Error stating: 1 positional argument(s) expected, but 0 found. Try adding the missing arguments-CodePudding

I am trying to navigate from welcomepage to screen tab but unable to do so because of the above error.

Part of welcome screen.dart

class WelcomePage extends StatelessWidget {
  static const routeName = '/welcome-screen';
  const WelcomePage({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.black,
        child: Stack(
          children: [
            Positioned.fill(
              child: Opacity(
                opacity: 0.3,
                child: Image.asset('assets/images/of_main_bg.png', fit: BoxFit.cover),
                ),
                ),
                
                  ThemeButton(
                    label: "Get Started!",
                    labelColor: AppColors.MAIN_COLOR,
                    color: Colors.transparent,
                    highlight: AppColors.MAIN_COLOR.withOpacity(0.5),
                    borderColor: AppColors.MAIN_COLOR,
                    borderWidth: 4,
                    onPressed: ()  {Navigator.push(
            context,
            MaterialPageRoute(
              builder: (context) {
                return TabsScreen(**ERROR**#What should I write here);
              },
            ),

Routes in main.dart

initialRoute: '/', // default is '/'
  routes: {
    '/': (ctx) => WelcomePage(),
    CategoryMealsScreen.routeName: (ctx) => CategoryMealsScreen(_availableMeals),
    MealDetailScreen.routeName: (ctx) => MealDetailScreen(_toggleFavorite, _isMealFavorite),
    FiltersScreen.routeName: (ctx) => FiltersScreen(_filters, _setFilters),
    TabsScreen.routeName: (ctx) => TabsScreen(_favoriteMeals),
    WelcomePage.routeName: (ctx) => WelcomePage(),
  },

class code in tabscreen.dart

 class TabsScreen extends StatefulWidget {
  static const routeName = '/tabs-screen';
  final List<Meal> favoriteMeals;

  TabsScreen(this.favoriteMeals);

How should i navigate from welcomepage to tabs_screen page?In order to navigate for the same what should I write in that ERROR place in welcome_screen.dart. If there's another method for navigation please do tell.

CodePudding user response：

Don't use named routes.

From https://docs.flutter.dev/cookbook/navigation/named-routes

Note: Named routes are no longer recommended for most applications. For more information, see Limitations in the navigation overview page.

CodePudding user response：

Your TabsScreen constructor is taking positional argument. You can pass empty list([]) there. But making name constructor with nullable data seems better to me.

class TabsScreen extends StatefulWidget {
  static const routeName = '/tabs-screen';
  final List<Meal>? favoriteMeals;

  TabsScreen({ this.favoriteMeals});

Now it is optional, and you can pass list like TabsScreen(favoriteMeals: yourData) and skip when you don't want to pass TabsScreen().

More about using-constructors