How to catch exception in flutter?

Let's say this is your function which throws an exception:

Future<void> foo() async {
  throw Exception('FooException');
}

You can either use try-catch block or catchError on the Future since both do the same thing.

• Using try-catch

  try {
    await foo();
  } on Exception catch (e) {
    print(e); // Only catches an exception of type `Exception`.
  } catch (e) {
    print(e); // Catches all types of `Exception` and `Error`.
  }
  

• Use catchError

  await foo().catchError(print);
  

Try

void loginUser(String email, String password) async {
  try {
    var user = await _data
      .userLogin(email, password);
    _view.onLoginComplete(user);
      });
  } on FetchDataException catch(e) {
    print('error caught: $e');
    _view.onLoginError();
  }
}

catchError is sometimes a bit tricky to get right. With async/await you can use try/catch like with sync code and it is usually much easier to get right.

I was trying to find this answer when got to this page, hope it helps: https://stackoverflow.com/a/57736915/12647239

Basicly i was just trying to catch an error message from a method, but i was calling

throw Exception("message")

And in "catchError" i was getting "Exception: message" instead of "message".

catchError(
  (error) => print(error)
);

fixed with the return in the above reference