showDialog sample

main.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:bloc/bloc.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  final _dialogBloc = DialogBloc();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Demo'),
      ),
      body: BlocBuilder(
        bloc: _dialogBloc,
        builder: (BuildContext context, DialogState state) {
          if (state is DialogVisible) {
            SchedulerBinding.instance.addPostFrameCallback((_) {
              showDialog(
                context: context,
                barrierDismissible: false,
                builder: (_) {
                  return Scaffold(
                    body: Center(
                      child: RaisedButton(
                        child: Text('dismiss'),
                        onPressed: () {
                          _dialogBloc.dispatch(HideDialog());
                        },
                      ),
                    ),
                  );
                },
              );
            });
          }
          if (state is DialogHidden) {
            SchedulerBinding.instance.addPostFrameCallback((_) {
              Navigator.pop(context);
            });
          }
          return Container(
            child: Center(
              child: Text('Dialog Sample'),
            ),
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.notifications),
        onPressed: () {
          _dialogBloc.dispatch(ShowDialog());
        },
      ),
    );
  }

  @override
  void dispose() {
    _dialogBloc.dispose();
    super.dispose();
  }
}

abstract class DialogEvent {}

class ShowDialog extends DialogEvent {}

class HideDialog extends DialogEvent {}

abstract class DialogState {}

class InitialDialogState extends DialogState {}

class DialogHidden extends DialogState {}

class DialogVisible extends DialogState {}


class DialogBloc extends Bloc<DialogEvent, DialogState> {
  @override
  DialogState get initialState => InitialDialogState();

  @override
  Stream<DialogState> mapEventToState(
    DialogState currentState,
    DialogEvent event,
  ) async* {
    if (event is ShowDialog) {
      yield DialogVisible();
    } else {
      yield DialogHidden();
    }
  }
}

i notice that the bloc show the dialog but when i inject the dialogclose event this don't dismiss the dialog.
Another think that i notice is when i use bloclistener the dialog just show once.
See bloc delegate transition