Flutter MCQs
Q.1 If a Dart program throws a NoSuchMethodError, what is a likely cause?
A. A method is missing a return type
B. A method is called on a null object
C. A method is missing parameters
D. A method is using the wrong return type
Q.2 What is the correct way to handle a potential null value using null-aware operators in Dart?
\n\n\nint? a = null;
\nint b = a ?? 0;
\nprint(b);\n
A. 0
B. null
C. Throws an error
D. undefined
Q.3 How do you declare a nullable variable of type int in Dart?
A. int? num;
B. int num?;
C. nullable int num;
D. int num = null;
Q.4 What is the output of the following Dart code snippet?
\n\n\nvoid main() {
\n List numbers = [1, 2, 3];
\n print(numbers[1]);
\n}\n
A. 0
B. 1
C. 2
D. 3
Q.5 Which Dart collection is used to store key-value pairs?
A. List
B. Set
C. Map
D. Queue
Q.6 What does the async keyword indicate in Dart?
A. A function is synchronous
B. A function returns an integer
C. A function is asynchronous
D. A function returns a string
Q.7 Which of the following is NOT a built-in type in Dart?
A. int
B. float
C. String
D. bool
Q.8 What type does the main function return in a Dart application?
A. void
B. int
C. String
D. dynamic
Q.9 Which keyword is used to define a constant value in Dart?
A. constant
B. static
C. final
D. const
Q.10 What is Dart primarily used for in Flutter?
A. Back-end development
B. Database management
C. User interface development
D. None of the above
Q.11 Which of the following is a valid variable declaration in Dart?
A. var name = “John”;
B. int number = 42;
C. String text = ‘Hello’;
D. All of the above
Q.12 If running flutter doctor shows issues, what is a likely first step to resolve them?
A. Reinstall Flutter
B. Run flutter clean
C. Restart the IDE
D. Follow the recommendations provided by flutter doctor
Q.13 What might cause a Flutter project to fail to build after setup?
A. Incorrect project name
B. Missing dependencies
C. Using a dark theme
D. Incorrect Flutter version
Q.14 What command initializes a Flutter app in an existing directory?
A. flutter create –init
B. flutter start –init
C. flutter init
D. flutter create .
Q.15 Which file must be configured to use Firebase in a Flutter project?
A. index.html
B. main.dart
C. pubspec.yaml
D. settings.gradle
Q.16 What is the correct command to create a new Flutter project named my_app?
A. flutter new my_app
B. flutter init my_app
C. flutter create my_app
D. flutter start my_app
Q.17 What is the first step in setting up Flutter on a new machine?
A. Installing the Flutter SDK
B. Creating a new project
C. Running flutter doctor
D. Configuring the IDE
Q.18 How do you update the Flutter SDK?
A. flutter upgrade
B. flutter update
C. flutter refresh
D. flutter reinstall
Q.19 What is the purpose of the Flutter Doctor command?
A. To build the app
B. To run unit tests
C. To check the environment setup
D. To deploy the app
Q.20 Which operating system does not support Flutter development?
A. Windows
B. macOS
C. Linux
D. MS-DOS
Q.21 What command installs Flutter on macOS?
A. flutter install
B. brew install flutter
C. apt-get install flutter
D. install flutter
Q.22 Which IDE is commonly used for Flutter development?
A. Visual Studio
B. PyCharm
C. Eclipse
D. Android Studio
Q.23 Which widget in Flutter is used to create a visual hierarchy of the UI that controls the user interface layout?
A. MaterialApp
B. Widget
C. Scaffold
D. Column
Q.24 Which command is used to create a new Flutter project?
A. flutter run
B. flutter create
C. flutter build
D. flutter start
Q.25 What is a common use of Flutter’s hot reload feature?
A. To optimize app performance
B. To reduce the app size
C. To quickly view changes in the UI without restarting the app
D. To secure the app from vulnerabilities
Q.26 How does Flutter achieve high performance in rendering?
A. Using WebView
B. Using a JavaScript engine
C. Using Skia for rendering
D. Using native device widgets
Q.27 Which of the following platforms is NOT supported by Flutter?
