how can I wait for the result of an async function that loads data for storekit2 in swiftui?
Swift UI Code:
struct SettingsForm : View {
#State var selectedRegion: Int = 0
#State var alwaysOriginalTitle: Bool = false
#State
private var products: [Product] = []
#Environment(\.presentationMode) var presentationMode
let productIds = ["premium"]
init() {
loadProducts()
}
private func loadProducts() async throws {
self.products = await Product.products(for: productIds)
print(self.products)
}
...
You just need to check if your products are loaded, and if not, show for example a ProgressView
struct SettingsForm : View {
#State private var products: [Product]?
let productIds = ["premium"]
var body: some View {
if let products {
// Display list of products
} else {
ProgressView("Loading products")
.task {
do {
try await loadProducts()
} catch {
// handleError
}
}
}
}
func loadProducts() async throws {
self.products = try await Product.products(for: productIds)
}
}
Related
My preview crashes with the error: Failed to get FirebaseApp instance. Please call FirebaseApp.configure() before using Firestore. My guess is it is because in ProfileViewController I try to access firebase and I configure firebase in an extra class that is not called before. Is there any workaround? I tried setting var Firebasemanager = FirebaseManager() in preview but it still fails.
This is the class where I call configure():
class FirebaseManager: NSObject {
let auth: Auth
let storage: Storage
let firestore: Firestore
var currentUser: ChatUser? // User?
static let shared = FirebaseManager()
override init() {
FirebaseApp.configure()
self.auth = Auth.auth()
self.storage = Storage.storage()
self.firestore = Firestore.firestore()
super.init()
}
}
This are all the States of my View:
#Environment(\.presentationMode) var presentationMode
#State var shouldShowImagePicker: Bool = false
#State var loginStatusMessage = ""
#EnvironmentObject var viewRouter: ViewRouter
#StateObject var profileController = ProfileViewController()
#ObservedObject var userViewModel = UserViewModel()
This is what my Preview looks like:
struct ProfileView_Previews: PreviewProvider {
static var previews: some View {
ProfileView(presentationMode: Environment(\.presentationMode), shouldShowImagePicker: false, loginStatusMessage: "", profileController: ProfileViewController(), userViewModel: UserViewModel()).environmentObject(ViewRouter())
}
}
EDIT:
This is the ProfileViewController:
class ProfileViewController: ObservableObject {
let uid = FirebaseManager.shared.auth.currentUser?.uid ?? ""
let store = FirebaseManager.shared.firestore
func deleteCurrentTrack() async {
try? await store.collection("current_track").document(uid).delete()
}
}
This is where I call it in my ProfileView:
struct ProfileView: View {
var body: some View {
Button() {
Task {
await profileController.deleteCurrentTrack()
try await FirebaseManager.shared.auth.currentUser?.delete()
}
} label: {
Text("Delete track")
}
}
}
The reason my preview failed was because of UserViewModel.
At the top I set let db = Firestore.firestore(), deleting this solved the problem.
class UserViewModel: ObservableObject {
let db = Firestore.firestore()
#Published var chatUser: ChatUser?
init() {
fetchCurrentUser()
}
func fetchCurrentUser() {
guard let uid = FirebaseManager.shared.auth.currentUser?.uid else {
return
}
FirebaseManager.shared.firestore.collection("users").document(uid).getDocument { snapshot, error in
if let error = error {
print("Failed to fetch current user: ", error)
}
self.chatUser = try? snapshot?.data(as: ChatUser.self)
FirebaseManager.shared.currentUser = self.chatUser
}
}
}
My Preview looks like this:
struct ProfileView_Previews: PreviewProvider {
static var previews: some View {
ProfileView().environmentObject(ViewRouter())
}
}
My aim is the change data in DetailView(). Normally in this case I'm using #State + #Binding and it's works fine with static data, but when I trying to update ViewModel with data from network request I'm loosing functionality of #State (new data doesn't passing to #State value it's stays empty). I checked network request and decoding process - everything ok with it. Sorry my code example a bit long but it's the shortest way that I found to recreate the problem...
