Assertion Failure in go_router package: 'package:go_router/src/parser.dart': Failed assertion: line 63 pos 12: 'routeInformation.state != null'

Question

The error is within the go_router package and is related to an assertion failure in the parser.dart file. The specific assertion that failed is at line 63, position 12, and it checks whether routeInformation.state is not null. The assertion is there to ensure that the state associated with a route is not null.

'package:go_router/src/parser.dart': Failed assertion: line 63 pos 12: 'routeInformation.state != null': is not true.

my AppRouts class

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:quizapp/screens/home/home.dart';
import '../../screens/error/error_page.dart';
import '../../screens/splash/splash_screen.dart';
import 'app_routers.dart';

class MyAppRouts {
  GoRouter route = GoRouter(
    routes: [
      GoRoute(
        name: MyAppRoutesConstent.splashScreenRoutename,
        path: '/',
        pageBuilder: (context, state) {
          return const MaterialPage(child: SplashScreen());
        },
      ),
      GoRoute(
        name: MyAppRoutesConstent.homeRoutename,
        path: '/home',
        pageBuilder: (context, state) {
          return const MaterialPage(child: HomePage());
        },
      ),
    ],
    errorPageBuilder: (context, state) {
      return const MaterialPage(child: ErrorPage());
    },
  );
}

Im new to GoRouter package what is the problem hear i need lord splash screen as my first screen and this is my main.dart file

import 'package:flutter/material.dart';

import 'project/routes/app_routers_const.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: 'Flutter Quiz App',
      debugShowCheckedModeBanner: false,
      routeInformationParser: MyAppRouts().route.routeInformationParser,
      routerDelegate: MyAppRouts().route.routerDelegate,
    );
  }
}

i need lord splash screen as my first screen

Answer 1

As per the documentation, configure the MaterialApp.router like this:

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      routerConfig: MyAppRouts().route,
    );
  }
}

and set an initial path for splash screen:

GoRouter route = GoRouter(initialLocation : "/splashScreen" , ..);

Answer 2

if you are still wondering what's wrong just make sure you do this,

AppRouts class

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:quizapp/screens/home/home.dart';
import '../../screens/error/error_page.dart';
import '../../screens/splash/splash_screen.dart';
import 'app_routers.dart';

class MyAppRouts {
  GoRouter route = GoRouter(
    initialLocation: "/", // Any location you want to show first
    routes: [
      GoRoute(
        name: MyAppRoutesConstent.splashScreenRoutename,
        path: '/',
        pageBuilder: (context, state) {
          return const MaterialPage(child: SplashScreen());
        },
      ),
      GoRoute(
        name: MyAppRoutesConstent.homeRoutename,
        path: '/home',
        pageBuilder: (context, state) {
          return const MaterialPage(child: HomePage());
        },
      ),
    ],
    errorPageBuilder: (context, state) {
      return const MaterialPage(child: ErrorPage());
    },
  );
}

main.dart

import 'package:flutter/material.dart';

import 'project/routes/app_routers_const.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: 'Flutter Quiz App',
      debugShowCheckedModeBanner: false,
      routerConfig: MyAppRouts().route,
      //make sure you must not add any other data like 
      //"routeInformationParser" and "routerDelegate" they'll cause error
    );
  }
}