Abrupt transition between views within a Navigation View - firebase

Question

I'm having trouble figuring out how to smoothly navigate from my SignInView() to my FirstView(). I have my FirstView() inside of a Navigation Stack, but the transition between the views is very abrupt and devoid of the transition that you normally get with the use of a NavigationLink. How can I get the transition to work?
Much appreciated!
Here is the relevant code...
struct ContentView: View {
#EnvironmentObject var viewModel: AppViewModel
var body: some View {
VStack{
NavigationView {
if viewModel.signedIn {
FirstView()
.transition(.slide)
} else {
//.onAppear method is used for keyboard management (See Misc Functions...)
SignInView()
.onAppear(perform: UIApplication.shared.addTapGestureRecognizer)
.navigationBarHidden(true)
}
}
.onAppear {
viewModel.listen()
}
}
}
}
class AppViewModel: ObservableObject {
private var db = Firestore.firestore()
#Published var userInfo: User?
#Published var signedIn: Bool = false
var handle: AuthStateDidChangeListenerHandle?
let authRef = Auth.auth()
var authHandle : AuthStateDidChangeListenerHandle?
var rootInfoCollection : CollectionReference!
var userIdRef = ""
func fetchUserData(){
db.collection("Users").document("\(userIdRef)").getDocument { document, error in
// Check for error
if error == nil {
// Check that this document exists
if document != nil && document!.exists {
self.userInfo = document.map { (documentSnapshot) -> User in
let data = documentSnapshot.data()
let uid = data?["uid"] as? UUID ?? UUID()
let company = data?["company"] as? String ?? ""
let name = data?["name"] as? String ?? ""
let admin = data?["admin"] as? Bool ?? false
let photo = data?["photo"] as? String ?? ""
return User(uid: uid, company: company, name: name, admin: admin, photo: photo)
}
withAnimation {
self.signedIn = true
}
}
}
}
}
func listen(){
handle = authRef.addStateDidChangeListener({ auth, user in
print(user?.email ?? "No User Found")
if let user = auth.currentUser {
self.userIdRef = user.uid
self.rootInfoCollection = Firestore.firestore().collection("/Users/")
DispatchQueue.main.async {
self.fetchUserData()
}
} else {
self.signedIn = false
}
})
}
func signIn(email: String, password: String){
authRef.signIn(withEmail: email, password: password) { result, error in
guard result != nil, error == nil else {
return
}
}
}
}
struct SignInView: View {
#EnvironmentObject var viewModel: AppViewModel
#State private var username : String = ""
#State private var password : String = ""
#State private var shouldShowLoginAlert: Bool = false
#State var selectedImageArray : [Image] = []
var disableLoginButton : Bool {
return self.username.isEmpty || self.password.isEmpty
}
var body: some View {
VStack{
Image(uiImage: #imageLiteral(resourceName: "awText"))
.resizable()
.frame(width: 180, height: 100)
.padding(.bottom, 50)
TextField("Email", text: $username)
.padding(.leading)
.disableAutocorrection(true)
.autocapitalization(.none)
Rectangle().fill(Color.gray.opacity(0.25)).frame(height: 1, alignment: .center).padding(.bottom)
.padding(.bottom)
.onChange(of: self.username, perform: { value in
if value.count > 10 {
self.username = String(value.prefix(20)) //Max 10 Characters for Username.
}
})
SecureField("Password", text: $password)
.padding(.leading)
.disableAutocorrection(true)
.autocapitalization(.none)
Rectangle().fill(Color.gray.opacity(0.25)).frame(height: 1, alignment: .center)
.onChange(of: self.username, perform: { value in
if value.count > 10 {
self.username = String(value.prefix(10)) //Max 10 Characters for Password.
}
})
//SignIn Button
Button(action: {
viewModel.signIn(email: username, password: password)
}, label: {
Text("Sign In")
.disabled(disableLoginButton)
.frame(width: 300, height: 50)
.background(Color.green)
.clipShape(RoundedRectangle(cornerRadius: 20, style: .continuous))
.padding()
})
}

Answer 1

Replacing the default NavigationView behavior with your own animations isn't necessarily totally straightforward. I'll lay out one possibility, but another would be to use a real NavigationView transition, but just hide the back button once you're on FirstView.
To do the transition yourself, you'll need one root element to NavigationView, an if clause, a transition(.slide) and withAnimation. Here's a simplified version of your code showing just these elements:
class AppViewModel: ObservableObject {
#Published var signedIn = false
}
struct FirstView : View {
var body: some View {
Text("Signed in")
}
}
struct ContentView: View {
#StateObject var viewModel = AppViewModel()
var body: some View {
NavigationView {
VStack {
if viewModel.signedIn {
FirstView()
.transition(.slide)
} else {
Button("Sign me in") {
withAnimation {
viewModel.signedIn = true
}
}
}
}
.frame(maxWidth: .infinity, maxHeight: .infinity)
.navigationBarHidden(true)
}
}
}