first question on StackOverflow (and relatively new to native app dev targeting macOS).
I'm currently trying to build a simple SwiftUI view, that leverages WKWebView's loadHTMLString function, to display hardcoded HTML string on the screen.
AFAIK webkit does not support SwiftUI as of the moment, so I need to embed AppKit UI in my SwiftUI app using NSViewRepresentable. This what I got so far following the docs and XCode's autocomplete:
import SwiftUI
import WebKit
struct HTMLView: NSViewRepresentable {
typealias NSViewType = WKWebView
let html = "<h1>Hello wordl</h1>"
func makeNSView(context: Context) -> WKWebView {
let webview = WKWebView()
return webview
}
func updateNSView(_ nsView: WKWebView, context: Context) {
nsView.loadHTMLString(html, baseURL: nil)
}
}
struct HTMLView_Previews: PreviewProvider {
static var previews: some View {
HTMLView()
}
}
Should be noted that preview canvas does not load the HTML (displays empty window).
I then replace the default Text() view in ContentView.Swift with HTMLView(), and run my application.
The application compiles, but the WebView fails to load the HTML (I get an empty window). I get the following errors in console:
WebPageProxy::processDidTerminate: (pid 0), reason 3
WebPageProxy::dispatchProcessDidTerminate: reason = 3
WebPageProxy::processDidTerminate: (pid 0), reason 3
WebPageProxy::dispatchProcessDidTerminate: reason = 3
WebPageProxy::tryReloadAfterProcessTermination: process crashed and the client did not handle it, not reloading the page because we reached the maximum number of attempts
Any help with the above would be highly appreciated!
On macOS, although it doesn't seem like this should be necessary, you need to set "Outgoing Connections (Client)" to true in your "Signing and Capabilities" on your target in order for WKWebView to load, even though you're loading from a string and not from an external page.
As soon as I changed this, your example worked fine.
Related
I have a SwiftUI app that shows a GKGameCenterViewController. I am hitting a problem which is specific to iPads running iPadOS 16.1 and above in light mode only. Under these circumstances, the child views of GKGameCenterViewController appear as black text on a dark background, which is very difficult to read - see screenshot for the leaderboard "Test" below.
The app runs with versions of iOS/iPadOS 14.0 and above. The problem is very specific to iPads running iPadOS 16.1 and above in light mode. The top-level parent view of GKGameCenterViewController (showing the title "Game Center" and a navigation menu) works fine, only the child views are affected. The problem is not seen on iPhones, nor on iPads running versions of iPadOS 14 or 15. The problem is also not seen on iPads running iPadOS 16.1 and above if dark mode is in operation when GKGameCenterViewController is first shown.
The GKGameCenterViewController is being presented using a UIViewControllerRepresentable as a layer in a ZStack. From the examples I could find, using UIViewControllerRepresentable seems to be the standard way to do it, as also described in How to display Game Center leaderboard with SwiftUI.
It is interesting to note that the problem is not seen when the Game Center dashboard is shown by tapping the Game Center access point. I assume that the access point shows the GKGameCenterViewController in a different way.
The following stripped-down code illustrates how the GKGameCenterViewController is being shown. This is a standalone app that can be used to reproduce the problem. However, for Game Center authentication to work and for the overview of leaderboards to show, the following needs to be done too:
in Xcode, Game Center needs to be added as a capability to the app target
the app needs to be added to App Store Connect
Game Center needs to be enabled for the app version in App Store Connect
a leaderboard needs to be added.
import SwiftUI
import GameKit
#main
struct GameCenterBlackoutApp: App {
var body: some Scene {
WindowGroup {
MyContentView()
}
}
}
struct MyContentView: View {
#State private var showingGameCenter = false
var body: some View {
ZStack {
Button("Show Game Center leaderboards") {
showingGameCenter = true
}
if showingGameCenter {
MyGameCenterView(showingGameCenter: $showingGameCenter)
.ignoresSafeArea()
}
}
.onAppear {
// Authenticate the local player
GKLocalPlayer.local.authenticateHandler = handleAuthenticationOutcome
}
}
private func handleAuthenticationOutcome(vc: UIViewController?, error: Error?) {
if let error {
#if DEBUG
print("Failed to authenticate player: \(error)")
#endif
}
// Prepare and show the GameCenter access point.
