SwiftUI - Crash when presenting .sheet in minimal project that includes .toolbar - ios

I've run into a weird crash when presenting a sheet under certain conditions.I've been able to reproduce it in a starter project and have had confirmation from multiple people that it crashes on their end as well. The strange thing is, that for some simulators / users, these steps don't crash the app.
I've filed a Bug Report with Apple (FB9064549), but thought I'd ask it here as well.
The steps to reproduce the crash are as follows:
Click the "Open Detail View" button
Go back
Click the "Open Detail View" button again
Click the "Present Modal"
It will crash
The basic content view has a toolbar with a Menu (or just a normal Text) in it and a NavigationLink to push to a new page. If I comment out the .toolbar, the crash does not happen.
struct ContentView: View {
var body: some View {
NavigationView {
VStack {
NavigationLink(
destination: DetailView(),
label: {
Text("Open Detail View")
})
}
// If you comment this out, it does not crash
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
Menu {
ForEach(1...5, id: \.self) { index in
Button {
print("tap menu item")
} label: {
HStack {
Text("Menu Item \(index)")
}
}
}
} label: {
Text("Filter")
}
}
}
}
}
}
The presented DetailView can present a .sheet through a binding item. If I use the FullScreenCover instead, it does not crash.
struct DetailView: View {
#State var modalType: ModalType?
var body: some View {
Button(action: {
modalType = .modalWithTabView
}, label: {
Text("Present Modal")
})
.sheet(item: $modalType, content: { $0 })
}
}
enum ModalType: Identifiable, View {
case modalWithTabView
var id: String {
return "modalWithTabView"
}
var body: some View {
switch self {
case .modalWithTabView:
ModalWithTabView()
}
}
}
The sheet that is presented is a basic TabView pagination. If I don't add the PageTabViewStyle style, it does not crash.
struct ModalWithTabView: View {
#State var currentStep = 0
var body: some View {
TabView(selection: $currentStep) {
ForEach (0 ..< 10) { index in
Text("Page \(index)")
.tag(index)
}
}
// If you comment this out, it does not crash
.tabViewStyle(PageTabViewStyle())
}
}
If anyone has any pointers please let me know!

Related

SwiftUI - Navigation Link pops out on iPhone, but not in Simulator

I have an app that contains several views with NavigationLinks inside.
The main view looks like this, calling a Toolbar view I have created.
struct CountListView: View {
#StateObject var vm = CountListViewModel()
let navigationBar = HomePageNavigationBar()
var body: some View {
NavigationView {
List {
ForEach(vm.count, id: \.uid) { item in
NavigationLink(destination: CountView(count: item)) {
CountListItemView(name: item.name)
}
}
}
.toolbar {
navigationBar.rightSideOfBar()
navigationBar.leftSideOfBar()
}
.navigationBarTitle("Count")
The navigation bar function that is playing up looks like this
func leftSideOfBar() -> some ToolbarContent {
ToolbarItemGroup(placement: .navigationBarLeading) {
NavigationLink(destination: SettingsView()) {
Label("Settings", systemImage: "gear")
}
}
}
And the SettingsView is as follows:
struct SettingsView: View {
var body: some View {
List {
NavigationLink(destination: NameSettingView()) {
Text("Name")
}
.buttonStyle(PlainButtonStyle())
NavigationLink(destination: PrivacyPolicyView()) {
Text("Privacy Policy")
}
.buttonStyle(PlainButtonStyle())
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
When I open the Privacy Policy View on device, the returns to the SettingsView without any user intervention. But this problem doesn't exist in the simulator.

