I know that this sounds a bit dumb, but how do you call a function only once. I have a tab bar at the bottom of my app, and every time that it is called, the name that I got from my firebase database, keeps on being added. For example, the name in firebase is Bob. The app for the first time will display Bob. Then you would click on the settings, and go back to the home view. Then the app will say BobBob, and over and over again. How do I make this stop.
Code:
import SwiftUI
import Firebase
struct HomeView: View {
#State var name = ""
var body: some View {
NavigationView {
ZStack {
VStack{
Text("Welcome \(name)")
.font(.title)
Text("Upcoming Lessions/Reservations:")
.bold()
.padding()
Divider()
}
}
}
.navigationTitle("Home")
.onAppear(perform: {
downloadNameServerData()
})
}
private func downloadNameServerData() {
let db = Firestore.firestore()
db.collection("users").addSnapshotListener {(snap, err) in
if err != nil{
print("\(String(describing: err))")
return
}
for i in snap!.documentChanges {
_ = i.document.documentID
if let Name = i.document.get("Name") as? String {
DispatchQueue.main.async {
name.append(Name)
print("\(name)")
}
}
}
}
}
}
struct HomeView_Previews: PreviewProvider {
static var previews: some View {
HomeView()
}
}
import SwiftUI
import Firebase
struct HomeView: View {
#State var name = ""
var body: some View {
NavigationView {
ZStack {
VStack{
Text("Welcome \(name)")
.font(.title)
Text("Upcoming Lessions/Reservations:")
.bold()
.padding()
Divider()
}
}
}
.navigationTitle("Home")
.onAppear(perform: {
downloadNameServerData()
})
}
private func downloadNameServerData() {
if !name.isEmpty { return }
let db = Firestore.firestore()
db.collection("users").addSnapshotListener {(snap, err) in
if err != nil{
print("\(String(describing: err))")
return
}
for i in snap!.documentChanges {
_ = i.document.documentID
if let Name = i.document.get("Name") as? String {
DispatchQueue.main.async {
name = Name
print("\(name)")
}
}
}
}
}
}
struct HomeView_Previews: PreviewProvider {
static var previews: some View {
HomeView()
}
}
Did you consider only loading the name if you don't have one yet?
.onAppear(perform: {
if (name == null) downloadNameServerData()
})
Related
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
}
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)")
}
}
I have a Game-object that may hold an image. Whenever an image URL is found for a game a new instance of GameImage-object should be created. It will then fetch the image and populate the UIImage property. When this happens the UI should be updated presenting the image.
class Game: ObservableObject {
#Published var image: GameImage?
}
class GameImage: ObservableObject {
let url: URL
#Published var image: UIImage?
private var cancellable: AnyCancellable?
init(url: URL) {
self.url = url
}
func fetch() {
self.cancellable = URLSession.shared.dataTaskPublisher(for: self.url)
.map { UIImage(data: $0.data) }
.replaceError(with: nil)
.receive(on: DispatchQueue.main)
.sink(receiveValue: { [weak self] (image) in
guard let self = self else { return }
self.image = image
print(self.url)
print(self.image)
})
}
func cancel() {
cancellable?.cancel()
}
deinit {
cancel()
}
}
struct ContentView: View {
#StateObject var game = Game()
var body: some View {
VStack {
if let image = game.image?.image {
Image(uiImage: image)
} else {
Text("No image.")
}
}
.onAppear(perform: {
guard let gameImageURL = URL(string: "https://cf.geekdo-images.com/itemrep/img/oVEpcbtyWkJjIjk1peTJo6hI1yk=/fit-in/246x300/pic4884996.jpg") else { return }
game.image = GameImage(url: gameImageURL)
game.image!.fetch()
})
}
}
The problem is. After fetch is done the debug console will show that image contains an UIImage. However the UI does not update to show the image. What am I missing here?
There is much more simpler solution than chaining ObservableObject, just separate dependent part into standalone subview... and all will work automatically.
Here is possible approach. Tested with Xcode 12 / iOS 14.
struct ContentView: View {
#StateObject var game = Game()
var body: some View {
VStack {
if nil != game.image {
GameImageView(vm: game.image!)
}
}
.onAppear(perform: {
guard let gameImageURL = URL(string: "https://cf.geekdo-images.com/itemrep/img/oVEpcbtyWkJjIjk1peTJo6hI1yk=/fit-in/246x300/pic4884996.jpg") else { return }
game.image = GameImage(url: gameImageURL)
game.image!.fetch()
})
}
}
struct GameImageView: View {
#ObservedObject var vm: GameImage
var body: some View {
if let image = vm.image {
Image(uiImage: image)
} else {
Text("No image.")
