Passing Arguments between pages but show this error - flutter

Question

I m trying to pass arguments between pages but I m getting this error:
FlutterError (Could not find a generator for route RouteSettings("detail", Instance of 'Commodity') in the _WidgetsAppState.
Make sure your root app widget has provided a way to generate
this route.
Generators for routes are searched for in the following order:
For the "/" route, the "home" property, if non-null, is used.
Otherwise, the "routes" table is used, if it has an entry for the route.
Otherwise, onGenerateRoute is called. It should return a non-null value for any valid route not handled by "home" and "routes".
Finally if all else fails onUnknownRoute is called.
Unfortunately, onUnknownRoute was not set.)
I don't know why because 'detail' page already setted
This is my Main App
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
initialRoute: WelcomePage.routeName,
routes: {
'/welcome': (_) => const WelcomePage(),
'detail': (_) => SubCommoditiePage(),
},
);
}
}
This is my From Page
class DisplayOptions extends StatelessWidget {
final List<Commodity> _optionsToDisplay;
const DisplayOptions(this._optionsToDisplay);
#override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: _optionsToDisplay.length,
itemBuilder: (context, index) {
final opt = _optionsToDisplay[index];
return ListTile(
title: Text(opt.label),
subtitle: Text(opt.shortLabel),
onTap: () {
Navigator.pushNamed(context, 'detail', arguments: _optionsToDisplay[index]);
});
});
}
}
This is my Destination Page
class SubCommoditiePage extends StatefulWidget {
const SubCommoditiePage({Key? key}) : super(key: key);
static const String routenName = 'detail';
static Route route() {
return MaterialPageRoute(
builder: (_) => const SubCommoditiePage(),
settings: const RouteSettings(name: routenName));
}
#override
_SubCommoditiePageState createState() => _SubCommoditiePageState();
}
class _SubCommoditiePageState extends State<SubCommoditiePage> {
#override
Widget build(BuildContext context) {
final Commodity commoditySeleted =
ModalRoute.of(context)?.settings.arguments as Commodity;
return Scaffold(
appBar: AppBar(
title: Text(commoditySeleted.label),
),
);
}
}

Answer 1

For initial/homepage, use /. In this case your WelcomePage.routeName will be /;
and route
routes: {
WelcomePage.routeName: (_) => WelcomePage(),
..........
},
You don't need to pass initialRoute while the root '/' will be selected.
For more about named-routes

Answer 2

The way I was able to solve it was:
I evidently didn't know why flutter didn't recognize my 'detail' page.
And I had to do it this way:
This is my From Page
in my ontap, I used
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SubCommoditiePage(
seleted: _optionsToDisplay[index],
)));
like that:
class DisplayOptions extends StatelessWidget {
final List<Commodity> _optionsToDisplay;
const DisplayOptions(this._optionsToDisplay);
#override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: _optionsToDisplay.length,
itemBuilder: (context, index) {
final opt = _optionsToDisplay[index];
return ListTile(
title: Text(opt.label),
subtitle: Text(opt.shortLabel),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SubCommoditiePage(
seleted: _optionsToDisplay[index],
)));
});
});
}
}
adding to my page: final Commodity seleted; and with widget.selected... I was able to use it perfectly!
class SubCommoditiePage extends StatefulWidget {
final Commodity seleted;
const SubCommoditiePage({required this.seleted, Key? key}) : super(key: key);
static const String routenName = 'detail';
#override
_SubCommoditiePageState createState() => _SubCommoditiePageState();
}
class _SubCommoditiePageState extends State<SubCommoditiePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.seleted.label),
backgroundColor: const Color.fromRGBO(37, 59, 128, 5),
),
body: ListView.builder(
itemCount: widget.seleted.subCommodities.length,
itemBuilder: (context, index) {
final opt = widget.seleted.subCommodities[index];
return ListTile(
title: Text(opt.label),
onTap: () {},
);
}));
}
}