Models:
struct LeagueResponse: Decodable {
var status: Bool?
var data: [League] = []
}
struct League: Codable, Identifiable {
let id: String
let name: String
var seasons: [Season]?
}
struct SeasonResponse: Codable {
var status: Bool?
var data: LeagueData?
}
struct LeagueData: Codable {
let name: String?
let desc: String
let abbreviation: String?
let seasons: [Season]
}
struct Season: Codable {
let year: Int
let displayName: String
}
ViewModel:
class LeagueViewModel: ObservableObject {
#Published var leagues: [League] = []
init() {
Task {
try await getLeagueData()
}
}
private func getLeagueData() async throws {
let (data, _) = try await URLSession.shared.data(from: URL(string: "https://api-football-standings.azharimm.site/leagues")!)
guard let leagues = try? JSONDecoder().decode(LeagueResponse.self, from: data) else {
throw URLError(.cannotParseResponse)
}
await MainActor.run {
self.leagues = leagues.data
}
}
func loadSeasons(forLeague id: String) async throws {
let (data, _) = try await URLSession.shared.data(from: URL(string: "https://api-football-standings.azharimm.site/leagues/\(id)/seasons")!)
guard let seasons = try? JSONDecoder().decode(SeasonResponse.self, from: data) else {
throw URLError(.cannotParseResponse)
}
await MainActor.run {
if let responsedLeagueIndex = leagues.firstIndex(where: { $0.id == id }),
let unwrappedSeasons = seasons.data?.seasons {
leagues[responsedLeagueIndex].seasons = unwrappedSeasons
print(unwrappedSeasons) // successfully getting and parsing data
}
}
}
}
Views:
struct ContentView: View {
#StateObject var vm = LeagueViewModel()
var body: some View {
NavigationView {
VStack {
if vm.leagues.isEmpty {
ProgressView()
} else {
List {
ForEach(vm.leagues) { league in
NavigationLink(destination: DetailView(league: league)) {
Text(league.name)
}
}
}
}
}
.navigationBarTitle(Text("Leagues"), displayMode: .large)
}
.environmentObject(vm)
}
}
struct DetailView: View {
#EnvironmentObject var vm: LeagueViewModel
#State var league: League
var body: some View {
VStack {
if let unwrappedSeasons = league.seasons {
List {
ForEach(unwrappedSeasons, id: \.year) { season in
Text(season.displayName)
}
}
} else {
ProgressView()
}
}
.onAppear {
Task {
try await vm.loadSeasons(forLeague: league.id)
}
}
.navigationBarTitle(Text("League Detail"), displayMode: .inline)
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
ChangeButton(selectedLeague: $league)
}
}
}
}
struct ChangeButton: View {
#EnvironmentObject var vm: LeagueViewModel
#Binding var selectedLeague: League // if remove #State the data will pass fine
var body: some View {
Menu {
ForEach(vm.leagues) { league in
Button {
self.selectedLeague = league
} label: {
Text(league.name)
}
}
} label: {
Image(systemName: "calendar")
}
}
}
Main goals:
Show selected league seasons data in DetailView()
Possibility to change seasons data in DetailView() when another league was chosen in ChangeButton()
You update view model but DetailView contains a copy of league (because it is value type).
The simplest seems to me is to return in callback seasons, so there is possibility to update local league as well.
func loadSeasons(forLeague id: String, completion: (([Season]) -> Void)?) async throws {
// ...
await MainActor.run {
if let responsedLeagueIndex = leagues.firstIndex(where: { $0.id == id }),
let unwrappedSeasons = seasons.data?.seasons {
leagues[responsedLeagueIndex].seasons = unwrappedSeasons
completion?(unwrappedSeasons) // << here !!
}
}
}
and make task dependent on league id so selection would work, like:
struct DetailView: View {
#EnvironmentObject var vm: LeagueViewModel
#State var league: League
var body: some View {
VStack {
// ...
}
.task(id: league.id) { // << here !!
Task {
try await vm.loadSeasons(forLeague: league.id) {
league.seasons = $0 // << update local copy !!
