Setting a navigationTitle is not working anymore on iOS 16 when having UINavigationController inside a TabView. Run the code with iOS 14/15, no issue there. If Tabview is commented, navigation title appears for iOS 16 too. It seems the problem is caused somehow by the TabView. I know I can send the title as a parameter but I would prefer not to, also, for the moment, switching to NavigationVies is not an option.
import SwiftUI
#main
struct CustomUIKitNavigationApp: App {
var body: some Scene {
WindowGroup {
TabView {
NavigationViewControllerRepresentable {
VStack {
Text("why navigation title is not working anymore on iOS 16 when in TabView?")
.navigationTitle("navigation is not appearing")
}
}
}
}
}
}
struct NavigationViewControllerRepresentable<Content: View>: UIViewControllerRepresentable {
let nav = UINavigationController()
init(#ViewBuilder content: #escaping () -> Content) {
let vc = HostingController(content: AnyView(content()))
nav.addChild(vc)
}
func makeUIViewController(context: Context) -> UINavigationController {
return nav
}
func updateUIViewController(_ pageViewController: UINavigationController, context: Context) {}
}
class HostingController: UIHostingController<AnyView> {
init(content: AnyView) {
super.init(rootView: AnyView(content))
}
#objc required dynamic init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) not implemented")
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
}
}
Related
I have a UIKit ViewController that's nested inside a SwiftUI view using ViewControllerRepresentable. The SwiftUI view manages a bit of state (an Int, in this example) that I want to display in the UIKit view. When the user taps a button in the SwiftUI parent view, the state change should be reflected in the UIKit view. I've tried using the #Binding property wrapper to keep the two in sync, but clearly I'm missing something, as my view controller's initialiser throws a compile-time error.
I'm quite new to iOS development so perhaps I'm going in the complete wrong direction here. Any help would be greatly appreciated.
The code is as follows (simplified):
struct ContentView: View {
#State private var currentNumber: Int
init(currentNumber: Int) {
self.currentNumber = currentNumber
}
var body: some View {
FancyLabelViewControllerRepresentable(currentNumber: self.$currentNumber)
Button("Increment") {
self.currentNumber += 1
}
}
}
struct FancyLabelViewControllerRepresentable: UIViewControllerRepresentable {
typealias UIViewControllerType = FancyLabelViewController
#Binding var currentNumber: Int
init(currentNumber: Binding<Int>) {
self._currentNumber = currentNumber
}
func makeUIViewController(context: Context) -> FancyLabelViewController {
let fancyLabel = FancyLabelViewController(number: self.currentNumber)
fancyLabel.currentNumberInLabel = self.currentNumber
return fancyLabel
}
func updateUIViewController(_ uiViewController: FancyLabelViewController, context: Context) {
uiViewController.currentNumberInLabel = self.currentNumber
}
}
class FancyLabelViewController: UIViewController {
var label = UILabel()
#Binding var currentNumberInLabel: Int
init(number: Int) {
// Error: 'self' used in property access 'currentNumberInLabel' before 'super.init' call
self.currentNumberInLabel = number
// Error: Property 'self.currentNumberInLabel' not initialized at super.init call
super.init(nibName: nil, bundle: nil)
}
required init(coder: NSCoder) {
fatalError("Not implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
label.text = "\(currentNumberInLabel)"
view = label
}
}
I think you don't need the
#Binding var currentNumberInLabel: Int
because the UIViewControllerRepresentable already takes care of updating the currentNumberInLabel value, but you also needs to update the
label.text = "\(currentNumberInLabel)"
So I did something like
class FancyLabelViewController: UIViewController {
var label = UILabel()
var currentNumberInLabel: Int
init(number: Int) {
self.currentNumberInLabel = number
super.init(nibName: nil, bundle: nil)
}
required init(coder: NSCoder) {
fatalError("Not implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
label.text = "\(currentNumberInLabel)"
view = label
}
func updateLabel() {
label.text = "\(currentNumberInLabel)"
}
}
and call updateLabel from UIViewControllerRepresentable as
func updateUIViewController(_ uiViewController: FancyLabelViewController, context: Context) {
uiViewController.currentNumberInLabel = self.currentNumber
uiViewController.updateLabel()
}
How can we add the Accessibility Identifier to NaviagationTitle Text. I know for buttons/text/Image/stack views we can use .accessibility(identifier: “some_identifier”).
struct SomeView: View {
var body: some View {
VStack {
Text("Title Text")
.accessibility(identifier: "title")
}
.navigationTitle("title") //How to add accessibilityIdentifier to Navigation bar title?