SwiftUI - NavigationLink cell in a Form stays highlighted after detail pop

In iOS 14, it appears that NavigationLinks do not become deselected after returning in a Form context.
This is also true for Form Pickers and anything else that causes the presentation of another View from a list (giving a highlight context to the presenting cell).
I didn't notice this behaviour in iOS 13.
Is there a way to 'deselect' the highlighted row once the other view is dismissed?
Example code:
struct ContentView: View {
var body: some View {
Form {
NavigationLink(destination: Text("Detail")) {
Text("Link")
}
}
}
}
(Different) Example visual:
In my case this behaviour appeared when using any Viewcontent (e.g. Text(), Image(), ...) between my NavigationView and List/Form.
var body: some View {
NavigationView {
VStack {
Text("This text DOES make problems.")
List {
NavigationLink(destination: Text("Doesn't work correct")) {
Text("Doesn't work correct")
}
}
}
}
}
Putting the Text() beneath the List does not make any problems:
var body: some View {
NavigationView {
VStack {
List {
NavigationLink(destination: Text("Does work correct")) {
Text("Does work correct")
}
}
Text("This text doesn't make problems.")
}
}
}
This is definitely a XCode 12 bug. As more people report this, as earlier it gets resolved.
I have also run into this issue and believed I found the root cause in my case.
In my case I had.a structure like the following:
struct Page1View: View {
var body: some View {
NavigationView {
List {
NavigationLink("Page 2", destination: Page2View())
}
.listStyle(GroupedListStyle())
.navigationBarTitle("Page 1")
}
}
}
struct Page2View: View {
var body: some View {
List {
NavigationLink("Page 3", destination: Text("Page 3"))
}
.listStyle(GroupedListStyle())
.navigationBarTitle("Page 2")
}
}
This issue would occur on the NavigationLink to Page 3. In the console output this error was showing when that link was used:
2021-02-13 16:41:00.599844+0000 App[59157:254215] [Assert] displayModeButtonItem is internally managed and not exposed for DoubleColumn style. Returning an empty, disconnected UIBarButtonItem to fulfill the non-null contract.
I discovered that I needed to apply .navigationViewStyle(StackNavigationViewStyle()) to the NavigationView and this solved the problem.
I.e.
struct Page1View: View {
var body: some View {
NavigationView {
List {
NavigationLink("Page 2", destination: Page2View())
}
.listStyle(GroupedListStyle())
.navigationBarTitle("Page 1")
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
Been fighting this issue half day today and came to this post that helped me to understand that issue appears if Text, Button or something else placed between NavigationView and in my case List. And I found solution that worked for me. Just add .zIndex() for the item. .zIndex() must be higher than for List Tried with Xcode 12.5.
var body: some View {
NavigationView {
VStack {
Text("This text DOES make problems.")
.zIndex(1.0)
List {
NavigationLink(destination: Text("Doesn't work correct")) {
Text("Doesn't work correct")
}
}
}
}
}
I did a bit more tinkering, it turns out this was caused due by having the UIHostingController being nested in a UINavigationController and using that navigation controller. Changing the navigation stack to use a SwiftUI NavigationView instead resolved this issue.
Similar to what #pawello2222 says in the question comments, I think the underlying cause is something to do with SwiftUI not understanding the proper navigation hierarchy when the external UINavigationController is used.
This is just one instance where this is fixed though, I'm still experiencing the issue in various other contexts depending on how my view is structured.
I've submitted an issue report FB8705430 to Apple, so hopefully this is fixed sometime soon.
Before (broken):
struct ContentView: View {
var body: some View {
Form {
NavigationLink(destination: Text("test")) {
Text("test")
}
}
}
}
// (UIKit presentation context)
let view = ContentView()
let host = UIHostingController(rootView: view)
let nav = UINavigationController(rootViewController: host)
present(nav, animated: true, completion: nil)
After (working):
struct ContentView: View {
var body: some View {
NavigationView {
Form {
NavigationLink(destination: Text("test")) {
Text("test")
}
}
}
}
}
// (UIKit presentation context)
let view = ContentView()
let host = UIHostingController(rootView: view)
present(host, animated: true, completion: nil)
