SwiftUI - Open a specific View when user opens a Push Notification - push-notification

Question

A have an app made in SwiftUI, with Parse used for DB.
I'm some parts of the app i've integrated some cloud functions that send notifications (for example: when someone send's you a message, you will receive a push notification triggered by that cloud function).
In the past days i'm struggling and searching for how to open a specific view when you press the Notification to open the app.
I've found some solutions, but could not make them work.
This is the code that i have so far :
class AppDelegate: NSObject, UIApplicationDelegate, UNUserNotificationCenterDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
//Parse Intialization
...
//notifications
registerForPushNotifications()
//Notification Badge
UIApplication.shared.applicationIconBadgeNumber = 0
// start notification while app is in Foreground
UNUserNotificationCenter.current().delegate = self
return true
}
// This function will be called right after user tap on the notification
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void) {
print("app opened from PushNotification tap")
UIApplication.shared.applicationIconBadgeNumber = 0
completionHandler()
}
}
#main
struct MyApp: App {
#UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
var body: some Scene {
WindowGroup {
ContentView(currentTab: Tab.home)
}
}
}
The app prints "app opened from PushNotification tap", but if I put a variable in AppDelegate and I listen for changes in ContentView with .onReceive or .onChange for that variable, nothing is hapenning
struct ContentView: View {
#ObservedObject var appState = AppState()
#State var currentTab : Tab
#State var noReloadAddItemView = false
var body: some View {
TabView(selection: $appState.currentTab) {
NavigationView {
HomeView(appState: appState, noReloadAddItemView: $noReloadAddItemView)
}
.tabItem {
if appState.currentTab == .home {
Image(systemName: "house.fill")
} else {
Image(systemName: "house")
}
Text(LocalizedStringKey("HomeTabMenu"))
}.tag(Tab.home)
NavigationView {
SearchView(appState: appState, noReloadAddItemView: $noReloadAddItemView)
}
.tabItem {
if appState.currentTab == .search {
Image(systemName: "magnifyingglass.circle.fill")
} else {
Image(systemName: "magnifyingglass")
}
Text(LocalizedStringKey("SearchTabMenu"))
}.tag(Tab.search)
NavigationView {
AddItemView(appState: appState, noReloadAddItemView: $noReloadAddItemView)
}
.tabItem {
if appState.currentTab == .add {
Image(systemName: "plus.circle.fill")
} else {
Image(systemName: "plus.circle")
}
Text(LocalizedStringKey("SellTabMenu"))
}.tag(Tab.add)
NavigationView {
ShoppingCartFavoritesView(appState: appState, noReloadAddItemView: $noReloadAddItemView)
}
.tabItem {
if appState.currentTab == .favorites {
Image(systemName: "cart.fill")
} else {
Image(systemName: "cart")
}
Text(LocalizedStringKey("CartTabMenu"))
}.tag(Tab.favorites)
NavigationView {
ProfileView(appState: appState, noReloadAddItemView: $noReloadAddItemView)
}
.tabItem {
if appState.currentTab == .profile {
Image(systemName: "person.fill")
} else {
Image(systemName: "person")
}
Text(LocalizedStringKey("ProfileTabMenu"))
}.tag(Tab.profile)
}
.accentColor(Color("ColorMainDark"))
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView(currentTab: Tab.home)
}
}
class AppState: ObservableObject {
#Published var currentTab : Tab = .home
}
enum Tab {
case home, search, add, favorites, profile
}

Answer 1

You need some sort of shared state that you can modify that SwiftUI knows to react to. An ObservableObject is perfect for this:
class AppState: ObservableObject {
static let shared = AppState()
#Published var pageToNavigationTo : String?
}
Then, to listen to it and respond to it, you can do a couple different methods in your main view.
Option 1 -- NavigationLink binding based on the value of the ObservedObject:
struct ContentView : View {
#ObservedObject var appState = AppState.shared //<-- note this
#State var navigate = false
var pushNavigationBinding : Binding<Bool> {
.init { () -> Bool in
appState.pageToNavigationTo != nil
} set: { (newValue) in
if !newValue { appState.pageToNavigationTo = nil }
}
}
var body: some View {
NavigationView {
Text("My content")
.overlay(NavigationLink(destination: Dest(message: appState.pageToNavigationTo ?? ""),
isActive: pushNavigationBinding) {
EmptyView()
})
}
}
}
struct Dest : View {
var message : String
var body: some View {
Text("\(message)")
}
}
Or, you could use onReceive:
struct ContentView : View {
#ObservedObject var appState = AppState.shared
#State var navigate = false
var body: some View {
NavigationView {
VStack {
if navigate {
NavigationLink(destination: Text("Test"), isActive: $navigate ) {
EmptyView()
}
}
Text("My content")
.onReceive(appState.$pageToNavigationTo) { (nav) in
if nav != nil { navigate = true }
}
}
}
}
}
I'll leave the implementation details of your specific NavigationView, NavigationLink, TabView, etc to you, but this should get you started.
Finally, a fully-functional minimal example that mocks a notification and shows how the navigation view:
class AppDelegate: NSObject, UIApplicationDelegate, UNUserNotificationCenterDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
print("Dispatch")
AppState.shared.pageToNavigationTo = "test"
}
return true
}
}
class AppState: ObservableObject {
static let shared = AppState()
#Published var pageToNavigationTo : String?
}
#main
struct MultiWindowApp: App {
#UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
struct ContentView : View {
#ObservedObject var appState = AppState.shared
#State var navigate = false
var pushNavigationBinding : Binding<Bool> {
.init { () -> Bool in
appState.pageToNavigationTo != nil
} set: { (newValue) in
if !newValue { appState.pageToNavigationTo = nil }
}
}
var body: some View {
NavigationView {
Text("My content")
.overlay(NavigationLink(destination: Dest(message: appState.pageToNavigationTo ?? ""),
isActive: pushNavigationBinding) {
EmptyView()
})
}
}
}
struct Dest : View {
var message : String
var body: some View {
Text("\(message)")
}
}