login_bloc.dart

import 'package:bloc/bloc.dart';

part 'login_event.dart';
part 'login_state.dart';

/*
  We extend the the Bloc class and also mention the
  type for event and state.
*/
class LoginBloc extends Bloc<LoginEvent, LoginState> {

  /*
  * 1. This is a constructor method of
  * the Bloc, incase of making API you will inject repository.

  * 2. We are passing the first event to the super class,
  * so, this is the first event that get emitted,
  * we can use it in the UI, to run some setup code.
  */
  LoginBloc() : super(LoginInitial()) {

    /*
    * 1. With this method we register event handle with event type,
    * In this case we are using Login Event,
    * as this Bloc, operates on LoginEvent and LoginState

    * 2. This method takes two parameters Handler and transformer,
    * Transformer for is a optional method, we are not using it here.
    */

    // Note: Every event should have only one handler
    on<LoginEvent>(_loginEventHandler);


    /*
    Will be used Later
    on<LoginButtonTappedEvent>(_loginButtonTapped);
    on<ShowSnackBarButtonTappedEvent>(_showSnackBarTapped);
    */
  }

  /*
  * 1. This method returns Future void, which indicates,
  * it is capable of performing async operations.

  * 2. It takes in two required parameter,
  * Event and a emitter
  */

  Future<void> _loginEventHandler(LoginEvent e, Emitter emit) async {

    // Perform some task run some business login

    /*
    * Emitter class have few other methods,
    * but we are using the most simple one
    * as we just need to emit an state.
    */
    emit(LoginInitial());
  }

  /*
  Will be used Later
  Future<void> _loginButtonTapped(LoginButtonTappedEvent e, Emitter emit) async {
    emit(UpdateTextState(text: "Text is sent from the Bloc"));
  }

  Future<void> _showSnackBarTapped(ShowSnackBarButtonTappedEvent e, Emitter emit) async {
    emit(ShowSnackbarState());
  }*/
}