NoSuchMethodError: Class 'FlutterError' has no instance getter 'code'. Receiver: Instance of 'FlutterError' Tried calling: code)

Question

I've been trying a sample Flutter application code from GitHub to simply login and register the user on Firebase. Every time I login or register after clean building the application, it takes me to the main page but throws this exception Exception has occurred. NoSuchMethodError (NoSuchMethodError: Class 'FlutterError' has no instance getter 'code'. Receiver: Instance of 'FlutterError' Tried calling: code) I've no idea what 'FlutterError' is referring to because I don't see any such class. and there are two occurrences of code in the file named 'login-register.dart'. I'm attaching the code below: (Note: it runs okay after I hot reload the app and the user is already logged in, only throws exception the first time)

void _validateLoginInput() async {
      final FormState form = _formKey.currentState;
      if (_formKey.currentState.validate()) {
        form.save();
        _sheetController.setState(() {
          _loading = true;
        });
        try {
          final FirebaseUser user = (await FirebaseAuth.instance
              .signInWithEmailAndPassword(email: _email, password: _password)).user;
          // final uid = user.uid;
          Navigator.of(context).pushReplacementNamed('/home');
        } catch (error) {
          switch (error.code) {
            case "ERROR_USER_NOT_FOUND":
              {
                _sheetController.setState(() {
                  errorMsg =
                      "There is no user with such entries. Please try again.";

                  _loading = false;
                });
                showDialog(
                    context: context,
                    builder: (BuildContext context) {
                      return AlertDialog(
                        content: Container(
                          child: Text(errorMsg),
                        ),
                      );
                    });
              }
              break;
            case "ERROR_WRONG_PASSWORD":
              {
                _sheetController.setState(() {
                  errorMsg = "Password doesn\'t match your email.";
                  _loading = false;
                });
                showDialog(
                    context: context,
                    builder: (BuildContext context) {
                      return AlertDialog(
                        content: Container(
                          child: Text(errorMsg),
                        ),
                      );
                    });
              }
              break;
            default:
              {
                _sheetController.setState(() {
                  errorMsg = "";
                });
              }
          }
        }
      } else {
        setState(() {
          _autoValidate = true;
        });
      }
    }

void _validateRegisterInput() async {
      final FormState form = _formKey.currentState;
      if (_formKey.currentState.validate()) {
        form.save();
        _sheetController.setState(() {
          _loading = true;
        });
        try {
          final FirebaseUser user = (await FirebaseAuth.instance
              .createUserWithEmailAndPassword(
                  email: _email, password: _password)).user;
          UserUpdateInfo userUpdateInfo = new UserUpdateInfo();
          userUpdateInfo.displayName = _displayName;
          user.updateProfile(userUpdateInfo).then((onValue) {
            Navigator.of(context).pushReplacementNamed('/home');
            Firestore.instance.collection('users').document().setData(
                {'email': _email, 'displayName': _displayName}).then((onValue) {
              _sheetController.setState(() {
                _loading = false;
              });
            });
          });
        } catch (error) {
          switch (error.code) {
            case "ERROR_EMAIL_ALREADY_IN_USE":
              {
                _sheetController.setState(() {
                  errorMsg = "This email is already in use.";
                  _loading = false;
                });
                showDialog(
                    context: context,
                    builder: (BuildContext context) {
                      return AlertDialog(
                        content: Container(
                          child: Text(errorMsg),
                        ),
                      );
                    });
              }
              break;
            case "ERROR_WEAK_PASSWORD":
              {
                _sheetController.setState(() {
                  errorMsg = "The password must be 6 characters long or more.";
                  _loading = false;
                });
                showDialog(
                    context: context,
                    builder: (BuildContext context) {
                      return AlertDialog(
                        content: Container(
                          child: Text(errorMsg),
                        ),
                      );
                    });
              }
              break;
            default:
              {
                _sheetController.setState(() {
                  errorMsg = "";
                });
              }
          }
        }
      } else {
        setState(() {
          _autoValidate = true;
        });
      }
    }

Answer 1

The exception you're catching doesn't have a code property. That only exists with the firebase exception implementation, not the general exception class.

If you expect a certain type of error, you should explicitly catch that error and handle it properly and have a separate catch block for all other errors.

This can be done with an on ... catch block:

try {
  final FirebaseUser user = (await FirebaseAuth.instance
    .signInWithEmailAndPassword(email: _email, password: _password)).user;
  // final uid = user.uid;
  Navigator.of(context).pushReplacementNamed('/home');
} on FirebaseAuthException catch (error) {
  ...
} catch(e) {
  ...
}

The methods you're calling in the code you shared will throw FirebaseAuthExceptions as shown in the code above.