How to send arguments in restorablePush? (flutter) - flutter

Question

The flutter docs on restorablePush says that "Any object that is serializable via the StandardMessageCodec can be passed as arguments. Often, a Map is used to pass key-value pairs." But I am struggling to do this, as the route builder needs to be static.
I've made a small example below that illustrates the problem - basically, I want to be able to pass title as an argument from Screen1 to Screen2 and display it in the AppBar. Not sure where and how to put the argument in.
class Screen1 extends StatefulWidget {
const Screen1({Key? key}) : super(key: key);
#override
State<Screen1> createState() => _Screen1State();
}
class _Screen1State extends State<Screen1> {
String title = 'blah';
static Route<void> _myRouteBuilder(BuildContext context, Object? arguments) {
return MaterialPageRoute<void>(
builder: (BuildContext context) => const Screen2(),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: TextButton(
onPressed: () {
Navigator.restorablePush(context, _myRouteBuilder);
// Put somewhere... arguments: {'appBarTitle': title}
},
child: const Text('Go to Screen 2')),
),
);
}
}
class Screen2 extends StatefulWidget {
const Screen2({Key? key}) : super(key: key);
#override
State<Screen2> createState() => _Screen2State();
}
class _Screen2State extends State<Screen2> {
String _string = '';
#override
Widget build(BuildContext context) {
final args =
ModalRoute.of(context)!.settings.arguments as Map<String, String>;
_string = args['appBarTitle'] ?? 'error';
return Scaffold(
appBar: AppBar(title: Text(_string)),
);
}
}

Answer 1

You need to add the settings parameter to MaterialPageRoute so that ModalRoute receives the argument on screen 2.
class Screen1 extends StatefulWidget {
const Screen1({Key? key}) : super(key: key);
#override
State<Screen1> createState() => _Screen1State();
}
class _Screen1State extends State<Screen1> {
String title = 'blah';
static Route<void> _myRouteBuilder(BuildContext context, Object? arguments) {
return MaterialPageRoute<void>(
settings: RouteSettings(name: '/screen2', arguments: arguments),
builder: (BuildContext context) => const Screen2(),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: TextButton(
onPressed: () {
Navigator.restorablePush(context, _myRouteBuilder, arguments: {'appBarTitle': title});
// Put somewhere... arguments: {'appBarTitle': title}
},
child: const Text('Go to Screen 2')),
),
);
}
}
class Screen2 extends StatefulWidget {
const Screen2({Key? key}) : super(key: key);
#override
State<Screen2> createState() => _Screen2State();
}
class _Screen2State extends State<Screen2> {
String _string = 'Test';
#override
Widget build(BuildContext context) {
final args =
ModalRoute.of(context)?.settings.arguments;
if(args is Map){
_string = args['appBarTitle'] ?? 'error';
}
return Scaffold(
appBar: AppBar(title: Text(_string)),
);
}
}