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// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This sample demonstrates showing a confirmation dialog before navigating
// away from a page.
import 'package:flutter/material.dart';
void main() => runApp(const NavigatorPopHandlerApp());
class NavigatorPopHandlerApp extends StatelessWidget {
const NavigatorPopHandlerApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
initialRoute: '/home',
routes: <String, WidgetBuilder>{
'/home': (BuildContext context) => const _HomePage(),
'/two': (BuildContext context) => const _PageTwo(),
},
);
}
}
class _HomePage extends StatefulWidget {
const _HomePage();
@override
State<_HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<_HomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text('Page One'),
TextButton(
onPressed: () {
Navigator.of(context).pushNamed('/two');
},
child: const Text('Next page'),
),
],
),
),
);
}
}
class _PageTwo extends StatefulWidget {
const _PageTwo();
@override
State<_PageTwo> createState() => _PageTwoState();
}
class _PageTwoState extends State<_PageTwo> {
/// Shows a dialog and resolves to true when the user has indicated that they
/// want to pop.
///
/// A return value of null indicates a desire not to pop, such as when the
/// user has dismissed the modal without tapping a button.
Future<bool?> _showBackDialog() {
return showDialog<bool>(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Are you sure?'),
content: const Text(
'Are you sure you want to leave this page?',
),
actions: <Widget>[
TextButton(
style: TextButton.styleFrom(
textStyle: Theme.of(context).textTheme.labelLarge,
),
child: const Text('Nevermind'),
onPressed: () {
Navigator.pop(context, false);
},
),
TextButton(
style: TextButton.styleFrom(
textStyle: Theme.of(context).textTheme.labelLarge,
),
child: const Text('Leave'),
onPressed: () {
Navigator.pop(context, true);
},
),
],
);
},
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text('Page Two'),
PopScope(
canPop: false,
onPopInvoked: (bool didPop) async {
if (didPop) {
return;
}
final bool shouldPop = await _showBackDialog() ?? false;
if (context.mounted && shouldPop) {
Navigator.pop(context);
}
},
child: TextButton(
onPressed: () async {
final bool shouldPop = await _showBackDialog() ?? false;
if (context.mounted && shouldPop) {
Navigator.pop(context);
}
},
child: const Text('Go back'),
),
),
],
),
),
);
}
}