custom_will_pop_scope 2.1.1

Enables 'onWillPop' callbacks on Cupertino page transitions and improves visual feedback of rejected "Swipe to go back" gestures.

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';

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'),
            ),
          ),
        ),
      );
    }
}

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,
            ),
          ),
        ),
      ),
    );
  }
}