GoRouter package in Flutter

Introduction

GoRouter helps you move between screens in your Flutter app easily. It makes navigation simple and organized.

When you want to switch between different pages in your app.

When you need to pass information from one screen to another.

When you want to handle deep links or URLs in your app.

When you want to keep your navigation code clean and easy to manage.

Syntax

Flutter

final GoRouter router = GoRouter(
  routes: [
    GoRoute(
      path: '/',
      builder: (context, state) => HomeScreen(),
    ),
    GoRoute(
      path: '/details',
      builder: (context, state) => DetailsScreen(),
    ),
  ],
);

GoRouter is created with a list of GoRoute objects.

Each GoRoute has a path and a builder that returns the screen widget.

Examples

This route shows the HomeScreen when the app starts.

Flutter

GoRoute(
  path: '/',
  builder: (context, state) => HomeScreen(),
)

This route passes a userId from the URL to the ProfileScreen.

Flutter

GoRoute(
  path: '/profile/:userId',
  builder: (context, state) {
    final userId = state.params['userId']!;
    return ProfileScreen(userId: userId);
  },
)

Sample App

This app starts on the Home screen with a button. When you tap the button, it navigates to the Details screen using GoRouter.

Flutter

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

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

class MyApp extends StatelessWidget {
  final GoRouter _router = GoRouter(
    routes: [
      GoRoute(
        path: '/',
        builder: (context, state) => HomeScreen(),
      ),
      GoRoute(
        path: '/details',
        builder: (context, state) => DetailsScreen(),
      ),
    ],
  );

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      routerConfig: _router,
      title: 'GoRouter Demo',
    );
  }
}

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Home')),
      body: Center(
        child: ElevatedButton(
          onPressed: () => context.go('/details'),
          child: Text('Go to Details'),
        ),
      ),
    );
  }
}

class DetailsScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Details')),
      body: Center(child: Text('Welcome to Details Screen!')),
    );
  }
}

Important Notes

Use context.go('/path') to navigate to a new screen.

Paths can include parameters like /profile/:id to pass data.

GoRouter works well with Flutter's MaterialApp.router for easy setup.

Summary

GoRouter makes screen navigation simple and clear.

Define routes with paths and screen builders.

Use context.go() to move between screens.

Practice

1. What is the main purpose of the GoRouter package in Flutter?

easy

A. To handle database connections

B. To manage state across widgets

C. To style widgets with custom themes

D. To simplify and manage screen navigation in Flutter apps

Solution

1. Step 1: Understand GoRouter's role

   GoRouter is designed to make navigation between screens easier and clearer in Flutter apps.

2. Step 2: Compare with other options

   Options A, C, and D relate to database, styling, and state management, which are not GoRouter's purpose.

3. Final Answer:

   To simplify and manage screen navigation in Flutter apps -> Option D

4. Quick Check:

   GoRouter = Navigation helper [OK]

Hint: Remember GoRouter is about moving between screens [OK]

Common Mistakes:

• Confusing navigation with state management
• Thinking GoRouter styles widgets
• Assuming GoRouter handles databases

2. Which of the following is the correct way to navigate to a new route named '/profile' using GoRouter?

easy

A. context.navigateTo('/profile');

B. Navigator.push('/profile');

C. context.go('/profile');

D. goRouter.push('/profile');

Solution

1. Step 1: Recall GoRouter navigation syntax

   GoRouter uses context.go(path) to navigate to a route.

2. Step 2: Check each option

   context.go('/profile'); uses context.go('/profile'), which is correct. Options B, C, and D use incorrect methods or objects.

3. Final Answer:

   context.go('/profile'); -> Option C

4. Quick Check:

   Use context.go() for navigation [OK]

Hint: Use context.go() with the route path to navigate [OK]

Common Mistakes:

• Using Navigator.push instead of context.go
• Calling non-existent methods like context.navigateTo
• Trying to call goRouter.push without context

3. Given this GoRouter setup:

final router = GoRouter(
  routes: [
    GoRoute(path: '/', builder: (context, state) => HomeScreen()),
    GoRoute(path: '/settings', builder: (context, state) => SettingsScreen()),
  ],
);

// In HomeScreen's button onPressed:
context.go('/settings');

What screen will be displayed after pressing the button?

medium

A. HomeScreen

B. SettingsScreen

C. An error screen

D. A blank screen

Solution

1. Step 1: Analyze the routes defined

   There are two routes: '/' for HomeScreen and '/settings' for SettingsScreen.

2. Step 2: Understand the navigation call

   The button calls context.go('/settings'), which navigates to the '/settings' route.

3. Final Answer:

   SettingsScreen -> Option B

4. Quick Check:

   context.go('/settings') shows SettingsScreen [OK]

Hint: context.go(path) shows the screen for that path [OK]

Common Mistakes:

• Assuming context.go('/') stays on HomeScreen
• Thinking navigation causes error without extra setup
• Confusing builder with route path

4. What is wrong with this GoRouter route definition?

GoRoute(
  path: '/profile',
  builder: (context) => ProfileScreen(),
)

medium

A. The builder function is missing the second parameter 'state'

B. The path should start with a capital letter

C. ProfileScreen() must be wrapped in a MaterialApp

D. GoRoute requires a name property

Solution

1. Step 1: Check GoRoute builder signature

   The builder function must accept two parameters: context and state.

2. Step 2: Identify the error

   The code only has one parameter (context), missing the required 'state' parameter.

3. Final Answer:

   The builder function is missing the second parameter 'state' -> Option A

4. Quick Check:

   builder(context, state) needs two parameters [OK]

Hint: Builder always needs (context, state) parameters [OK]

Common Mistakes:

• Omitting the 'state' parameter in builder
• Thinking path must be capitalized
• Assuming name property is mandatory
• Wrapping screen in MaterialApp inside builder

5. You want to pass a user ID as a parameter in the route path using GoRouter. Which route definition and navigation call are correct?

// Route definition options:
A) GoRoute(path: '/user/:id', builder: (context, state) => UserScreen(id: state.params['id']!))
B) GoRoute(path: '/user', builder: (context, state) => UserScreen(id: state.params['id']!))

// Navigation call options:
1) context.go('/user/123');
2) context.go('/user?id=123');

hard

A. Use route A with navigation call 1

B. Use route A with navigation call 2

C. Use route B with navigation call 1

D. Use route B with navigation call 2

Solution

1. Step 1: Understand route parameter syntax

   Route path with ':id' means the ID is part of the path, so '/user/:id' is correct for path parameters.

2. Step 2: Match navigation call to route

   To pass the ID in the path, navigation must be like '/user/123', so call 1 matches route A.

3. Final Answer:

   Use route A with navigation call 1 -> Option A

4. Quick Check:

   Path param ':id' needs '/user/123' navigation [OK]

Hint: Use ':param' in path and '/value' in go() call [OK]

Common Mistakes:

• Using query parameters with path param syntax
• Missing ':id' in route path
• Passing ID as query string when route expects path param