This is definitely a bug in List, for now, my work-around is refreshing the List by changing the id, like this:
struct YourView: View {
#State private var selectedItem: String?
#State private var listViewId = UUID()
var body: some View {
List(items, id: \.id) {
NavigationLink(destination: Text($0.id),
tag: $0.id,
selection: $selectedItem) {
Text("Row \($0.id)")
}
}
.id(listViewId)
.onAppear {
if selectedItem != nil {
selectedItem = nil
listViewId = UUID()
}
}
}
}
I made a modifier based on this that you can use:
struct RefreshOnAppearModifier<Tag: Hashable>: ViewModifier {
#State private var viewId = UUID()
#Binding var selection: Tag?
func body(content: Content) -> some View {
content
.id(viewId)
.onAppear {
if selection != nil {
viewId = UUID()
selection = nil
}
}
}
}
extension View {
func refreshOnAppear<Tag: Hashable>(selection: Binding<Tag?>? = nil) -> some View {
modifier(RefreshOnAppearModifier(selection: selection ?? .constant(nil)))
}
}
use it like this:
List { ... }
.refreshOnAppear(selection: $selectedItem)
I managed to solve it by adding ids to the different components of the list, using binding and resetting the binding on .onDisappear
struct ContentView: View {
#State var selection: String? = nil
var body: some View {
NavigationView {
VStack {
Text("Hello, world!")
.padding()
List {
Section {
NavigationLink( destination: Text("Subscreen1"), tag: "link1", selection: $selection ) {
Text("Subscreen1")
}.onDisappear {
self.selection = nil
}
NavigationLink( destination: Text("Subscreen2"), tag: "link2", selection: $selection ) {
Text("Subscreen2")
}.onDisappear {
self.selection = nil
}
}.id("idSection1")
}
.id("idList")
}
}
}
}
I've also run into this issue and it seemed related to sheets as mentioned here.
My solution was to swizzle UITableView catch selections, and deselect the cell. The code for doing so is here. Hopefully this will be fixed in future iOS.
Adding .navigationViewStyle(StackNavigationViewStyle()) to NavigationView fixed it for me.
Suggested in this thread: https://developer.apple.com/forums/thread/660468
This is my solution to this issue.
// This in a stack in front of list, disables large navigation title from collapsing by disallowing list from scrolling on top of navigation title
public struct PreventCollapseView: View {
#State public var viewColor: Color?
public init(color: Color? = nil) {
self.viewColor = color
}
public var body: some View {
Rectangle()
.fill(viewColor ?? Color(UIColor(white: 0.0, alpha: 0.0005)))
.frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: 1)
}
}
// handy modifier..
extension List {
public func uncollapsing(_ viewUpdater: Bool) -> some View {
VStack(spacing: 0.0) {
Group {
PreventCollapseView()
self
}.id(viewUpdater)
}
}
}
struct TestView: View {
#State var updater: Bool = false
var body: some View {
List {
Text("Item one")
Text("Item two")
Text("Manually refresh")
.onTapGesture { DispatchQueue.main.async { updater.toggle() } }
.onAppear { print("List was refreshed") }
}
.uncollapsing(updater)
.clipped()
.onAppear { DispatchQueue.main.async { updater.toggle() }} // Manually refreshes list always when re-appearing/appearing
}
}
Add a NavigationView, configure for largeTitle, and embed TestView and it's all set. Toggle updater to refresh.
Having the same Problem. The weird thing is, that the exact same code worked in iOS13.
I'm having this issue with a simple list:
struct TestList: View {
let someArray = ["one", "two", "three", "four", "five"]
var body: some View {
List(someArray, id: \.self) { item in
NavigationLink(
destination: Text(item)) {
Text(item)
}.buttonStyle(PlainButtonStyle())
}.navigationBarTitle("testlist")
}
}
This is embedded in:
struct ListControllerView: View {
#State private var listPicker = 0
var body: some View {
NavigationView{
Group{
VStack{
Picker(selection: $listPicker, label: Text("Detailoverview")) {
Text("foo").tag(0)
Text("bar").tag(1)
Text("TestList").tag(2)
}
This is inside a Tabbar.
This is the workaround I've been using until this List issue gets fixed. Using the Introspect library, I save the List's UITableView.reloadData method and call it when it appears again.
import SwiftUI
import Introspect
struct MyView: View {
#State var reload: (() -> Void)? = nil
var body: some View {
NavigationView {
List {
NavigationLink("Next", destination: Text("Hello"))
}.introspectTableView { tv in
self.reload = tv.reloadData
}.onAppear {
self.reload?()
}
}
}
}