A. iOS
B. Android
C. Web
D. Nintendo Switch
Q.28 What language is used to write Flutter apps?
A. Java
B. Kotlin
C. Swift
D. Dart
Q.29 Who maintains Flutter?
A. Microsoft
B. Facebook
C. Google
D. Apple
Q.30 What is the primary advantage of using Flutter in mobile app development?
A. To enable server-side rendering of applications
B. To provide a back-end framework for mobile apps
C. To facilitate the rapid development of cross-platform mobile applications with a single codebase
D. To enhance the security features of mobile applications
Q.31 What is the primary benefit of using the Bloc pattern for state management?
A. Simplifies UI design
B. Enhances app performance
C. Enforces a unidirectional data flow
D. Reduces code complexity
Q.32 In the context of state management, what does the term “lifting state up” refer to?
A. Moving state to a higher widget in the tree
B. Removing state from the widget tree
C. Copying state to a lower widget
D. Isolating state within a widget
Q.33 Which state management approach is built on top of InheritedWidget?
A. Redux
B. Provider
C. Bloc
D. Riverpod
Q.34 What method is used to update the state of a StatefulWidget?
A. setState
B. updateState
C. refreshState
D. changeState
Q.35 Which widget in Flutter is used to manage state locally?
A. StatefulWidget
B. StatelessWidget
C. InheritedWidget
D. Provider
Q.36 A Row widget’s children are not visible as expected. What could be a solution to this issue?
A. Increase the height of the parent widget
B. Use Expanded widgets
C. Check for overflow issues
D. Ensure children have a fixed width
Q.37 If a widget is overflowing in a Column, what could be a possible solution?
A. Remove the widget
B. Wrap the widget in an Expanded widget
C. Use a Row instead of Column
D. Change the widget’s color
Q.38 What is the purpose of the Align widget in Flutter?
\n\n\nAlign(
\n alignment: Alignment.topRight,
\n child: Text(“Hello”),
\n)\n
A. Centers the child widget
B. Aligns the child widget within its parent
C. Adds padding to the child widget
D. Adds a border to the child widget
Q.39 What does the Expanded widget do in the following code?
\n\n\nRow(
\n children: [
\n Expanded(child: Text(“Hello”)), \n Text(“World”),\n ],\n)\n
A. It collapses the child widget
B. It makes the child widget invisible
C. It expands the child to fill the available space
D. It aligns the child widget to the left
Q.40 What is the result of the following Flutter code?
\n\n\nRow(
\n children: [
\n Text(“Hello”),
\n Text(“World”),
\n ],
\n)\n
A. Displays “Hello” and “World” in a column
B. Displays “Hello” and “World” in a row
C. Displays “Hello” and “World” with padding
D. Throws an error
Q.41 What is the role of the Wrap widget in Flutter?
A. To arrange widgets in a horizontal row
B. To arrange widgets in a vertical column
C. To arrange widgets in a horizontal or vertical layout with wrapping
D. To arrange widgets in a stack
Q.42 How do you create a flexible layout in Flutter?
A. Using Column widget
B. Using Row widget
C. Using Flexible widget
D. Using Stack widget
Q.43 Which widget allows for both horizontal and vertical scrolling?
A. SingleChildScrollView
B. CustomScrollView
C. Scrollable
D. ScrollView
Q.44 What does the Padding widget do in Flutter?
A. Adds margin
B. Adds padding
C. Sets background color
D. Sets border
Q.45 Which widget is used to create a grid-based layout in Flutter?
A. ListView
B. Column
C. GridView
D. Stack
Q.46 Which layout widget allows you to arrange its children in a vertical column?
A. Row
B. Column
C. Stack
D. GridView
Q.47 A developer is using a Row widget, but its children are not evenly spaced. What could be the solution?
A. Use MainAxisAlignment.spaceBetween
B. Wrap children in Container widgets
C. Use Column instead of Row
D. Increase the width of the parent widget
Q.48 If a Text widget is not displaying correctly inside a Column, what could be a possible reason?
