Navigator pass arguments with pushNamed

Might have been asked before but I can't find it but how do you pass a arguments to a named route?

This is how I build my routes

Widget build(BuildContext context) {
    return new Navigator(
      initialRoute: 'home/chooseroom',
      onGenerateRoute: (RouteSettings settings) {
        WidgetBuilder builder;
        switch (settings.name) {
          case 'home/chooseroom':
            // navigates to 'signup/choose_credentials'.
            builder = (BuildContext _) => new ChoosePage();
            break;
          case 'home/createpage':
            builder = (BuildContext _) => new CreateRoomPage();
            break;
          case 'home/presentation':
            builder = (BuildContext _) => new Presentation();
            break;
          default:
            throw new Exception('Invalid route: ${settings.name}');
        }
        return new MaterialPageRoute(builder: builder, settings: settings);
      },
    );

This is how you call it Navigator.of(context).pushNamed('home/presentation')

But what if my widget is new Presentation(arg1, arg2, arg3)?

No need for onGenerateRoute. Simply use

var exampleArgument = 'example string';

Navigator.pushNamed(
    context,
    '/otherscreen',
    arguments: {'exampleArgument': exampleArgument},
);

and extract the arguments as follows:

@override
Widget build(BuildContext context) {
    final arguments = (ModalRoute.of(context)?.settings.arguments ?? <String, dynamic>{}) as Map;

    print(arguments['exampleArgument']);

    return Scaffold(...);
}

pushNamed() now supports arguments as of this merged pull request. If you can't wait, switch to channel master (flutter channel master and probably followed by flutter upgrade).

How to send:

    Navigator.pushNamed(ctx, '/foo', arguments: someObject);

How to receive:

...
    return MaterialApp(
        ...
        onGenerateRoute: _getRoute,
        ...
    );
...

Route<dynamic> _getRoute(RouteSettings settings) {
    if (settings.name == '/foo') {
        // FooRoute constructor expects SomeObject
        return _buildRoute(settings, new FooRoute(settings.arguments));
    }

    return null;
}

MaterialPageRoute _buildRoute(RouteSettings settings, Widget builder) {
    return new MaterialPageRoute(
        settings: settings,
        builder: (ctx) => builder,
    );
}

The "arguments" can be any object, e.g. a map.

Arguments can be any object, you can make an array as you can see:

Navigator.of(context).pushNamed('/upload', arguments: {'_imagePath':_imagePath,
      'num_docfiscal':num_docfiscal,'dta_docfiscal':dta_docfiscal});

and access to the router class.