//.navigationTitle(Text("title").accessibility(identifier: "title"))
}
}
unable to add the modifier to .navigationBarTitle(Text(“title”), displayMode: .inline). Accessibility Identifiers are required for XCUI automation testing.
I don't think this is possible in SwiftUI using .accessibility(identifier:) - it might be worth submitting feedback to Apple.
However, you can still access the navigation bar by its identifier - just the default identifier is the text:
.navigationTitle("title")
let app = XCUIApplication()
app.launch()
assert(app.navigationBars["title"].exists) // true
Alternatively, you can try to access UINavigationBar using a helper extension (adapted from here):
struct NavigationBarAccessor: UIViewControllerRepresentable {
var callback: (UINavigationBar?) -> Void
private let proxyController = ViewController()
func makeUIViewController(context: UIViewControllerRepresentableContext<NavigationBarAccessor>) -> UIViewController {
proxyController.callback = callback
return proxyController
}
func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<NavigationBarAccessor>) {}
typealias UIViewControllerType = UIViewController
private class ViewController: UIViewController {
var callback: (UINavigationBar?) -> Void = { _ in }
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
callback(navigationController?.navigationBar)
}
}
}
Now you can access UINavigationBar from a SwiftUI view:
struct ContentView: View {
var body: some View {
NavigationView {
Text("text")
.navigationTitle("title")
.background(
NavigationBarAccessor {
$0?.accessibilityIdentifier = "id123"
}
)
}
}
}
Note that in the above example you set accessibilityIdentifier to the UINavigationBar itself and not to the title directly.
I have some code that causes SwiftUI previews to fail but will run successfully in the simulator and on a device. The SwiftUI previews failure diagnostics message is:
PreviewUpdateTimedOutError: Updating took more than 5 seconds
Updating a preview from ViewControllerPreviews in NestedTest.app (9218) took more than 5 seconds.
I have boiled the issue down to a minimal amount of code:
import SwiftUI
import UIKit
let createHostInInit = true
class ViewController: UIViewController {
private var host: TestViewHost? = nil
init() {
if createHostInInit {
host = TestViewHost()
}
super.init(nibName: nil, bundle: nil)
}
// Note: this is here to satisfy the compiler and to allow running this
// in the simulator as part of a default new project.
required init?(coder: NSCoder) {
if createHostInInit {
host = TestViewHost()
}
super.init(coder: coder)
}
override func viewDidLoad() {
super.viewDidLoad()
if !createHostInInit {
host = TestViewHost()
}
if let host = self.host {
addChild(host)
self.view.addSubview(host.view)
host.didMove(toParent: self)
host.view.frame = self.view.bounds
}
}
}
class TestViewHost: UIHostingController<TestView> {
init() {
super.init(rootView: TestView())
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
struct TestView: View {
var body: some View {
Text("Hi there!")
}
}
struct UIViewControllerPreviewer: UIViewControllerRepresentable {
let viewController: UIViewController
init(viewController: UIViewController) {
self.viewController = viewController
}
func makeUIViewController(context: Context) -> some UIViewController {
return viewController
}
func updateUIViewController(_ uiViewController: UIViewControllerType, context: Context) {
// Do nothing because this is only for previews
}
}
struct ViewControllerPreviews: PreviewProvider {
static var previews: some View {
return UIViewControllerPreviewer(viewController: ViewController())
}
}
If createHostInInit = true then the previews fail. If createHostInInit = false then the previews work. In either of these cases the UI looks correct in the simulator or on a device. So it would seem that something about the preview environment gets cranky about when a UIHostingController is created before viewDidLoad().
Did I miss some documentation for UIHostingController describing these limitations? Is this a bug?
This can be tested in Xcode by creating a new iOS single view project and dropping this code into ViewController.swift.
Thanks
I'm looking for a way to change the text color of the status bar that allows a different text color to be used for each view.
I've seen this Q&A, but it's not what I'm looking for. I'm not looking for solutions that only allow for one status bar text color for all views. I want to change the status bar text color for each view. For example, one view might have a dark background and so I need light text. I might navigate to another view with a light background, so now I need dark text. The suggested duplicate answer only returns .lightContent, which means that the status bar text color cannot change dynamically when I move to a different view.
