diegoveloper.dart

import 'package:flutter/material.dart';
import 'package:flutter_colombia/main.dart';

class _DiegoveloperX {
  final navigatorKey = GlobalKey<NavigatorState>();

  void showMyCustomDialog(Widget widget) {
    showDialog(
      context: navigatorKey.currentContext,
      builder: (_) => AlertDialog(
        content: widget,
      ),
    );
  }

  void navigateTo(MyNewWidget myNewWidget) {
    navigatorKey.currentState.push(MaterialPageRoute(
      builder: (_) => myNewWidget,
    ));
  }

  void pop() {
    navigatorKey.currentState.pop();
  }
}

// ignore: non_constant_identifier_names
final DiegoveloperX = _DiegoveloperX();

home_bloc.dart

import 'package:flutter/material.dart';

class HomeBloc extends ChangeNotifier {
  int counter = 0;

  void increment() {
    counter++;
    notifyListeners();
  }

  void decrement() {
    counter--;
    notifyListeners();
  }
}

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_colombia/diegoveloper.dart';

import 'home_bloc.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      navigatorKey: DiegoveloperX.navigatorKey,
      theme: ThemeData.dark(),
      home: HomeWidget(),
    );
  }
}

class HomeWidget extends StatelessWidget {
  final bloc = HomeBloc();

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
        animation: bloc,
        builder: (context, _) {
          return Scaffold(
            appBar: AppBar(
              actions: [
                IconButton(
                  icon: Icon(Icons.remove_from_queue),
                  onPressed: () {
                    DiegoveloperX.showMyCustomDialog(
                      Text('Hello Colombia'),
                    );
                  },
                ),
                IconButton(
                  icon: Icon(Icons.pages),
                  onPressed: () {
                    DiegoveloperX.navigateTo(MyNewWidget());
                  },
                ),
              ],
            ),
            body: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Expanded(
                  child: Container(
                    color: Colors.blue,
                    alignment: Alignment.center,
                    child: Text(
                      bloc.counter.toString(),
                      style: TextStyle(
                        fontWeight: FontWeight.bold,
                        fontSize: 90,
                      ),
                    ),
                  ),
                ),
                Expanded(
                  child: Container(
                    color: Colors.green,
                    child: Row(
                      mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                      children: [
                        Expanded(
                          child: RaisedButton(
                            child: Icon(
                              Icons.add,
                              size: 100,
                            ),
                            onPressed: () {
                              bloc.increment();
                            },
                          ),
                        ),
                        const SizedBox(width: 10),
                        Expanded(
                          child: RaisedButton(
                            child: Icon(
                              Icons.remove,
                              size: 100,
                            ),
                            onPressed: () {
                              bloc.decrement();
                            },
                          ),
                        ),
                      ],
                    ),
                  ),
                ),
              ],
            ),
          );
        });
  }
}

class MyNewWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        actions: [
          IconButton(
            icon: Icon(Icons.backspace),
            onPressed: () {
              DiegoveloperX.pop();
            },
          ),
        ],
      ),
    );
  }
}