwiftUI does not support this use case yet. I'm sure it's on their radar, but the more people who ask for this feature, the more likely it will be prioritized for next year's updates.
Here's an answer where someone got the behavior you're wanting by wrapping UITabBarController for use with SwiftUI.

How to edit an item in a list using NavigationLink?

I am looking for some guidance with SwiftUI please.
I have a view showing a simple list with each row displaying a "name" string. You can add items to the array/list by clicking on the trailing navigation bar button. This works fine. I would now like to use NavigationLink to present a new "DetailView" in which I can edit the row's "name" string. I'm struggling with how to use a binding in the detailview to update the name.
I've found plenty of tutorials online on how to present data in the new view, but nothing on how to edit the data.
Thanks in advance.
ContentView:
struct ListItem: Identifiable {
let id = UUID()
let name: String
}
class MyListClass: ObservableObject {
#Published var items = [ListItem]()
}
struct ContentView: View {
#ObservedObject var myList = MyListClass()
var body: some View {
NavigationView {
List {
ForEach(myList.items) { item in
NavigationLink(destination: DetailView(item: item)) {
Text(item.name)
}
}
}
.navigationBarItems(trailing:
Button(action: {
let item = ListItem(name: "Test")
self.myList.items.append(item)
}) {
Image(systemName: "plus")
}
)
}
}
}
DetailView
struct DetailView: View {
var item: ListItem
var body: some View {
TextField("", text: item.name)
}
}
The main idea that you pass in DetailsView not item, which is copied, because it is a value, but binding to the corresponding item in your view model.
Here is a demo with your code snapshot modified to fulfil the requested behavior:
struct ListItem: Identifiable, Equatable {
var id = UUID()
var name: String
}
class MyListClass: ObservableObject {
#Published var items = [ListItem]()
}
struct ContentView: View {
#ObservedObject var myList = MyListClass()
var body: some View {
NavigationView {
List {
ForEach(myList.items) { item in
// Pass binding to item into DetailsView
NavigationLink(destination: DetailView(item: self.$myList.items[self.myList.items.firstIndex(of: item)!])) {
Text(item.name)
}
}
}
.navigationBarItems(trailing:
Button(action: {
let item = ListItem(name: "Test")
self.myList.items.append(item)
}) {
Image(systemName: "plus")
}
)
}
}
}
struct DetailView: View {
#Binding var item: ListItem
var body: some View {
TextField("", text: self.$item.name)
}
}

Show a new View from Button press Swift UI

I would like to be able to show a new view when a button is pressed on one of my views.
From the tutorials I have looked at and other answered questions here it seems like everyone is using navigation button within a navigation view, unless im mistaken navigation view is the one that gives me a menu bar right arrows the top of my app so I don't want that. when I put the navigation button in my view that wasn't a child of NavigationView it was just disabled on the UI and I couldn't click it, so I guess I cant use that.
The other examples I have seen seem to use presentation links / buttons which seem to show a sort of pop over view.
Im just looking for how to click a regular button and show another a view full screen just like performing a segue used to in the old way of doing things.
Possible solutions
1.if you want to present on top of current view(ex: presentation style in UIKit)
struct ContentView: View {
#State var showingDetail = false
var body: some View {
Button(action: {
self.showingDetail.toggle()
}) {
Text("Show Detail")
}.sheet(isPresented: $showingDetail) {
DetailView()
}
}
}
2.if you want to reset current window scene stack(ex:after login show home screen)
Button(action: goHome) {
HStack(alignment: .center) {
Spacer()
Text("Login").foregroundColor(Color.white).bold()
Spacer()
}
}
func goHome() {
if let window = UIApplication.shared.windows.first {
window.rootViewController = UIHostingController(rootView: HomeScreen())
window.makeKeyAndVisible()
}
}
3.push new view (ex: list->detail, navigation controller of UIKit)
struct ContentView: View {
var body: some View {
NavigationView {
VStack {
NavigationLink(destination: DetailView()) {
Text("Show Detail View")
}.navigationBarTitle("Navigation")
}
}
}
}
4.update the current view based on #state property, (ex:show error message on login failure)
struct ContentView: View {
#State var error = true
var body: some View {
...
... //login email
.. //login password
if error {
Text("Failed to login")
}
}
}
For simple example you can use something like below
import SwiftUI
struct ExampleFlag : View {
#State var flag = true
var body: some View {
ZStack {
if flag {
ExampleView().tapAction {
self.flag.toggle()
}
} else {
OtherExampleView().tapAction {
self.flag.toggle()
}
}
}
}
}
struct ExampleView: View {
var body: some View {
Text("some text")
}
}
struct OtherExampleView: View {
var body: some View {
Text("other text")
}
}
but if you want to present more view this way looks nasty
You can use stack to control view state without NavigationView
For Example:
class NavigationStack: BindableObject {
let didChange = PassthroughSubject<Void, Never>()
var list: [AuthState] = []
public func push(state: AuthState) {
list.append(state)
didChange.send()
}
public func pop() {
list.removeLast()
didChange.send()
}
}
enum AuthState {
case mainScreenState
case userNameScreen
case logginScreen
case emailScreen
case passwordScreen
}
struct NavigationRoot : View {
#EnvironmentObject var state: NavigationStack
#State private var aligment = Alignment.leading
fileprivate func CurrentView() -> some View {
switch state.list.last {
case .mainScreenState:
return AnyView(GalleryState())
case .none:
return AnyView(LoginScreen().environmentObject(state))
default:
return AnyView(AuthenticationView().environmentObject(state))
}
}
var body: some View {
GeometryReader { geometry in
self.CurrentView()
.background(Image("background")
.animation(.fluidSpring())
.edgesIgnoringSafeArea(.all)
.frame(width: geometry.size.width, height: geometry.size.height,
alignment: self.aligment))
.edgesIgnoringSafeArea(.all)
.onAppear {
withAnimation() {
switch self.state.list.last {
case .none:
self.aligment = Alignment.leading
case .passwordScreen:
self.aligment = Alignment.trailing
default:
self.aligment = Alignment.center
}
}
}
}
.background(Color.black)
}
}
struct ExampleOfAddingNewView: View {
#EnvironmentObject var state: NavigationStack
var body: some View {
VStack {
Button(action:{ self.state.push(state: .emailScreen) }){
Text("Tap me")
}
}
}
}
struct ExampleOfRemovingView: View {
#EnvironmentObject var state: NavigationStack
var body: some View {
VStack {
Button(action:{ self.state.pop() }){
Text("Tap me")
}
}
}
}
In my opinion this bad way, but navigation in SwiftUI much worse