This answer here works on my machine, but it's not performant. A comment under it corroborates this. The lag is unacceptable, so this solution is not good.
Other solutions I've seen so far cause this particular error:
Compiling failed: extensions of generic classes cannot contain '#objc' members
I've also tried using an Environment Object inside my Custom Controller:
import SwiftUI
/// Allows for the status bar colors to be changed from black to white on the dark gray title bar
class Controller<ContentView> : UIHostingController<ContentView> where ContentView : View {
#EnvironmentObject var statusBarTextColor: StatusBarTextColor
lazy var isDark: Bool = self.statusBarTextColor.isDark
override var preferredStatusBarStyle: UIStatusBarStyle {
return isDark ? .lightContent : .darkContent
}
}
This results in the error:
Thread 1: Fatal error: No ObservableObject of type StatusBarTextColor found. A View.environmentObject(_:) for StatusBarTextColor may be missing as an ancestor of this view.
Inside my SceneDelegate file, I do specify the StatusBarTextColor environmentObject:
window.rootViewController = Controller(
rootView: Home()
.environmentObject(PostData())
.environmentObject(CardPosition())
.environmentObject(StatusBarTextColor())
)
And this is the ObservableObject itself:
import Combine
import SwiftUI
final class StatusBarTextColor: ObservableObject {
#Published var isDark: Bool = true
}
If I were to guess why this doesn't work, I'd say it's because the Controller gets initialized before StatusBarTextColor is available.
The more I look into this problem, the more I think there isn't a solution. I've gone through just about every article, answer, and video on the subject. They all either use a Controller to only return .lightContent, or use storyboards and multiple controllers, which isn't what I'm using.
You can use the solution you found here, but instead of using onDisappear, which will have a delay for the color change until the view is completely gone, you can create a view modifier called onWillDisappear that exposes viewWillDisappear. The color change will happen as sooner.
Usage:
struct MyClass: View {
#Environment(\.localStatusBarStyle) var statusBarStyle
// ...
SomeView()
}.onAppear {
self.statusBarStyle.currentStyle = .darkContent
}
.onWillDisappear {
self.statusBarStyle.currentStyle = .lightContent
}
}
Code:
import SwiftUI
class HostingController<Content>: UIHostingController<Content> where Content: View {
private var internalStyle = UIStatusBarStyle.lightContent
#objc override dynamic open var preferredStatusBarStyle: UIStatusBarStyle {
get {
internalStyle
}
set {
internalStyle = newValue
self.setNeedsStatusBarAppearanceUpdate()
}
}
override init(rootView: Content) {
super.init(rootView:rootView)
LocalStatusBarStyleKey.defaultValue.getter = { self.preferredStatusBarStyle }
LocalStatusBarStyleKey.defaultValue.setter = { self.preferredStatusBarStyle = $0 }
}
#objc required dynamic init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
class LocalStatusBarStyle { // style proxy to be stored in Environment
fileprivate var getter: () -> UIStatusBarStyle = { .default }
fileprivate var setter: (UIStatusBarStyle) -> Void = {_ in}
var currentStyle: UIStatusBarStyle {
get { self.getter() }
set { self.setter(newValue) }
}
}
// Custom Environment key, as it is set once, it can be accessed from anywhere
// of SwiftUI view hierarchy
struct LocalStatusBarStyleKey: EnvironmentKey {
static let defaultValue: LocalStatusBarStyle = LocalStatusBarStyle()
}
extension EnvironmentValues { // Environment key path variable
var localStatusBarStyle: LocalStatusBarStyle {
get {
return self[LocalStatusBarStyleKey.self]
}
}
}
struct WillDisappearHandler: UIViewControllerRepresentable {
func makeCoordinator() -> WillDisappearHandler.Coordinator {
Coordinator(onWillDisappear: onWillDisappear)
}
let onWillDisappear: () -> Void
func makeUIViewController(context: UIViewControllerRepresentableContext<WillDisappearHandler>) -> UIViewController {
context.coordinator
}
func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<WillDisappearHandler>) {
}
typealias UIViewControllerType = UIViewController
class Coordinator: UIViewController {
let onWillDisappear: () -> Void
init(onWillDisappear: #escaping () -> Void) {
self.onWillDisappear = onWillDisappear
super.init(nibName: nil, bundle: nil)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
onWillDisappear()
}
}
}
struct WillDisappearModifier: ViewModifier {
let callback: () -> Void
func body(content: Content) -> some View {
content
.background(WillDisappearHandler(onWillDisappear: callback))
}
}
extension View {
func onWillDisappear(_ perform: #escaping () -> Void) -> some View {
self.modifier(WillDisappearModifier(callback: perform))
}
}
See original post with onWillDisappear code here
In your SceneDelegate you inject StatusBarTextColor() to the Home view. However, you declared the EvironmentObject in Controller.