}
}
}
So i have a sessionStore:
class SessionStore: ObservableObject {
var handle: AuthStateDidChangeListenerHandle?
#Published var isLoggedIn = false
#Published var userInSession: User?
func listenAuthenticationState() {
handle = Auth.auth().addStateDidChangeListener({(auth, user) in
if let user = user {
let firestoreGetUser = Firestore.firestore().collection("users").document(user.uid)
firestoreGetUser.getDocument{(document, error) in
if let dict = document?.data() {
guard let decodedUser = try? User.init(fromDictionary: dict) else { return }
self.userInSession = decodedUser
print("decoded user = \(decodedUser)")
}
}
self.isLoggedIn = true
print("user logged in")
} else {
self.isLoggedIn = false
self.userInSession = nil
print("no one logged in")
}
})
}
func logout() {
do {
try Auth.auth().signOut()
} catch {
}
}
func unbind() {
if let handle = handle {
Auth.auth().removeStateDidChangeListener(handle)
}
}
deinit {
unbind()
}
}
Its working as expected, I am able to sign in etc.
I have the following to pull the current user data:
import Foundation
import Firebase
import FirebaseAuth
import FirebaseFirestore
class ProfileViewModel: ObservableObject {
var uid: String = ""
var email: String = ""
var username: String = ""
var profileURL: String = ""
var bio: String = ""
var occupation: String = ""
var city: String = ""
func LoadAUser(userId: String) {
Firestore.firestore().collection("users").document(userId).getDocument{(snapshot, error) in
guard let snap = snapshot else {
print("error fetching data")
return
}
let dict = snap.data()
guard let decodedUser = try? User.init(fromDictionary: dict!) else { return }
print("decoded user - load user - \(decodedUser)")
}
}
}
In my view im trying to call it like:
import SwiftUI
struct ProfileView: View {
#EnvironmentObject var session: SessionStore
#ObservedObject var profileViewModel = ProfileViewModel()
func loadUserData() {
profileViewModel.LoadAUser(userId: session.userInSession!.uid)
}
var body: some View {
VStack {
Text("Edit Profile")
.fontWeight(.semibold)
.font(.system(.title, design: .rounded))
.foregroundColor(Color("startColor"))
Spacer()
VStack(alignment: .leading) {
Text("view")
}.padding()
.onAppear(perform: loadUserData)
}
}
struct ProfileView_Previews: PreviewProvider {
static var previews: some View {
ProfileView()
}
}
Im using .onAppear(perform: loadUserData) which is causing an issue - Thread1: Fatal error: Unexpectedly found nil while unwrapping
I also tried:
init() {
profileViewModel.LoadAUser(userId: session.userInSession!.uid)
}
But this also causes the same error.
The thing is I should only be able to get to this view if I'm logged in as this already works:
struct InitialView: View {
#EnvironmentObject var session: SessionStore
func listen() {
session.listenAuthenticationState()
}
var body: some View {
Group {
if session.isLoggedIn {
MainView()
} else {
NavigationView {
SignUpView()
}
}
}.onAppear(perform: listen)
}
}
I have an initialView()
struct InitialView: View {
#EnvironmentObject var session: SessionStore
func listen() {
session.listenAuthenticationState()
}
var body: some View {
Group {
if session.isLoggedIn {
MainView()
} else {
NavigationView {
SignUpView()
}
}
}.onAppear(perform: listen)
}
}
which takes you to the MainView() which has tabs to control which screen you can navigate to, then from here i can go to ProfileView()
Anyway by the logic of provided code it is more correct to activate isLoggedIn in
let firestoreGetUser = Firestore.firestore().collection("users").document(user.uid)
firestoreGetUser.getDocument{(document, error) in
if let dict = document?.data() {
guard let decodedUser = try? User.init(fromDictionary: dict) else { return }
self.userInSession = decodedUser
print("decoded user = \(decodedUser)")
self.isLoggedIn = true // << here !!
