Navigator errors(assertion failed: D:\…\widgets\navigator.dart:4165 ! _debuglocked is not true ; the relevant error-causing widget was maindrawer

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Dart

Flutter

In this, I think I am getting errors at the navigators. If I comment both of them out the app runs fine(except the page change). The first navigator is giving this error when I comment it out .The second navigator is working but not as it is supposed to (it gets called when I click on the drawer Icon rather than when i click on the settings icon).

import 'package:flutter/material.dart';
import 'package:meals_app/Screens/Filters_screen.dart';

class MainDrawer extends StatelessWidget {
  const MainDrawer({Key? key}) : super(key: key);
  Widget buildListTile(String title, IconData icon, Function tapHandler) {
    return ListTile(
      leading: Icon(
        icon,
        size: 26,
      ),
      title: Text(
        title,
        style: TextStyle(
            fontFamily: 'RobotoCondensed',
            fontSize: 24,
            fontWeight: FontWeight.bold),
      ),
      onTap: tapHandler(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Drawer(
      child: Column(children: <Widget>[
        Container(
          height: 120,
          width: double.infinity,
          padding: EdgeInsets.all(20),
          alignment: Alignment.centerLeft,
          color: Colors.white,
          child: Text(
            'data coming',
            style: TextStyle(
                fontWeight: FontWeight.w900, fontSize: 30, color: Colors.black),
          ),
        ),
        SizedBox(
          height: 20,
        ),
        buildListTile('Meals', Icons.restaurant, () {
          Navigator.of(context).pushNamed('/');
        }),
        buildListTile('Settings', Icons.settings, () {
          Navigator.of(context).pushNamed(Filterscreen.routeName);
        })
      ]),
    );
  }
}

This is the drawerscreen ^^

Main.dart-

import 'package:flutter/material.dart';
import 'package:meals_app/Screens/Filters_screen.dart';
import 'package:meals_app/Screens/category_meals_screen.dart';
import 'package:meals_app/Screens/catogeries_screen.dart';
import 'package:meals_app/Screens/meal_detail_screen.dart';
import 'package:meals_app/Screens/tabs_screen.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'MealsApp',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        accentColor: Colors.greenAccent,
        canvasColor: const Color.fromRGBO(255, 253, 220, 1),
        fontFamily: 'Raleway',
        textTheme: ThemeData.light().textTheme.copyWith(
              bodyText1: const TextStyle(color: Colors.red),
              bodyText2: const TextStyle(
                  color: Colors.black12,
                  fontWeight: FontWeight.bold,
                  fontFamily: 'RobotoCondensed',
                  fontSize: 24),
            ),
      ),
      home: TabScreen(), 
      initialRoute: '/',
      routes: {
        // '/': (ctx) => TabScreen(), //This is our default route
        CategoryMealScreen.routeName: (ctx) => CategoryMealScreen(),
        MealDeatilScreen.routeName: (ctx) => MealDeatilScreen(),
        Filterscreen.routeName: (ctx) => Filterscreen(),
      },
     
      onUnknownRoute: (settings) {
        return MaterialPageRoute(builder: (ctx) => categorieScreen());
      }, 
    );
  }
}

What I have tried:

I tried wrapping it(1st navigator) in addPostFrameCallback but it did not work