import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MainPage(),
    );
  }
}

class MainPage extends StatefulWidget {
  const MainPage({Key key}) : super(key: key);

  @override
  _MainPageState createState() => _MainPageState();
}

class _MainPageState extends State<MainPage> {
  bool _confirmed;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text("Confirmation: $_confirmed"),
            SizedBox(height: 48),
            OutlineButton(
              onPressed: () async {
                bool confirmed = await showDialog<bool>(
                    context: context,
                    builder: (context) => ConfirmationDialog());

                setState(() {
                  _confirmed = confirmed;
                });
              },
              child: Text("Show Confirm Popup"),
            ),
          ],
        ),
      ),
    );
  }
}

class ConfirmationDialog extends StatelessWidget {
  const ConfirmationDialog({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: Text("confirm"),
      content: Text("Do you confirm"),
      actions: [
        TextButton(
            onPressed: () => Navigator.pop(context, true), child: Text("Yes")),
        TextButton(
            onPressed: () => Navigator.pop(context, false), child: Text("No")),
      ],
    );
  }
}