Named routes in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a named route for the home screen.

Flutter

MaterialApp(
  initialRoute: '/',
  routes: {
    '/': (context) => [1](),
  },
)

Drag options to blanks, or click blank then click option'

AMyApp

BHomeScreen

CScaffold

DContainer

Attempts:

3 left

💡 Hint

Common Mistakes

Using a widget that is not the home screen.

Leaving the route value empty.

The named route '/' should point to the HomeScreen widget to show the home page.

2fill in blank

medium

Complete the code to navigate to the named route '/settings' when a button is pressed.

Flutter

ElevatedButton(
  onPressed: () {
    Navigator.of(context).[1]('/settings');
  },
  child: Text('Go to Settings'),
)

Drag options to blanks, or click blank then click option'

ApopAndPushNamed

Bpop

Cpush

DpushNamed

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop which goes back instead of forward.

Using push which requires a Route object, not a string.

To navigate to a named route, use Navigator.of(context).pushNamed with the route name.

3fill in blank

hard

Fix the error in the route definition to correctly map '/profile' to ProfileScreen widget.

Flutter

routes: {
  '/profile': ([1]) => ProfileScreen(),
}

Drag options to blanks, or click blank then click option'

ABuildContext

Bctx

Ccontext

Dcontext, state

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiple parameters in the route builder function.

Using a type name instead of a parameter name.

The route builder function takes a single parameter named context by convention.

4fill in blank

hard

Fill both blanks to define a named route '/details' that passes an argument to DetailsScreen.

Flutter

routes: {
  '/details': ([1]) => DetailsScreen(data: ModalRoute.of([2]!)!.settings.arguments),
}

Drag options to blanks, or click blank then click option'

Acontext

Bctx

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names for context and accessing arguments.

Trying to access arguments without context.

The context parameter is used to access the route settings and its arguments.

5fill in blank

hard

Fill all three blanks to navigate to '/edit' route and pass an argument 'itemId'.

Flutter

Navigator.of(context).[1](
  [2]: '/edit',
  [3]: 'itemId',
);

Drag options to blanks, or click blank then click option'

ApushNamed

BrouteName

Carguments

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop instead of pushNamed.

Passing arguments with wrong parameter names.

pushNamed navigates to a named route; routeName is the route string; arguments passes data.

Practice

1. What is the main purpose of using named routes in a Flutter app?

easy

A. To handle user input events

B. To style the app's theme

C. To manage app state globally

D. To give each screen a simple name for easy navigation

Solution

1. Step 1: Understand named routes concept

   Named routes assign simple string names to screens for easier navigation instead of using widget instances directly.

2. Step 2: Identify the main purpose

   This helps developers navigate between screens by referring to route names, making code cleaner and navigation simpler.

3. Final Answer:

   To give each screen a simple name for easy navigation -> Option D

4. Quick Check:

   Named routes = simple screen names for navigation [OK]

Hint: Named routes are simple screen names for navigation [OK]

Common Mistakes:

• Confusing named routes with app theming
• Thinking named routes manage app state
• Mixing named routes with event handling

2. Which of the following is the correct way to define named routes in a Flutter MaterialApp?

easy

A. MaterialApp(routeNames: {'/home': HomeScreen()})

B. MaterialApp(routes: {'/home': (context) => HomeScreen()})

C. MaterialApp(navigation: {'/home': HomeScreen()})

D. MaterialApp(namedRoutes: {'/home': () => HomeScreen()})

Solution

1. Step 1: Recall MaterialApp named routes syntax

   Named routes are defined using the 'routes' property with a map of route names to builder functions.

2. Step 2: Check each option

   MaterialApp(routes: {'/home': (context) => HomeScreen()}) correctly uses 'routes' with a map where the value is a function returning the widget. Other options use incorrect property names or values.

3. Final Answer:

   MaterialApp(routes: {'/home': (context) => HomeScreen()}) -> Option B

4. Quick Check:

   Use 'routes' with map of name to builder function [OK]

Hint: Use 'routes' property with map of names to builder functions [OK]

Common Mistakes:

• Using wrong property names like routeNames or navigation
• Assigning widget instance instead of builder function
• Missing context parameter in builder function

3. Given the following code snippet, what screen will be shown when Navigator.pushNamed(context, '/profile') is called?

MaterialApp(
  routes: {
    '/': (context) => HomeScreen(),
    '/profile': (context) => ProfileScreen(),
    '/settings': (context) => SettingsScreen(),
  },
)

medium

A. ProfileScreen

B. Error: Route not found

C. SettingsScreen

D. HomeScreen

Solution

1. Step 1: Check the routes map for '/profile'

   The routes map defines '/profile' as a key with ProfileScreen() as its widget builder.

2. Step 2: Understand Navigator.pushNamed behavior

   Calling Navigator.pushNamed with '/profile' will navigate to the ProfileScreen widget.

3. Final Answer:

   ProfileScreen -> Option A

4. Quick Check:

   Navigator.pushNamed('/profile') shows ProfileScreen [OK]

Hint: Match route name to widget in routes map [OK]

Common Mistakes:

• Confusing route names or mistyping them
• Assuming default screen shows instead of named route
• Expecting error when route exists

4. What is wrong with this code snippet for navigating to a named route?

Navigator.pushNamed('/settings');

medium

A. Navigator.pushNamed does not exist

B. Route name is incorrect

C. Missing BuildContext parameter

D. Should use Navigator.pop instead

Solution

1. Step 1: Check Navigator.pushNamed method signature

   Navigator.pushNamed requires a BuildContext as the first argument, then the route name as a string.

2. Step 2: Identify the error in the code

   The code calls Navigator.pushNamed with only the route name string, missing the required context parameter.

3. Final Answer:

   Missing BuildContext parameter -> Option C

4. Quick Check:

   Navigator.pushNamed needs context first [OK]

Hint: Navigator.pushNamed requires context and route name [OK]

Common Mistakes:

• Omitting the BuildContext argument
• Passing route name as first argument without context
• Confusing pushNamed with pop

5. You want to navigate from HomeScreen to DetailsScreen using named routes and pass an ID parameter. Which approach correctly passes the argument using Navigator.pushNamed?

hard

A. Navigator.pushNamed(context, '/details', arguments: 42);

B. Navigator.pushNamed(context, '/details/42');

C. Navigator.pushNamed('/details', arguments: 42);

D. Navigator.pushNamed(context, '/details', params: 42);

Solution

1. Step 1: Recall how to pass arguments with named routes

   Navigator.pushNamed accepts an optional 'arguments' parameter to pass data to the new screen.

2. Step 2: Analyze each option

   Navigator.pushNamed(context, '/details', arguments: 42); correctly passes context, route name, and arguments. Navigator.pushNamed(context, '/details/42'); tries to encode ID in route string (not standard). Navigator.pushNamed('/details', arguments: 42); misses context. Navigator.pushNamed(context, '/details', params: 42); uses wrong parameter name 'params'.

3. Final Answer:

   Navigator.pushNamed(context, '/details', arguments: 42); -> Option A

4. Quick Check:

   Use 'arguments' parameter to pass data [OK]

Hint: Pass data with 'arguments' parameter in pushNamed [OK]

Common Mistakes:

• Omitting context parameter
• Passing data in route string instead of arguments
• Using wrong parameter name like 'params'