SwiftUI button inactive inside NavigationLink item area

I have a view for a list item that displays some news cards within a navigationLink.
I am supposed to add a like/unlike button within each news card of navigationLink, without being took to NavigationLink.destination page.
It seems like a small button inside a big button.
When you click that small one, execute the small one without executing the bigger one.
(note: the click area is covered by the two buttons, smaller one has the priority)
(In javascript, it seems like something called .stopPropaganda)
This is my code:
var body: some View {
NavigationView {
List {
ForEach(self.newsData.newsList, id:\.self) { articleID in
NavigationLink(destination: NewsDetail(articleID: articleID)) {
HStack {
Text(newsTitle)
Button(action: {
self.news.isBookmarked.toggle()
}) {
if self.news.isBookmarked {
Image(systemName: "bookmark.fill")
} else {
Image(systemName: "bookmark")
}
}
}
}
}
}
}
}
Currently, the button action (like/dislike) will not be performed as whenever the button is pressed, the navigationLink takes you to the destination view.
I have tried this almost same question but it cannot solve this problem.
Is there a way that makes this possible?
Thanks.
as of XCode 12.3, the magic is to add .buttonStyle(PlainButtonStyle()) or BorderlessButtonStyle to the button, when said button is on the same row as a NavigationLink within a List.
Without this particular incantation, the entire list row gets activated when the button is pressed and vice versa (button gets activated when NavigationLink is pressed).
This code does exactly what you want.
struct Artcle {
var text: String
var isBookmarked: Bool = false
}
struct ArticleDetail: View {
var article: Artcle
var body: some View {
Text(article.text)
}
}
struct ArticleCell: View {
var article: Artcle
var toggle: () -> ()
#State var showDetails = false
var body: some View {
HStack {
Text(article.text)
Spacer()
Button(action: {
self.toggle()
}) {
Image(systemName: article.isBookmarked ? "bookmark.fill" : "bookmark").padding()
}
.buttonStyle(BorderlessButtonStyle())
}
.overlay(
NavigationLink(destination: ArticleDetail(article: article), isActive: $showDetails) { EmptyView() }
)
.onTapGesture {
self.showDetails = true
}
}
}
struct ContentView: View {
#State var articles: [Artcle]
init() {
_articles = State(initialValue: (0...10).map { Artcle(text: "Article \($0 + 1)") })
}
func toggleArticle(at index: Int) {
articles[index].isBookmarked.toggle()
}
var body: some View {
NavigationView {
List {
ForEach(Array(self.articles.enumerated()), id:\.offset) { offset, article in
ArticleCell(article: article) {
self.toggleArticle(at: offset)
}
}
}
}
}
}