}
}
}
Tested with Xcode 13.4 / iOS 15.5
Test module is here
One question is if you already made LeagueViewModel an ObservableObject, why don't you display from it directly, and simply pass an id to your DetailView?
So your detail view will be:
struct DetailView: View {
#EnvironmentObject var vm: LeagueViewModel
#State var id: String
var body: some View {
VStack {
if let unwrappedSeasons = vm.leagues.first { $0.id == id }?.seasons {
List {
ForEach(unwrappedSeasons, id: \.year) { season in
Text(season.displayName)
}
}
} else {
ProgressView()
}
}
.task(id: id) {
Task {
try await vm.loadSeasons(forLeague: id)
}
}
.navigationBarTitle(Text("League Detail"), displayMode: .inline)
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
ChangeButton(selectedId: $id)
}
}
}
}
The view will automatically update season data as it loads them.
I'm trying to update my view, only after the Async call is resolved. In the below code the arrayOfTodos.items comes in asynchronously a little after TodoListApp is rendered. The problem I'm having is that when onAppear runs, self.asyncTodoList.items is always empty since it hasn't received the values of the array yet from the network call. I'm stuck trying to figure out how to hold off on running onAppear until after the Promise is resolved, like with a completion handler?? And depending on the results of the network call, then modify the view. Thanks for any help! I've been stuck on this longer than I'll ever admit!
struct ContentView: View {
#StateObject var arrayOfTodos = AsyncGetTodosNetworkCall()
var body: some View {
TodoListApp(asyncTodoList: arrayOfTodos)
}
}
struct TodoListApp: View {
#ObservedObject var asyncTodoList: AsyncGetTodosNetworkCall
#State private var showPopUp: Bool = false
var body: some View {
NavigationView {
ZStack {
VStack {
Text("Top Area")
Text("List Area")
}
if self.showPopUp == true {
VStack {
Text("THIS IS MY POPUP!")
Text("No Items Added Yet")
}.frame(width: 300, height: 400)
}
}.onAppear {
let arrayItems = self.asyncTodoList
if arrayItems.items.isEmpty {
self.showPopUp = true
}
/*HERE! arrayItems.items.isEmpty is ALWAYS empty when onAppear
runs since it's asynchronous. What I'm trying to do is only
show the popup if the array is empty after the promise is
resolved.
What is happening is even if array resolved with multiple todos,
the popup is still showing because it was initially empty on
first run. */
}
}
}
}
class AsyncGetTodosNetworkCall: ObservableObject {
#AppStorage(DBUser.userID) var currentUserId: String?
private var REF_USERS = DB_BASE.collection(DBCOLLECTION.appUsers)
#Published var items = [TodoItem]()
func fetchTodos(toDetach: Bool) {
guard let userID = currentUserId else {
return
}
let userDoc = REF_USERS.document(String(userID))
.collection(DBCOLLECTION.todos)
.addSnapshotListener({ (querySnapshot, error) in
guard let documents = querySnapshot?.documents else {
print("No Documents Found")
return
}
self.items = documents.map { document -> TodoItem in
let todoID = document.documentID
let todoName = document.get(ToDo.todoName) as? String ?? ""
let todoCompleted = document.get(Todo.todoCompleted) as? Bool ?? false
return TodoItem(
id: todoID,
todoName: todoName,
todoCompleted: todoCompleted
)
}
})
if toDetach == true {
userDoc.remove()
}
}
}
While preparing my question, i found my own answer. Here it is in case someone down the road might run into the same issue.
