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Description:

custom will pop scope

CustomWillPopScope #

Note: This package can be used on any platform, and is not specific to iOS.

CustomWillPopScope #
When using this widget, be sure to update canReturn based on the state of your screen, and only set it to false when the screen should not be allowed to pop. Additionally, the onWillPop property should not be changed once set.

A working app using this package can be found in the example folder.
Usage #
To use this package, add custom_will_pop_scope as a dependency in your pubspec.yaml file.
Example #
Import the library #

// main.dart
import 'package:decorated_icon/custom_will_pop_scope.dart';

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Wrap your screen #
Using the included CustomWillPopScope widget, wrap your screen and define an onWillPop callback for it, and onPopAction if you have a function to call when the screen pops (Like removing a route name in the example ).

Note that onWillPop should always return a bool. See the Flutter Docs for more.

The first Screen:

// first_screen.dart
class HomeScreen extends StatelessWidget {
void navigateToNext() {
locator<NavigationService>().navigateTo(secondScreen);
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar:AppBar(title: Text('CustomWillPopScopeDemo')),
body: Center(
child: ElevatedButton(
onPressed: () => navigateToNext(),
child: Padding(
padding: EdgeInsets.symmetric(horizontal: 24.0,vertical: 12.0),
child: Text('Go to second screen'),
),
),
),
);
}
}
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The second screen (Using CustomWillPopScope):

// second_screen.dart
class SecondScreen extends StatefulWidget {
@override
_SecondScreenState createState() => _SecondScreenState();
}

class _SecondScreenState extends State<SecondScreen> {

final NavigationService _navigationService = locator<NavigationService>();
/// Holds the state of the screen.
bool _canReturn = true;
/// Shows an alert and returns `false` when `_canReturn` is `true`.
/// This prevents the navigator from popping this route.
Future<bool> _onWillPop() async {
if (!_canReturn) {
// Show an alert before returning `false`.
showDialog(context: context,
builder: (context) => AlertDialog(
content: Text('Back navigation is disabled.'),
),
);
// Return `false` to prevent the route from popping.
return false;
} else {
_navigationService.removeLastRouteName();
return true;
}
}

void _onPopAction() {
_navigationService.removeLastRouteName();
}

/// Updates `_hasChanges` with the provided value.
void _updateChanges(bool value) => setState(() => _canReturn = value);

@override
Widget build(BuildContext context) {
return CustomWillPopScope(
// canReturn is optional, it is set to true by default
canReturn: _canReturn,
onWillPop: _onWillPop,
onPopAction: _onPopAction,
child: Scaffold(
appBar: AppBar(title: Text('Second Screen')),
body: Center(
child: Container(
decoration: BoxDecoration(
border: Border.all(color: _color),
borderRadius: BorderRadius.circular(6.0),
),
margin: EdgeInsets.symmetric(horizontal: 12.0),
child: SwitchListTile(
activeColor: _color,
onChanged: _updateChanges,
title: Text('Enable back navigation'),
value: _canReturn,
),
),
),
),
);
}
}

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