The interactive pop gesture recognizer should allow the user to go back the the previous view in navigation stack when they swipe further than half the screen (or something around those lines). In SwiftUI the gesture doesn't get canceled when the swipe wasn't far enough.
SwiftUI: https://imgur.com/xxVnhY7
UIKit: https://imgur.com/f6WBUne
Question:
Is it possible to get the UIKit behaviour while using SwiftUI views?
Attempts
I tried to embed a UIHostingController inside a UINavigationController but that gives the exact same behaviour as NavigationView.
struct ContentView: View {
var body: some View {
UIKitNavigationView {
VStack {
NavigationLink(destination: Text("Detail")) {
Text("SwiftUI")
}
}.navigationBarTitle("SwiftUI", displayMode: .inline)
}.edgesIgnoringSafeArea(.top)
}
}
struct UIKitNavigationView<Content: View>: UIViewControllerRepresentable {
var content: () -> Content
init(#ViewBuilder content: #escaping () -> Content) {
self.content = content
}
func makeUIViewController(context: Context) -> UINavigationController {
let host = UIHostingController(rootView: content())
let nvc = UINavigationController(rootViewController: host)
return nvc
}
func updateUIViewController(_ uiViewController: UINavigationController, context: Context) {}
}
I ended up overriding the default NavigationView and NavigationLink to get the desired behaviour. This seems so simple that I must be overlooking something that the default SwiftUI views do?
NavigationView
I wrap a UINavigationController in a super simple UIViewControllerRepresentable that gives the UINavigationController to the SwiftUI content view as an environmentObject. This means the NavigationLink can later grab that as long as it's in the same navigation controller (presented view controllers don't receive the environmentObjects) which is exactly what we want.
Note: The NavigationView needs .edgesIgnoringSafeArea(.top) and I don't know how to set that in the struct itself yet. See example if your nvc cuts off at the top.
struct NavigationView<Content: View>: UIViewControllerRepresentable {
var content: () -> Content
init(#ViewBuilder content: #escaping () -> Content) {
self.content = content
}
func makeUIViewController(context: Context) -> UINavigationController {
let nvc = UINavigationController()
let host = UIHostingController(rootView: content().environmentObject(nvc))
nvc.viewControllers = [host]
return nvc
}
func updateUIViewController(_ uiViewController: UINavigationController, context: Context) {}
}
extension UINavigationController: ObservableObject {}
NavigationLink
I create a custom NavigationLink that accesses the environments UINavigationController to push a UIHostingController hosting the next view.
Note: I didn't implement the selection and isActive that the SwiftUI.NavigationLink has because I don't fully understand what they do yet. If you want to help with that please comment/edit.
struct NavigationLink<Destination: View, Label:View>: View {
var destination: Destination
var label: () -> Label
public init(destination: Destination, #ViewBuilder label: #escaping () -> Label) {
self.destination = destination
self.label = label
}
/// If this crashes, make sure you wrapped the NavigationLink in a NavigationView
#EnvironmentObject var nvc: UINavigationController
var body: some View {
Button(action: {
let rootView = self.destination.environmentObject(self.nvc)
let hosted = UIHostingController(rootView: rootView)
self.nvc.pushViewController(hosted, animated: true)
}, label: label)
}
}
This solves the back swipe not working correctly on SwiftUI and because I use the names NavigationView and NavigationLink my entire project switched to these immediately.
