How use appleID signin in flutter?

I used sign_in_with_apple: ^4.3.0 package to appleID signin this is the latest version for the appleID signin

I couldn't find any documentations how to use this version without package example code. referring that example I tried a code

  Future<void> signInWithApple() async {
    try {
      final credential = await SignInWithApple.getAppleIDCredential(
          scopes: [
            AppleIDAuthorizationScopes.email,
            AppleIDAuthorizationScopes.fullName,
          ]);

      // Get the OAuth token and ID Token
      final AuthCredential authCredential =
      OAuthProvider("apple.com").credential(
          accessToken: String.fromCharCodes(credential.authorizationCode),
          idToken: String.fromCharCodes(credential.identityToken));

      // Signing in to firebase user instance
      final UserCredential userCredential =
      await FirebaseAuth.instance.signInWithCredential(authCredential);

      // Update the user properties in the provider
      _email = userCredential.user?.email;
      _uid = userCredential.user?.uid;
      _displayName = userCredential.user?.displayName;

      notifyListeners();
    } catch (e) {
      // Handle the error
      print(e);
      _hasError = true;
      _errorCode = e.toString();
      notifyListeners();
    }
  }

in this code show these errors..

how to resolve these errors and signin to app using appleID

You can't use String.fromCharCodes on a String value, also credential.authorizationCode and credential.identityToken are String values so you don't have to convert them.

Try to replace this

OAuthProvider("apple.com").credential(
      accessToken: String.fromCharCodes(credential.authorizationCode),
      idToken: String.fromCharCodes(credential.identityToken));  

with this

OAuthProvider("apple.com").credential(
      accessToken: credential.authorizationCode,
      idToken: credential.identityToken);