Add Sign in with Apple login page

sample-native-app.xcodeproj/project.pbxproj

@@ -251,6 +251,7 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CODE_SIGN_ENTITLEMENTS = "sample-native-app/sample-native-app.entitlements";
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
 				DEVELOPMENT_TEAM = VMBY3VYW4U;
@@ -284,6 +285,7 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CODE_SIGN_ENTITLEMENTS = "sample-native-app/sample-native-app.entitlements";
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
 				DEVELOPMENT_TEAM = VMBY3VYW4U;

sample-native-app/ContentView.swift

@@ -8,17 +8,108 @@
 import SwiftUI
 
 struct ContentView: View {
+    @State private var signedInUser: AppleIDCredential?
+    @State private var errorMessage: String?
+
+    var body: some View {
+        Group {
+            if let user = signedInUser {
+                SignedInView(user: user) {
+                    signedInUser = nil
+                }
+            } else {
+                LoginView(
+                    onSignIn: { credential in
+                        errorMessage = nil
+                        signedInUser = credential
+                    },
+                    onFailure: { error in
+                        let message = error.localizedDescription
+                        errorMessage = message
+                        Task { @MainActor in
+                            try? await Task.sleep(for: .seconds(4))
+                            if errorMessage == message {
+                                errorMessage = nil
+                            }
+                        }
+                    },
+                    onRequest: {
+                        errorMessage = nil
+                    }
+                )
+                .overlay(alignment: .top) {
+                    if let errorMessage {
+                        Text(errorMessage)
+                            .font(.footnote)
+                            .foregroundStyle(.white)
+                            .padding(.horizontal, 16)
+                            .padding(.vertical, 8)
+                            .background(.red.opacity(0.85), in: Capsule())
+                            .padding(.top, 24)
+                            .accessibilityIdentifier("loginErrorBanner")
+                    }
+                }
+            }
+        }
+        .animation(.easeInOut, value: signedInUser)
+    }
+}
+
+struct SignedInView: View {
+    let user: AppleIDCredential
+    var onSignOut: () -> Void
+
     var body: some View {
-        VStack {
-            Image(systemName: "globe")
-                .imageScale(.large)
-                .foregroundStyle(.tint)
-            Text("Hello, world!")
+        VStack(spacing: 24) {
+            Image(systemName: "checkmark.seal.fill")
+                .resizable()
+                .scaledToFit()
+                .frame(width: 72, height: 72)
+                .foregroundStyle(.green)
+
+            Text("Signed in")
+                .font(.title.weight(.semibold))
+
+            VStack(spacing: 8) {
+                Text(user.displayName)
+                    .font(.headline)
+                if let email = user.email, !email.isEmpty {
+                    Text(email)
+                        .font(.subheadline)
+                        .foregroundStyle(.secondary)
+                }
+                Text("User ID: \(user.userIdentifier)")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                    .lineLimit(1)
+                    .truncationMode(.middle)
+                    .padding(.horizontal, 24)
+            }
+
+            Button("Sign out", action: onSignOut)
+                .buttonStyle(.borderedProminent)
+                .accessibilityIdentifier("signOutButton")
         }
         .padding()
     }
 }
 
-#Preview {
+#Preview("Login") {
     ContentView()
 }
+
+#Preview("Signed in") {
+    SignedInView(
+        user: AppleIDCredential(
+            userIdentifier: "001234.abcdef.5678",
+            email: "jane@example.com",
+            fullName: {
+                var components = PersonNameComponents()
+                components.givenName = "Jane"
+                components.familyName = "Appleseed"
+                return components
+            }()
+        ),
+        onSignOut: {}
+    )
+}

sample-native-app/LoginView.swift

@@ -0,0 +1,127 @@
+//
+//  LoginView.swift
+//  sample-native-app
+//
+
+import AuthenticationServices
+import SwiftUI
+
+struct LoginView: View {
+    @Environment(\.colorScheme) private var colorScheme
+
+    var onSignIn: (AppleIDCredential) -> Void
+    var onFailure: (Error) -> Void
+    var onRequest: () -> Void = {}
+
+    var body: some View {
+        ZStack {
+            LinearGradient(
+                colors: [
+                    Color(red: 0.06, green: 0.07, blue: 0.12),
+                    Color(red: 0.12, green: 0.13, blue: 0.22),
+                ],
+                startPoint: .topLeading,
+                endPoint: .bottomTrailing
+            )
+            .ignoresSafeArea()
+
+            VStack(spacing: 32) {
+                Spacer()
+
+                VStack(spacing: 16) {
+                    Image(systemName: "applelogo")
+                        .resizable()
+                        .scaledToFit()
+                        .frame(width: 64, height: 64)
+                        .foregroundStyle(.white)
+                        .accessibilityHidden(true)
+
+                    Text("Welcome")
+                        .font(.largeTitle.weight(.bold))
+                        .foregroundStyle(.white)
+
+                    Text("Sign in to continue to Sample App")
+                        .font(.body)
+                        .multilineTextAlignment(.center)
+                        .foregroundStyle(.white.opacity(0.75))
+                        .padding(.horizontal, 32)
+                }
+
+                Spacer()
+
+                VStack(spacing: 16) {
+                    SignInWithAppleButton(
+                        .signIn,
+                        onRequest: { request in
+                            request.requestedScopes = [.fullName, .email]
+                            onRequest()
+                        },
+                        onCompletion: { result in
+                            switch result {
+                            case .success(let authorization):
+                                if let credential = authorization.credential as? ASAuthorizationAppleIDCredential {
+                                    onSignIn(AppleIDCredential(credential: credential))
+                                }
+                            case .failure(let error):
+                                if let authError = error as? ASAuthorizationError {
+                                    switch authError.code {
+                                    case .canceled, .unknown:
+                                        return
+                                    default:
+                                        break
+                                    }
+                                }
+                                onFailure(error)
+                            }
+                        }
+                    )
+                    .signInWithAppleButtonStyle(colorScheme == .dark ? .white : .black)
+                    .frame(height: 52)
+                    .clipShape(RoundedRectangle(cornerRadius: 12, style: .continuous))
+                    .accessibilityIdentifier("signInWithAppleButton")
+
+                    Text("By continuing you agree to our Terms and Privacy Policy.")
+                        .font(.footnote)
+                        .multilineTextAlignment(.center)
+                        .foregroundStyle(.white.opacity(0.6))
+                        .padding(.horizontal, 24)
+                }
+                .padding(.horizontal, 24)
+                .padding(.bottom, 24)
+            }
+            .safeAreaPadding(.bottom, 24)
+        }
+    }
+}
+
+struct AppleIDCredential: Equatable {
+    let userIdentifier: String
+    let email: String?
+    let fullName: PersonNameComponents?
+
+    init(credential: ASAuthorizationAppleIDCredential) {
+        self.userIdentifier = credential.user
+        self.email = credential.email
+        self.fullName = credential.fullName
+    }
+
+    init(userIdentifier: String, email: String?, fullName: PersonNameComponents?) {
+        self.userIdentifier = userIdentifier
+        self.email = email
+        self.fullName = fullName
+    }
+
+    var displayName: String {
+        if let fullName, let formatted = PersonNameComponentsFormatter().string(for: fullName), !formatted.isEmpty {
+            return formatted
+        }
+        if let email, !email.isEmpty {
+            return email
+        }
+        return "Apple User"
+    }
+}
+
+#Preview {
+    LoginView(onSignIn: { _ in }, onFailure: { _ in })
+}

sample-native-app/sample-native-app.entitlements

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.developer.applesignin</key>
+	<array>
+		<string>Default</string>
+	</array>
+</dict>
+</plist>