// If authentication failed then the access point takes
// the form of a button to sign in
GKAccessPoint.shared.location = .topTrailing
GKAccessPoint.shared.showHighlights = false
GKAccessPoint.shared.isActive = true
}
}
/// A Bridge between the Game Center view controller and its wrapper
final class MyCoordinator : NSObject, GKGameCenterControllerDelegate {
#Binding private var showingGameCenter: Bool
init(showingGameCenter: Binding<Bool>) {
self._showingGameCenter = showingGameCenter
}
func gameCenterViewControllerDidFinish(
_ gameCenterViewController: GKGameCenterViewController
) {
gameCenterViewController.dismiss(animated:false)
showingGameCenter = false
}
}
/// A wrapper for GKGameCenterViewController
struct MyGameCenterView: UIViewControllerRepresentable {
typealias Coordinator = MyCoordinator
/// Binding to the state variable that controls the visibility of the Game Center layer
#Binding private var showingGameCenter: Bool
init(showingGameCenter: Binding<Bool>) {
self._showingGameCenter = showingGameCenter
}
/// Factory function for the Bridge between the GKGameCenterViewController and this wrapper view
func makeCoordinator() -> Coordinator {
MyCoordinator(showingGameCenter: $showingGameCenter)
}
/// Creates the GKGameCenterViewController
func makeUIViewController(
context: UIViewControllerRepresentableContext<MyGameCenterView>
) -> GKGameCenterViewController {
let result = GKGameCenterViewController(state: .leaderboards)
result.gameCenterDelegate = context.coordinator
return result
}
/// Stub implementation of protocol method
func updateUIViewController(
_ gameCenterViewController: GKGameCenterViewController,
context: UIViewControllerRepresentableContext<MyGameCenterView>
) {
// NOP
}
}
I would be really grateful for any workaround that will resolve the black text issue as described and allow the child views of GKGameCenterViewController to be shown in a normal, readable foreground color. I have tried all of the following, none of which made any difference:
setting .dark or .light as .overrideUserInterfaceStyle on the view controller
applying .environment(\.colorScheme, .dark) to the UIViewControllerRepresentable or to a higher-level parent
applying .dark or .white as .preferredColorScheme on the UIViewControllerRepresentable
using modifier .toolbarColorScheme(all combinations of parameters) on the UIViewControllerRepresentable
applying Color.white as .foregroundColor on the UIViewControllerRepresentable
using black or white background behind the UIViewControllerRepresentable
showing the UIViewControllerRepresentable as an overlay instead of as a ZStack layer
not enabling the Game Center access point
using other GKGameCenterViewControllerState values in the init call
using other init functions for GKGameCenterViewController
using deprecated init functions and setters on GKGameCenterViewController.
BTW, I also reported the issue to Apple, but they have not been able to help.
I have an Xcode 14.1 project that has a target with two destinations: "iPad" and "Mac (Designed for iPad)".
The code shown in this question is simplified from the actual project to illustrate the problem.
Since SwiftUI does not directly support PDFView directly the app has a PDFView wrapped in UIViewRepresentable:
import PDFKit
import SwiftUI
struct MyPDFView: UIViewRepresentable {
func makeUIView(context: Context) -> UIView {
let path = Bundle.main.path(forResource: "basic-link-1", ofType: "pdf")!
let pdfDocument = PDFDocument(url: URL(filePath: path))
let pdfView = PDFView()
pdfView.document = pdfDocument
pdfView.autoScales = true
return pdfView
}
func updateUIView(_ uiView: UIView, context: Context) {
}
}
("basic-link-1.pdf" is a simple PDF file that I got from an Adobe tutorial. It is a one-page document with various Link annotations.)
The PDFView is shown in the app's main view:
import SwiftUI
struct ContentView: View {
var body: some View {
MyPDFView()
}
}
When I run the app on an iPad or iPad simulator, the Link annotations in "basic-link-1.pdf" work. Tapping on one of them takes the user to another page in the document or opens a web page (depending on the exact type of link in the Link annotation).
When I run the same app directly on Mac in "Mac (Designed for iPad)" mode, nothing happens when I click on the links in the PDF view. Does anyone know what is different about this mode or what I have to do differently to get the links to react to clicks?