struct ContentView: View {
#StateObject var arrayOfTodos = AsyncGetTodosNetworkCall()
#State var hasNoTodos: Bool = false
func getData() {
self.arrayOfTodos.fetchTodos(toDetach: false) { noTodos in
if noTodos {
self.hasNoTodos = true
}
}
}
func removeListeners() {
self.arrayOfTodos.fetchTodos(toDetach: true)
}
var body: some View {
TabView {
TodoListApp(asyncTodoList: arrayOfTodos, hasNoTodos : self.$hasNoTodos)
}.onAppear(perform: {
self.getData()
}).onDisappear(perform: {
self.removeListeners()
})
}
}
struct TodoListApp: View {
#ObservedObject var asyncTodoList: AsyncGetTodosNetworkCall
#Binding var hasNoTodos: Bool
#State private var hidePopUp: Bool = false
var body: some View {
NavigationView {
ZStack {
VStack {
Text("Top Area")
ScrollView {
LazyVStack {
ForEach(asyncTodoList.items) { item in
HStack {
Text("\(item.name)")
Spacer()
Text("Value")
}
}
}
}
}
if self.hasNoTodos == true {
if self.hidePopUp == false {
VStack {
Text("THIS IS MY POPUP!")
Text("No Items Added Yet")
}.frame(width: 300, height: 400)
}
}
}
}
}
}
class AsyncGetTodosNetworkCall: ObservableObject {
#AppStorage(DBUser.userID) var currentUserId: String?
private var REF_USERS = DB_BASE.collection(DBCOLLECTION.appUsers)
#Published var items = [TodoItem]()
func fetchTodos(toDetach: Bool, handler: #escaping (_ noTodos: Bool) -> ()) {
guard let userID = currentUserId else {
handler(true)
return
}
let userDoc = REF_USERS.document(String(userID))
.collection(DBCOLLECTION.todos)
.addSnapshotListener({ (querySnapshot, error) in
guard let documents = querySnapshot?.documents else {
print("No Documents Found")
handler(true)
return
}
self.items = documents.map { document -> TodoItem in
let todoID = document.documentID
let todoName = document.get(ToDo.todoName) as? String ?? ""
let todoCompleted = document.get(Todo.todoCompleted) as? Bool ?? false
return TodoItem(
id: todoID,
todoName: todoName,
todoCompleted: todoCompleted
)
}
handler(false)
})
if toDetach == true {
userDoc.remove()
}
}
}
I am creating an application using RealmSwift.
The following implementation crashed when deleting related data.
After removing only "UnderlayerItem", it succeeded.
Crash when deleting UnderlayerItem and deleting Item.
The error is:
Thread 1: Exception: "The RLMArray has been invalidated or the object
containing it has been deleted."
How do I delete without crashing?
struct ListView: View {
#ObservedObject private var fetcher = Fetcher()
#State private var title = ""
var body: some View {
NavigationView {
VStack {
TextField("add", text: $title) {
let item = Item()
item.title = self.title
let realm = try! Realm()
try! realm.write {
realm.add(item)
}
self.title = ""
}
ForEach(self.fetcher.items) { (item: Item) in
NavigationLink(destination: DetailView(item: item, id: item.id)) {
Text(item.title)
}
}
}
}
}
}
struct DetailView: View {
var item: Item
var id: String
#State private var title = ""
#ObservedObject private var fetcher = Fetcher()
#Environment(\.presentationMode) private var presentationMode: Binding<PresentationMode>
var body: some View {
VStack {
TextField("add", text: $title) {
let realm = try! Realm()
if let item = realm.objects(Item.self).filter("id == '\(self.id)'").first {
try! realm.write() {
let underlayerItem = UnderlayerItem()
underlayerItem.title = self.title
item.underlayerItems.append(underlayerItem)
}
}
self.title = ""
}
ForEach(self.item.underlayerItems) { (underlayerItems: UnderlayerItem) in
Text(underlayerItems.title)
}
Button(action: {
self.presentationMode.wrappedValue.dismiss()
self.fetcher.delete(id: self.id)
}) {
Text("Delete")
}
}
}
}
class Fetcher: ObservableObject {
var realm = try! Realm()
var objectWillChange: ObservableObjectPublisher = .init()
private(set) var items: Results<Item>
private var notificationTokens: [NotificationToken] = []
init() {
items = realm.objects(Item.self)
notificationTokens.append(items.observe { _ in
self.objectWillChange.send()
})
}
func delete(id: String) {
guard let item = realm.objects(Item.self).filter("id == '\(id)'").first else { return }
try! realm.write() {
for underlayerItem in item.underlayerItems {
realm.delete(realm.objects(UnderlayerItem.self).filter("id == '\(underlayerItem.id)'").first!)
