GoRouter package in Flutter - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the GoRouter package in Flutter?

GoRouter is a Flutter package that simplifies navigation and routing in Flutter apps by providing a declarative and easy-to-use API.

beginner

How do you define a route using GoRouter?

You define a route by creating a GoRoute object with a path and a builder function that returns the widget for that route.

beginner

What method do you use to navigate to a new route with GoRouter?

Use context.go('/path') to navigate to a new route by its path.

intermediate

How does GoRouter handle deep linking?

GoRouter supports deep linking by matching incoming URLs to defined routes, allowing the app to open specific screens directly.

intermediate

What is the purpose of the 'redirect' property in GoRouter?

The 'redirect' property lets you define logic to change navigation paths dynamically, such as redirecting unauthenticated users to a login page.

Which method is used to navigate to a new route in GoRouter?

A Navigator.push(context, route)

B context.go('/newRoute')

C setState(() => currentRoute = '/newRoute')

D Router.navigate('/newRoute')

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

How do you define a route in GoRouter?

A Using Navigator.pushNamed only

B Using MaterialPageRoute only

C By overriding build() method

D Using GoRoute with a path and builder

Routes in GoRouter are defined using GoRoute objects specifying path and widget builder.

What feature of GoRouter helps handle URLs from outside the app (deep links)?

A Route matching

B Stateful widgets

C setState

D InheritedWidget

GoRouter matches incoming URLs to routes, enabling deep linking.

Which GoRouter property allows redirecting users based on conditions?

A builder

B routes

C redirect

D initialLocation

The 'redirect' property lets you define conditional navigation logic.

What type of widget does the GoRoute builder return?

A A widget representing the screen for that route

B A Navigator widget

C A MaterialApp widget

D A StatelessWidget only

The builder returns the widget that displays the screen for the route.

Explain how to set up basic navigation using GoRouter in a Flutter app.

Think about defining routes and how to move between them.

Describe how GoRouter supports deep linking and why it is useful.

Consider how users can open the app from links.

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