SwiftUI modal presentation works only once from navigationBarItems

Here is a bug in SwiftUI when you show modal from button inside navigation bar items.
In code below Button 1 works as expected, but Button 2 works only once:
struct DetailView: View {
#Binding var isPresented: Bool
#Environment (\.presentationMode) var presentationMode
var body: some View {
NavigationView {
Text("OK")
.navigationBarTitle("Details")
.navigationBarItems(trailing: Button(action: {
self.isPresented = false
// or:
// self.presentationMode.wrappedValue.dismiss()
}) {
Text("Done").bold()
})
}
}
}
struct ContentView: View {
#State var showSheetView = false
var body: some View {
NavigationView {
Group {
Text("Master")
Button(action: { self.showSheetView.toggle() }) {
Text("Button 1")
}
}
.navigationBarTitle("Main")
.navigationBarItems(trailing: Button(action: {
self.showSheetView.toggle()
}) {
Text("Button 2").bold()
})
}.sheet(isPresented: $showSheetView) {
DetailView(isPresented: self.$showSheetView)
}
}
}
This bug is from the middle of the last year, and it still in Xcode 11.3.1 + iOS 13.3 Simulator and iOS 13.3.1 iPhone XS.
Is here any workaround to make button work?
EDIT:
Seems to be tap area goes somewhere down and it's possible to tap below button to show modal.
Temporary solution to this is to use inline navigation bar mode:
.navigationBarTitle("Main", displayMode: .inline)
Well, the issue is in bad layout (seems broken constrains) of navigation bar button after sheet has closed
It is clearly visible in view hierarchy debug:
Here is a fix (workaround of course, but safe, because even after issue be fixed it will continue working). The idea is not to fight with broken layout but just create another button, so layout engine itself remove old-bad button and add new one refreshing layout. The instrument for this is pretty known - use .id()
So modified code:
struct ContentView: View {
#State var showSheetView = false
#State private var navigationButtonID = UUID()
var body: some View {
NavigationView {
Group {
Text("Master")
Button(action: { self.showSheetView.toggle() }) {
Text("Button 1")
}
}
.navigationBarTitle("Main")
.navigationBarItems(trailing: Button(action: {
self.showSheetView.toggle()
}) {
Text("Button 2").bold() // recommend .padding(.vertical) here
}
.id(self.navigationButtonID)) // force new instance creation
}
.sheet(isPresented: $showSheetView) {
DetailView(isPresented: self.$showSheetView)
.onDisappear {
// update button id after sheet got closed
self.navigationButtonID = UUID()
}
}
}
}

How to display missing back button in Master-Detail1-Detail2 view in SwiftUI in landscape?

I'm using a NavigationView and NavigationLinks to move from a MasterView to a Detail1View and then further to a Detail2View.
On an iPhone in portrait mode, the back button is displayed for all detail views and allows to move back from Detail2View to Detail1View, and then further to MasterView.
But on an iPhone in landscape mode or on an iPad, when moving from Detail1View to Detail2View, there is no back button. And it is thus impossible to go back to Detail1View.
Adding a 2nd NavigationView allows to have a back button, but it's not really a desirable workaround, as the 2nd UINavigationViewController is shown below the 1st one.
struct MyMasterView: View {
private let names = ["Homer", "Marge", "Bart", "Lisa"]
var body: some View {
List() {
Section(header: Text("The Simpsons")) {
ForEach(names, id: \.self) { name in
NavigationLink(destination: MyDetail1View(name: name)) {
Text(name)
}
}
}
}
.navigationBarTitle(Text("My App"))
}
}
struct MyDetail1View: View {
var name: String
var body: some View {
//NavigationView {
List {
NavigationLink(destination: MyDetail2View(name: name)) {
Text("Hello \(name)")
}
}
.navigationBarTitle(Text("Details 1"))
//}
}
}
struct MyDetail2View: View {
var name: String
var body: some View {
HStack {
Text("\(name), I'm sorry but in Landscape there is no back button...")
}
.navigationBarTitle(Text("Details 2"))
}
}
struct ContentView : View {
var body: some View {
NavigationView {
MyMasterView()
Text("In Landscape, swipe to start...")
}
}
}
The answer turns out to be as simple as using isDetailLink()!
NavigationLink(destination: MyDetail2View(name: name)) {
Text("Hello \(name)")
}.isDetailLink(false)
Credits to https://stackoverflow.com/a/57400873/2893408

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