}
}
try! realm.write() {
realm.delete(item)
}
}
}
class Item: Object, Identifiable {
#objc dynamic var id = NSUUID().uuidString
#objc dynamic var title = ""
#objc dynamic var createdAt = NSDate()
let underlayerItems: List<UnderlayerItem> = List<UnderlayerItem>()
override static func primaryKey() -> String? {
return "id"
}
}
class UnderlayerItem: Object, Identifiable {
#objc dynamic var id = NSUUID().uuidString
#objc dynamic var title = ""
#objc dynamic var createdAt = NSDate()
override static func primaryKey() -> String? {
return "id"
}
}
You don't need to iterate over the objects in the list to delete them. Just do this
try! realm.write() {
realm.delete(item.underlayerItems)
}
I believe it's crashing because you're attempting to access an item that was deleted
self.item.underlayerItems
I am currently getting a list of sites from a Firebase Firestore and then returning them to a list in SwiftUI. Each list item has a label and Toggle. The list of sites is dynamic so could be anywhere from 1-30+. How can I create an #State or similar bindable to observe each toggle's state.
I am currently rendering to UI with the following
#State private var SiteA = false
Form {
Section (header: Text("Select Sites")) {
ForEach(siteData.sites) { site in
HStack {
Toggle(isOn: self.$SiteA) {
Text(site.name)
Spacer()
}
}
}
}
}
Sites are retrieved using a Bindable object
import SwiftUI
import Combine
import Firebase
import FirebaseFirestore
struct Message: Identifiable {
var title: String
var messageBody: String
var sentBy: String
var targetSite: String
var expired: Bool
var timeStamp: Timestamp
var emergency: Bool
var id: String
}
struct Site: Identifiable {
var id: String
var name: String
}
class FirestoreMessages : ObservableObject {
var db = Firestore.firestore()
var didChange = PassthroughSubject<FirestoreMessages, Never>()
#Published var messages: [Message] = [] {
didSet{ didChange.send(self) }
}
#Published var sites: [Site] = [] {
didSet { didChange.send(self) }
}
func listen() {
db.collection("messages")
.whereField("expired", isEqualTo: false)
.addSnapshotListener { (snap, error) in
if error != nil {
print("Firebase Snapshot Error: \(error?.localizedDescription ?? "")")
} else {
self.messages.removeAll()
for doc in snap!.documents {
let title = doc["title"] as! String
let messageBody = doc["body"] as! String
let sentBy = doc["sentBy"] as! String
let targetSite = doc["targetSite"] as! String
let expired = doc["expired"] as! Bool
let timeStamp = doc["timeStamp"] as! Timestamp
let emergency = doc["emergency"] as! Bool
let id = doc.documentID
let message = Message(
title: title,
messageBody: messageBody,
sentBy: sentBy,
targetSite: targetSite,
expired: expired,
timeStamp: timeStamp,
emergency: emergency,
id: id)
self.messages.append(message)
}
}
}
}
func getSites() {
db.collection("sites")
.order(by: "name", descending: false)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting docs: \(err)")
} else {
self.sites.removeAll()
for document in querySnapshot!.documents {
let doc = document.data()
let id = document.documentID
let name = doc["name"] as! String
let site = Site(id: id, name: name)
self.sites.append(site)
}
}
}
}
}
How can I create an #State unique to each list item to monitor their states individually?
The answer to your problem is composition. Move the HStack and enclosed Toggle to a SiteRow view where each row has its own State.
struct SiteRow: View {
#State private var state: Bool = false
private let site: Site
init(_ site: Site) {
self.site = site
self.state = site.isOn
}
var body: some View {
HStack {
Toggle(isOn: self.$state) {
Text(site.name)
Spacer()
}
}
}
}
Then...
ForEach(siteData.sites) { site in SiteRow(site) }