Flutter Firebase Sign In With Apple Not Working ios - ios

Question

I am trying to set up with apple sign in with the following code. When tapping the button nothing happens.
I get the following error:
NoSuchMethodError (NoSuchMethodError: The method '[]' was called on null.
Receiver: null
Tried calling: []("User"))
The new user appears in firebase authentication but other than that the app does not work.
I have enabled sign in with apple in xcode and on developer.apple.com. I have also tried redownloading my provisioning profiles in xcode but no luck.
I have enabled apple sign in in firebase.
Does anyone know how to fix this?
mixin AuthenticationApple {
static String generateNonce([int length = 32]) {
const charset =
'0123456789ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz-._';
final random = Random.secure();
return List.generate(length, (_) => charset[random.nextInt(charset.length)])
.join();
}
/// Returns the sha256 hash of [input] in hex notation.
static String sha256ofString(String input) {
final bytes = utf8.encode(input);
final digest = sha256.convert(bytes);
return digest.toString();
}
static Future<User> signInWithApple({BuildContext context}) async {
User user;
// To prevent replay attacks with the credential returned from Apple, we
// include a nonce in the credential request. When signing in with
// Firebase, the nonce in the id token returned by Apple, is expected to
// match the sha256 hash of `rawNonce`.
final rawNonce = generateNonce();
final nonce = sha256ofString(rawNonce);
// Request credential for the currently signed in Apple account.
final appleCredential = await SignInWithApple.getAppleIDCredential(
scopes: [
AppleIDAuthorizationScopes.email,
AppleIDAuthorizationScopes.fullName,
],
nonce: nonce,
);
// Create an `OAuthCredential` from the credential returned by Apple.
final oauthCredential = OAuthProvider('apple.com').credential(
idToken: appleCredential.identityToken,
rawNonce: rawNonce,
);
try {
// Sign in the user with Firebase. If the nonce we generated earlier does
// not match the nonce in `appleCredential.identityToken`, sign in will fail.
final UserCredential userCredential =
await FirebaseAuth.instance.signInWithCredential(oauthCredential);
user = userCredential.user;
} on FirebaseAuthException catch (e) {
if (e.code == 'account-exists-with-different-credential') {
ScaffoldMessenger.of(context).showSnackBar(
AppWidget.customSnackBar(
content: 'The account already exists with a different credential.',
),
);
} else if (e.code == 'invalid-credential') {
ScaffoldMessenger.of(context).showSnackBar(
AppWidget.customSnackBar(
content: 'Error occurred while accessing credentials. Try again.',
),
);
}
} catch (e) {
ScaffoldMessenger.of(context).showSnackBar(
AppWidget.customSnackBar(
content: 'Error occurred using Apple Sign-In. Try again.',
),
);
}
return user;
}
}

Answer 1

I just surpassed this issue by using iOS 13.0 for simulator. It seems there's an issue with higher versions when using the simulator but not with physical devices.
You can download and install simulators all the way back to iOS 13.0 (which is the minimum version for Apple Sign-In. In Xcode:
Xcode > Preferences.
Select the "Components" tab.
Mark the simulators you want.
Press "Check and Install Now".