Example
In the example I show modal presentation too.
struct ContentView: View {
#State var isPresented = false
var body: some View {
NavigationView {
VStack(alignment: .center, spacing: 30) {
NavigationLink(destination: Text("Detail"), label: {
Text("Show detail")
})
Button(action: {
self.isPresented.toggle()
}, label: {
Text("Show modal")
})
}
.navigationBarTitle("SwiftUI")
}
.edgesIgnoringSafeArea(.top)
.sheet(isPresented: $isPresented) {
Modal()
}
}
}
struct Modal: View {
#Environment(\.presentationMode) var presentationMode
var body: some View {
NavigationView {
VStack(alignment: .center, spacing: 30) {
NavigationLink(destination: Text("Detail"), label: {
Text("Show detail")
})
Button(action: {
self.presentationMode.wrappedValue.dismiss()
}, label: {
Text("Dismiss modal")
})
}
.navigationBarTitle("Modal")
}
}
}
Edit: I started off with "This seems so simple that I must be overlooking something" and I think I found it. This doesn't seem to transfer EnvironmentObjects to the next view. I don't know how the default NavigationLink does that so for now I manually send objects on to the next view where I need them.
NavigationLink(destination: Text("Detail").environmentObject(objectToSendOnToTheNextView)) {
Text("Show detail")
}
Edit 2:
This exposes the navigation controller to all views inside NavigationView by doing #EnvironmentObject var nvc: UINavigationController. The way to fix this is making the environmentObject we use to manage navigation a fileprivate class. I fixed this in the gist: https://gist.github.com/Amzd/67bfd4b8e41ec3f179486e13e9892eeb
You can do this by descending into UIKit and using your own UINavigationController.
First create a SwipeNavigationController file:
import UIKit
import SwiftUI
final class SwipeNavigationController: UINavigationController {
// MARK: - Lifecycle
override init(rootViewController: UIViewController) {
super.init(rootViewController: rootViewController)
}
override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
delegate = self
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
delegate = self
}
override func viewDidLoad() {
super.viewDidLoad()
// This needs to be in here, not in init
interactivePopGestureRecognizer?.delegate = self
}
deinit {
delegate = nil
interactivePopGestureRecognizer?.delegate = nil
}
// MARK: - Overrides
override func pushViewController(_ viewController: UIViewController, animated: Bool) {
duringPushAnimation = true
super.pushViewController(viewController, animated: animated)
}
var duringPushAnimation = false
// MARK: - Custom Functions
func pushSwipeBackView<Content>(_ content: Content) where Content: View {
let hostingController = SwipeBackHostingController(rootView: content)
self.delegate = hostingController
self.pushViewController(hostingController, animated: true)
}
}
// MARK: - UINavigationControllerDelegate
extension SwipeNavigationController: UINavigationControllerDelegate {
func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
guard let swipeNavigationController = navigationController as? SwipeNavigationController else { return }
swipeNavigationController.duringPushAnimation = false
}
}
// MARK: - UIGestureRecognizerDelegate
extension SwipeNavigationController: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
guard gestureRecognizer == interactivePopGestureRecognizer else {
return true // default value
}
// Disable pop gesture in two situations:
// 1) when the pop animation is in progress
// 2) when user swipes quickly a couple of times and animations don't have time to be performed
let result = viewControllers.count > 1 && duringPushAnimation == false
return result
}
}
This is the same SwipeNavigationController provided here, with the addition of the pushSwipeBackView() function.
This function requires a SwipeBackHostingController which we define as
import SwiftUI
class SwipeBackHostingController<Content: View>: UIHostingController<Content>, UINavigationControllerDelegate {
func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
guard let swipeNavigationController = navigationController as? SwipeNavigationController else { return }
swipeNavigationController.duringPushAnimation = false
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
guard let swipeNavigationController = navigationController as? SwipeNavigationController else { return }
swipeNavigationController.delegate = nil
}
}
We then set up the app's SceneDelegate to use the SwipeNavigationController:
if let windowScene = scene as? UIWindowScene {
let window = UIWindow(windowScene: windowScene)
let hostingController = UIHostingController(rootView: ContentView())
window.rootViewController = SwipeNavigationController(rootViewController: hostingController)
self.window = window
window.makeKeyAndVisible()
}
Finally use it in your ContentView:
struct ContentView: View {
func navController() -> SwipeNavigationController {
return UIApplication.shared.windows[0].rootViewController! as! SwipeNavigationController
}
var body: some View {
VStack {
Text("SwiftUI")
.onTapGesture {
self.navController().pushSwipeBackView(Text("Detail"))
}
}.onAppear {
self.navController().navigationBar.topItem?.title = "Swift UI"
}.edgesIgnoringSafeArea(.top)
}
}