How to use ObservedObject with Google Sign In - swift

Question

I am trying to observe if user logged in or not by Google sign in SDK using SwiftUI . the sign in is working fine and the print out is showing user is logged in successfully , but the UI is not changing it is like the observe not working or I am sure I miss something there .
App :
#main
struct test_app: App {
#AppStorage("settings") private var settings: Data = Data()
#Environment(\.scenePhase) var scenePhase
#UIApplicationDelegateAdaptor(test_delegate.self) private var appDelegate
var userInfo:Bool = false
#ObservedObject static var gd = GoogleDelegate()
init(){
//Google sign in
GIDSignIn.sharedInstance().delegate = test_app.gd
//Firebase
FirebaseApp.configure()
print("[APP] Init complete.")
}
var body: some Scene {
WindowGroup {
if userInfo {
w_home().onOpenURL(perform: { url in
print("[DEEP LINK] Incoming url: \(url)")
})
}else{
w_splash()
}
}.onChange(of: scenePhase) { (newScenePhase) in
switch newScenePhase {
case .background:
print("[APP] State : Background")
case .inactive:
print("[APP] State : Inactive")
case .active:
print("[APP] State : Active")
#unknown default:
print("[APP] State : Unknown")
}
}
}
}
GoogleDelegate class :
class GoogleDelegate: NSObject, GIDSignInDelegate, ObservableObject {
#Published var signedIn: Bool = false
public func signIn(){
// Maksure that there must be a presenting controller as a container
GIDSignIn.sharedInstance()?.presentingViewController = UIApplication.shared.windows.first?.rootViewController
//Google sign in
GIDSignIn.sharedInstance().clientID = FirebaseApp.app()?.options.clientID
GIDSignIn.sharedInstance().signIn()
signedIn = false
}
func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error!) {
if let error = error {
if (error as NSError).code == GIDSignInErrorCode.hasNoAuthInKeychain.rawValue {
print("[GSIN] The user has not signed in before or they have since signed out.")
} else {
print("[GSIN] \(error.localizedDescription)")
}
return
}
// If the previous `error` is null, then the sign-in was succesful
if GIDSignIn.sharedInstance().currentUser != nil {
print("[GSIN] Successful sign-in! \( String(describing: GIDSignIn.sharedInstance().currentUser!.profile.email) )")
}else{
print("[GSIN] Successful sign-in!")
}
self.signedIn = true
}
}
and finally the login :
struct w_splash: View {
let screenBounds:CGRect = UIScreen.main.bounds
var body: some View {
ZStack {
Image("logo").resizable()
.aspectRatio(contentMode: .fit)
.frame(width: screenBounds.width * 0.5, height: screenBounds.height * 0.2)
VStack {
Spacer()
HStack {
Button(action: {
test_app.gd.signIn()
}, label: {
HStack{
Image("btn_google_dark_normal_ios").resizable().frame(width: 50, height: 50, alignment: .center)
Text("Sign in with Google")
.font( Font.custom("Roboto-Medium", size: 14) )
.frame(width: .none,
height: 50,
alignment: .center)
.foregroundColor(Color.white)
.padding(.trailing, 30)
.padding(.leading, 10)
}
})
.isHidden(test_app.gd.signedIn)
.background(Color(hex: "#4285F4"))
.cornerRadius(5.5)
.padding(.bottom , screenBounds.height * 0.1)
.frame(width: screenBounds.width * 0.9,
height: 50,
alignment: .center)
.shadow(color: Color.black.opacity(0.2),
radius: 3,
x: 3,
y: 3)
}
}
}.onAppear{
if (test_app.gd.signedIn ){
print("user logged in test print out")
}
}
}
}
struct w_splash_Previews: PreviewProvider {
static var previews: some View {
w_splash()
}
}
I am still new with swiftUI, any ideas why I can't observe the variable?

Answer 1

It looks like you wanted to make GoogleDelegate a singleton.
I suggest you create a static instance of GoogleDelegate:
class GoogleDelegate: NSObject, GIDSignInDelegate, ObservableObject {
static let shared = GoogleDelegate()
#Published var signedIn: Bool = false
...
}
Then, in your views replace:
#ObservedObject static var gd = GoogleDelegate()
with:
#ObservedObject var gd = GoogleDelegate.shared
Also, note that you don't observe GoogleDelegate in your w_splash view, so you need to add it there as well:
struct w_splash: View {
#ObservedObject var gd = GoogleDelegate.shared
and refer directly to it using gd.signedIn (not test_app.gd.signedIn).
If you want to print something when gd.signedIn changes, you can use onChange:
.onChange(of: gd.signedIn) { signedIn in
print("signedIn: \(String(signedIn))")
}