Thanks for your inspiration @lolgear! As you suggested I moved the @States into a model class and got it working this way. My code looks now like this, it is still work in progress and somewhat simpler than the code from your GitHub example. I post it here so others with similar problems get an idea how to get things working:
//
// RegistrationView.swift
//
// Created by Lars Sonchocky-Helldorf on 04.07.19.
// Copyright © 2019 Lars Sonchocky-Helldorf. All rights reserved.
//
import SwiftUI
import Combine
struct RegistrationView : View {
@ObjectBinding var registrationModel = RegistrationModel()
@State private var showAlert = false
@State private var alertTitle: String = ""
@State private var alertMessage: String = ""
@State private var registrationButtonDisabled = true
@State private var validatedEMail: String = ""
@State private var validatedPassword: String = ""
var body: some View {
Form {
Section {
TextField("Enter your EMail", text: $registrationModel.eMail)
SecureField("Enter a Password", text: $registrationModel.password)
SecureField("Enter the Password again", text: $registrationModel.passwordRepeat)
Button(action: registrationButtonAction) {
Text("Create Account")
}
.disabled($registrationButtonDisabled.value)
.presentation($showAlert) {
Alert(title: Text("\(alertTitle)"), message: Text("\(alertMessage)"))
}
.onReceive(self.registrationModel.validatedCredentials) { newValidatedCredentials in
self.registrationButtonDisabled = (newValidatedCredentials == nil)
}
}
Section {
Text("Validated EMail: \(validatedEMail)")
.onReceive(self.registrationModel.validatedEMail) { newValidatedEMail in
self.validatedEMail = newValidatedEMail != nil ? newValidatedEMail! : "EMail invalid"
}
Text("Validated Password: \(validatedPassword)")
.onReceive(self.registrationModel.validatedPassword) { newValidatedPassword in
self.validatedPassword = newValidatedPassword != nil ? newValidatedPassword! : "Passwords to short or don't matchst"
}
}
}
.navigationBarTitle(Text("Sign Up"))
}
func registrationButtonAction() {
let trimmedEMail: String = self.registrationModel.eMail.trimmingCharacters(in: .whitespaces)
if (trimmedEMail != "" && self.registrationModel.password != "") {
NetworkManager.sharedInstance.registerUser(NetworkManager.RegisterRequest(uid: trimmedEMail, password: self.registrationModel.password)) { (status) in
if status == 200 {
self.showAlert = true
self.alertTitle = NSLocalizedString("Registration successful", comment: "")
self.alertMessage = NSLocalizedString("please verify your email and login", comment: "")
} else if status == 400 {
self.showAlert = true
self.alertTitle = NSLocalizedString("Registration Error", comment: "")
self.alertMessage = NSLocalizedString("already registered", comment: "")
} else {
self.showAlert = true
self.alertTitle = NSLocalizedString("Registration Error", comment: "")
self.alertMessage = NSLocalizedString("network or app error", comment: "")
}
}
} else {
self.showAlert = true
self.alertTitle = NSLocalizedString("Registration Error", comment: "")
self.alertMessage = NSLocalizedString("username / password empty", comment: "")
}
}
}
class RegistrationModel : BindableObject {
@Published var eMail: String = ""
@Published var password: String = ""
@Published var passwordRepeat: String = ""
public var didChange = PassthroughSubject<Void, Never>()
var validatedEMail: AnyPublisher<String?, Never> {
return $eMail
.debounce(for: 0.5, scheduler: RunLoop.main)
.removeDuplicates()
.flatMap { username in
return Future { promise in
self.usernameAvailable(username) { available in
promise(.success(available ? username : nil))
}
}
}
.eraseToAnyPublisher()
}
var validatedPassword: AnyPublisher<String?, Never> {
return Publishers.CombineLatest($password, $passwordRepeat)
.debounce(for: 0.5, scheduler: RunLoop.main)
.map { password, passwordRepeat in
guard password == passwordRepeat, password.count > 5 else { return nil }
return password
}
.eraseToAnyPublisher()
}
var validatedCredentials: AnyPublisher<(String, String)?, Never> {
return Publishers.CombineLatest(validatedEMail, validatedPassword)
.map { validatedEMail, validatedPassword in
guard let eMail = validatedEMail, let password = validatedPassword else { return nil }
return (eMail, password)
}
.eraseToAnyPublisher()
}
func usernameAvailable(_ username: String, completion: (Bool) -> Void) {
let isValidEMailAddress: Bool = NSPredicate(format:"SELF MATCHES %@", "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}").evaluate(with: username)
completion(isValidEMailAddress)
}
}
#if DEBUG
struct RegistrationView_Previews : PreviewProvider {
static var previews: some View {
RegistrationView()
}
}
#endif
Update: I updated the code, got the password validation working (there were subtle mistakes in the code presented at the WWDC session (missing Publishers. before CombineLatest and missing .map after CombineLatest) but now the third publisher validatedCredentials never fires. I did set breakpoints in the lines with the guard in both validatedPassword and validatedCredentials, the one in validatedPassword was reached just fine but the one in validatedCredentials was never reached.
What is going on here?