Additional info: I don't show it in my sample code here, but if I register a PDFViewDelegate for MyPDFView, its pdfViewWillClick(onLink:sender:url) callback gets called if the app is running on an iPad, but does not get called if the app is running in "Mac (Designed for iPad)" mode.
Also, all development and testing above was done on a MacBook Air M2.
I have a simple widget (medium-sized) with two texts, and what I want is to be able to perform a deep link to lead the user to a specific section of my app, but I can't seem to find a way to do so.
The view I have written (which is very simple):
HStack {
Text("FIRST ITEM")
Spacer()
Text("SECOND ITEM")
}
I have already tried to replace
Text("SECOND ITEM")
with
Link("SECOND ITEM destination: URL(string: myDeeplinkUrl)!)
but it doesn't work either.
In the Widget view you need to create a Link and set its destination url:
struct SimpleWidgetEntryView: View {
var entry: SimpleProvider.Entry
var body: some View {
Link(destination: URL(string: "widget://link1")!) {
Text("Link 1")
}
}
}
Note that Link works in medium and large Widgets only. If you use a small Widget you need to use:
.widgetURL(URL(string: "widget://link0")!)
In your App view receive the url using onOpenURL:
#main
struct WidgetTestApp: App {
var body: some Scene {
WindowGroup {
Text("Test")
.onOpenURL { url in
print("Received deep link: \(url)")
}
}
}
}
It is also possible to receive deep links in the SceneDelegate by overriding:
func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>)
You can find more explanation on how to use this function in this thread:
Detect app launch from WidgetKit widget extension
Here is a GitHub repository with different Widget examples including the DeepLink Widget.
Also, you can do it using AppDelegate (if you not using SceneDelegate):
.widgetURL(URL(string: "urlsceheme://foobarmessage"))
// OR
Link(destination: URL(string: "urlsceheme://foobarmessage")!) {
Text("Foo")
}
Set this code within AppDelegate
func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
let message = url.host?.removingPercentEncoding // foobarmessage
return true
}
See docs on: Respond to User Interactions
When users interact with your widget, the system launches your app to handle the request. When the system activates your app, navigate to the details that correspond to the widget’s content. Your widget can specify a URL to inform the app what content to display. To configure custom URLs in your widget:
For all widgets, add the widgetURL(_:) view modifier to a view in your widget’s view hierarchy. If the widget’s view hierarchy includes more than one widgetURL modifier, the behavior is undefined.
For widgets that use WidgetFamily.systemMedium or WidgetFamily.systemLarge, add one or more Link controls to your widget’s view hierarchy. You can use both widgetURL and Link controls. If the interaction targets a Link control, the system uses the URL in that control. For interactions anywhere else in the widget, the system uses the URL specified in the widgetURL view modifier.
For example, a widget that displays details of a single character in a game can use widgetURL to open the app to that character’s detail.
#ViewBuilder
var body: some View {
ZStack {
AvatarView(entry.character)
.widgetURL(entry.character.url)
.foregroundColor(.white)
}
.background(Color.gameBackground)
}
If the widget displays a list of characters, each item in the list can be in a Link control. Each Link control specifies the URL for the specific character it displays.
When the widget receives an interaction, the system activates the containing app and passes the URL to onOpenURL(perform:), application(_:open:options:), or application(_:open:), depending on the life cycle your app uses.
If the widget doesn’t use widgetURL or Link controls, the system activates the containing app and passes an NSUserActivity to onContinueUserActivity(_:perform:), application(_:continue:restorationHandler:), or application(_:continue:restorationHandler:). The user activity’s userInfo dictionary contains details about the widget the user interacted with. Use the keys in WidgetCenter.UserInfoKey to access these values from Swift code. To access the userInfo values from Objective-C, use the keys WGWidgetUserInfoKeyKind and WGWidgetUserInfoKeyFamily instead.