print("user logged in")
}
}
So whats worked for me is passing in Auth instead of session data:
func loadUserData() {
profileViewModel.LoadAUser(userId: Auth.auth().currentUser!.uid)
}
I have this view:
import SwiftUI
struct SectionView1: View {
let dateStr:String
#Binding var isSectionView:Bool
var body: some View {
HStack {
Button(action: {
self.isSectionView.toggle()
}) {
Image(systemName: isSectionView ? "chevron.down.circle" : "chevron.right.circle")
}
Text("Media del \(dateStr)")
}
}
}
which will be called from view:
import SwiftUI
import Photos
struct MediaView: View {
let geoFolder:GeoFolderCD
#State private var assetsForDate = [String :[PHAsset]]()
#State private var isSectionViewArray:[String:Bool] = [:]
var body: some View {
List {
ForEach(assetsForDate.keys.sorted(by: > ), id: \.self) { dateStr in
Section {
SectionView1(dateStr: dateStr,
isSectionView: self.$isSectionViewArray[dateStr, default: true])
}
}
}
.onAppear {
self.assetsForDate = FetchMediaUtility().fetchGeoFolderAssetsForDate(geoFolder: geoFolderStruct, numAssets: numMediaToFetch)
for dateStr in self.assetsForDate.keys.sorted() {
self.isSectionViewArray[dateStr] = true
}
}
}
}
but I have the error: Subscript index of type '() -> Bool' in a key path must be Hashable in isSectionView: self.$isSectionViewArray[dateStr, default: true]
Why isSectionViewArray:[String:Bool] = [:] is not Hasbable?
How can modify the code for work?
If I remove, in SectionView, #Binding var isSectionView:Bool, the code work fine, or if I set, from SectionView, #Binding var isSectionViewArray:[String:Bool] = [:], the code work fine.
You can write your own binding with the below code and it should work
var body: some View {
List {
ForEach(assetsForDate.keys.sorted(by: > ), id: \.self) { dateStr in
let value = Binding<Bool>(get: { () -> Bool in
return self.isSectionViewArray[dateStr, default: true]
}) { (value) in
}
Section {
SectionView1(dateStr: dateStr,
isSectionView: value)
}
}
}
.onAppear {
self.assetsForDate = FetchMediaUtility().fetchGeoFolderAssetsForDate(geoFolder: geoFolderStruct, numAssets: numMediaToFetch)
for dateStr in self.assetsForDate.keys.sorted() {
self.isSectionViewArray[dateStr] = true
}
}
}
Can someone tell me what I am doing wrong? I am using Swiftui and firebase database. I am not seeing any error or any data on the screen. I did install the Pods and checked the security rules as well in console. I tried couple other methods, but this was exactly same from youtube tutorials except the collection name and fields.
import SwiftUI
import Firebase
struct Calories: View {
#ObservedObject var data = getData()
var body: some View {
NavigationView{
ZStack(alignment: .top){
GeometryReader{_ in
// Home View....
Text("Home")
}.background(Color("Color").edgesIgnoringSafeArea(.all))
CustomSearchBar(data: self.$data.datas).padding(.top)
}.navigationBarTitle("")
.navigationBarHidden(true)
}
}
}
struct Calories_Previews: PreviewProvider {
static var previews: some View {
Calories()
}
}
struct CustomSearchBar : View {
#State var txt = ""
#Binding var data : [dataType]
var body : some View{
VStack(spacing: 0){
HStack{
TextField("Search", text: self.$txt)
if self.txt != ""{
Button(action: {
self.txt = ""
}) {
Text("Cancel")
}
.foregroundColor(.black)
}
}.padding()
if self.txt != ""{
if self.data.filter({$0.item.lowercased().contains(self.txt.lowercased())}).count == 0{
Text("No Results Found").foregroundColor(Color.black.opacity(0.5)).padding()
}
else{
List(self.data.filter{$0.item.lowercased().contains(self.txt.lowercased())}){i in
NavigationLink(destination: Detail(data: i)) {
Text(i.item)
}
}.frame(height: UIScreen.main.bounds.height / 5)
}
}
}.background(Color.white)
.padding()
}
}
class getData : ObservableObject{
#Published var datas = [dataType]()
init() {
let db = Firestore.firestore()
db.collection("HSCal").getDocuments { (snap, err) in
if err != nil{
print((err?.localizedDescription)!)
return
}
for i in snap!.documents{
let id = i.documentID
let item = i.get("item") as! String
let cal = i.get("cal") as! String
self.datas.append(dataType(id: id, item: item, cal: cal))
}
}
}
}
struct dataType : Identifiable {
var id : String
var item : String
var cal : String
}
struct Detail : View {
var data : dataType
var body : some View{
Text(data.item)
}
}
did you put app bundle?
try in
struct Calories: View {
#EnvironmentObject var List: getData()
....
}
call
Calories().environmentObject(DataList)
declare somewhere
var DataList = getData()