I’m having trouble using an arrow key as a .keyboardShortcut in SwiftUI. Sample iOS app:
struct ContentView: View {
#State var time: Date = Date()
var body: some View {
VStack {
Button("Press Me") {
time = Date()
}
.keyboardShortcut(KeyEquivalent.rightArrow, modifiers: [])
Text("\(time)")
}
}
}
This puts up a button that, when pressed, changes the time displayed in the text. I should be able to use the right arrow key on the keyboard and get it to work as well, but it doesn’t. If I change the keyboardShortcut line to, say, this:
.keyboardShortcut(KeyEquivalent(“a”), modifiers: [])
everything works as expected. You can press the “a” key and the time changes. If you hold down the command key, you get the system-provided HUD that shows the “a" shortcut. Change it to .rightAarrow and it shows the HUD but there’s an enclosed “?” for the shortcut, and the shortcut doesn’t fire when the arrow key is pressed.
(I’m aware I could do this using UIKit. Trying to understand why the SwiftUI version doesn’t work.)
I am attempting to accomplish the same objective in my MacOS SwiftUI app. Using your code as an example, I inserted the .keyboardShortcut(KeyEquivalent.rightArrow, modifiers: []) after my Button{} and it works fine. I then pasted your entire code into my ContentView and again it works fine. I do not know why it works in my MacOS app but not in your iOS app.
Copying my answer from this post. I wasn't able to use SwiftUI's commands to get this to work on iOS/iPadOS. However I found some luck using view controllers, and if you're using SwiftUI views then this will work with a hosting controller.
In your view controller, add the code below. The important bit is setting wantsPriorityOverSystemBehavior to true:
override var keyCommands: [UIKeyCommand]? {
let upArrow = UIKeyCommand(input: UIKeyCommand.inputUpArrow, modifierFlags: [], action: #selector(test))
upArrow.wantsPriorityOverSystemBehavior = true
return [upArrow]
}
#objc func test(_ sender: UIKeyCommand) {
print(">>> test was pressed")
}
I'm trying to execute some code I'd have previously put in my app delegate, such as saving my managed object context when entering the background. I put the call in the .onChange for the scenePhase, but I'm not getting anything. Here's a sample project:
import SwiftUI
#main
struct PhaseApp: App {
#Environment(\.scenePhase) private var scenePhase
var body: some Scene {
WindowGroup {
Text("Hello, world.")
}
.onChange(of: scenePhase) { phase in
switch phase {
case .active:
print("Active")
case .background:
print("Background")
case .inactive:
print("Inactive")
#unknown default: break
}
}
}
}
I'd expect to get a print command in the Simulator or on my test device whenever I press Home or tap the app, but nothing happens.
I acknowledge this question is specifically about schenePhase changes, however, on macOS I am not able to receive any .background notifications when a user switches to a different app. The older NotificationCenter strategy works as I expected, on both platforms. I'll add this to the mix for anyone who is just trying to execute some code, onForeground / onBackground on iOS and macOS.
On any view, you can attach:
.onReceive(NotificationCenter.default.publisher(for: .willResignActiveNotification)) { _ in
doBackgroundThing()
}
The events you may care about are:
iOS: willResignActiveNotification & willEnterForegroundNotification
macOS: willResignActiveNotification & willBecomeActiveNotification
You can find all NotificationCenter Names here.
I use will* variants for background because I assume they'll be called early in the process, and I use did* variants for foreground, because they are called regardless of whether the app is launched for the first time, or it's coming out of background.
I use this extension so I don't have to think about the platform differences:
extension View {
#if os(iOS)
func onBackground(_ f: #escaping () -> Void) -> some View {
self.onReceive(
NotificationCenter.default.publisher(for: UIApplication.willResignActiveNotification),
perform: { _ in f() }
)
}
func onForeground(_ f: #escaping () -> Void) -> some View {
self.onReceive(
NotificationCenter.default.publisher(for: UIApplication.didBecomeActiveNotification),
perform: { _ in f() }
)
}
#else
func onBackground(_ f: #escaping () -> Void) -> some View {
self.onReceive(
NotificationCenter.default.publisher(for: NSApplication.willResignActiveNotification),
perform: { _ in f() }
)
}
func onForeground(_ f: #escaping () -> Void) -> some View {
self.onReceive(
NotificationCenter.default.publisher(for: NSApplication.didBecomeActiveNotification),
perform: { _ in f() }
)
}
#endif
}
As expected, I use it as such:
AppView()
.onBackground {
print("my background")
}
.onForeground {
print("my foreground")
}
Use inside scene root view (usually ContentView)
Tested with Xcode 12 / iOS 14 as worked.
struct ContentView: View {
#Environment(\.scenePhase) private var scenePhase
var body: some View {
TestView()
.onChange(of: scenePhase) { phase in
switch phase {
case .active:
print(">> your code is here on scene become active")
case .inactive:
print(">> your code is here on scene become inactive")
case .background:
print(">> your code is here on scene go background")
default:
print(">> do something else in future")
}
}
}
}
I've been testing with Xcode 12 beta 3 and iOS/iPadOS 14 beta 3 and here's what I'm finding. Note that a lot of this involves supporting multiple windows, but the "SwiftUI lifecycle" projects default to turning that on, so I suspect you have it active already. In my original case I was porting an existing SwiftUI app from a SceneDelegate to using the new App struct, so I had multiple window support already active.
Here's the test View I'm using in a new testing app:
struct ContentView: View {
#Environment(\.scenePhase) private var scenePhase
var body: some View {
Text("Hello, world!").padding()
.onChange(of: scenePhase) { phase in
switch phase {
case .background:
print("PHASECHANGE: View entered background")
case .active:
print("PHASECHANGE: View entered active")
case .inactive:
print("PHASECHANGE: View entered inactive")
#unknown default:
print("PHASECHANGE: View entered unknown phase.")
}
}
}
}
(I have identical code in the App & Scene but they never print anything.)
The ScenePhase documentation claims that you can declare onChange inside the App, a Scene or a View. I don't see the App or Scene level versions ever execute, under any circumstance I can engineer, and the View level versions don't seem to execute completely correctly.
On hardware that doesn't support multiple windows (I use a 7th generation iPod touch) the View level closure executes every time. (Full disclosure, this iPod Touch is still running beta 2, but I don't think it's going to matter. Once I update it to b3 I'll mention it here if it matters.) EDIT (It did matter.)
On hardware running beta 2 that doesn't support multiple windows (a 7th generation iPod Touch) I see the app go into the background, back into the foreground, and so forth. On every app launch I'll see "View entered active" print.
On hardware that does support multiple windows (I use an older iPad Pro with the Lightning connector) I don't see the initial scene creation happen. (The first run does not trigger a "View entered active" message.) I do see subsequent background/foreground transitions. If I create a new scene from the iPad multi-tasking UI the second scene will trigger a "View entered active" log. Unfortunately I hadn't run this test on the iPad against beta 2, so I can't say if the behavior changed with b3 or not.
On my iPod Touch running iOS 14 beta 3 I see the same behavior as the iPad: the first launch doesn't print any phase change messages from the view, but does report subsequent background/foreground changes.
On the simulator it always behaves like the iPad hardware, even when I'm simulating an iPod Touch. I suspect this is because the simulator is running under the hood on the Mac and gets multiple window "support" this way. But I do see messages when I put the app in the background while running in the simulator, I'm just missing the initial "View entered active" message that I get from the actual hardware.
One final note: when I return an app from the foreground I first see "View entered inactive" and then I see "View entered active". When I background the app I see "View entered inactive", followed by "View entered background". I think this is expected behavior, but since other parts seem broken I wanted to mention it.
TL;DR:
I think you should be able to see most ScenePhase changes from a View, but you'll miss the initial app launch on iPads or in the simulator. And hopefully they will show up as expected for App and Scene objects in a later beta?
You can use the following extension:
public extension View {
func onScenePhaseChange(phase: ScenePhase, action: #escaping () -> ()) -> some View {
self.modifier(OnScenePhaseChangeModifier(phase: phase, action: action))
}
}
public struct OnScenePhaseChangeModifier: ViewModifier {
#Environment(\.scenePhase) private var scenePhase
public let phase: ScenePhase
public let action: () -> ()
public func body(content: Content) -> some View {
content
.onChange(of: scenePhase) { phase in
if (self.phase == phase) {
action()
}
}
}
}
Final usage:
ContentView()
.onScenePhaseChange(phase: .active) { print("scene activated!") }
.onScenePhaseChange(phase: .background) { print("scene backgrounded!") }
.onScenePhaseChange(phase: .inactive) { print("scene inactive!") }
In my case, I put "#Environment(.scenePhase) private var scenePhase" in ContentView. Then the onChange works in the child views.