A. Incorrect text alignment
B. The Column widget does not support Text widgets
C. Text widget needs to be wrapped in an Expanded widget
D. Lack of padding
Q.49 What does the InkWell widget do in Flutter?
\n\n\nInkWell(
\n onTap: () {
\n print(“Tapped”);
\n },
\n child: Container(
\n padding: EdgeInsets.all(16.0),\n child: Text(“Tap Me”),\n ),\n)\n
A. Adds padding around the text
B. Displays a clickable area
C. Makes the text bold
D. Changes the background color
Q.50 What is the result of the following Flutter code?
\n\n\nColumn(
\n children: [
\n Text(“Hello”),
\n Text(“World”),
\n ],
\n)\n
A. Displays “Hello” and “World” in a row
B. Displays “Hello” and “World” in a column
C. Displays “Hello” and “World” with padding
D. Throws an error
Q.51 How would you create a circular avatar in Flutter?
\n\n\nCircleAvatar(
\n radius: 50,
\n backgroundImage: NetworkImage(‘https://example.com/avatar.jpg’),\n)\n
A. Using CircleAvatar widget
B. Using Container widget
C. Using ClipOval widget
D. Using Stack widget
Q.52 What does the following code snippet do?
\n\n\nContainer(
\n padding: EdgeInsets.all(16.0),
\n child: Text(“Hello World”),
\n)\n
A. Adds a margin around the text
B. Adds padding around the text
C. Centers the text
D. Makes the text bold
Q.53 Which widget can be used to overlay widgets on top of each other?
A. Column
B. Stack
C. Row
D. ListView
Q.54 Which widget would you use to create a fixed-size box in Flutter?
A. Container
B. SizedBox
C. Flexible
D. Wrap
Q,55 What does the Expanded widget do in a Row or Column?
A. It collapses the child widget
B. It makes the child widget invisible
C. It fills the available space in the parent
D. It aligns the child widget to the left
Q.56 Which widget is used for creating a scrollable list of items in a single column in Flutter?
A. GridView
B. ListView
C. Stack
D. Row
Q.57 What is the purpose of the Container widget in Flutter?
A. To organize the app’s routes
B. To define a single child widget with padding, margin, and constraints
C. To create a scrollable list
D. To handle user input
Q.58 Which widget in Flutter is used to display a long list of items?
A. GridView
B. ListView
C. Column
D. Row
Q.59 A Dart developer is experiencing unexpected behavior in their code. Which tool can they use to debug the issue?
A. dartfmt
B. dart analyze
C. dart doc
D. dart test
Q.60 How can you handle exceptions in Dart?
A. Using try and catch blocks
B. Using if-else statements
C. Using switch-case statements
D. Using break statements
Q.61 Which package is commonly used for making HTTP requests in Flutter?
A. http
B. requests
C. axios
D. fetch
Q.62 How can you debug an issue where the form is not validating as expected?
A. Ignore the issue
B. Check the form key and validators
C. Rebuild the form
D. Remove the validators
Q.63 What could be a reason for a TextField not updating its value correctly?
A. Incorrect onChanged callback
B. Missing controller
C. Not using a form key
D. Missing validation logic
Q.64 What does the following code snippet demonstrate?
\n\n\nFormField(
\n builder: (FormFieldState state) {
\n return Column(
\n children: [
\n TextField(
\n onChanged: (text) {
\n state.didChange(text);
\n },\n ),
\n Text(
\n state.errorText ?? ”,
\n style: TextStyle(color: Colors.red),
\n ),
\n ],
\n );
\n },
\n)\n
A. Basic form handling
B. Advanced form handling
C. Custom form field with validation
D. Form with multiple fields
Q.65 How would you create a form with multiple fields and a submit button in Flutter?
\n\n\nForm(
\n key: _formKey,
\n child: Column(
\n children: [\n TextFormField(),\n TextFormField(),\n ElevatedButton(\n onPressed: () {\n if (_formKey.currentState.validate()) {\n // Process data.
\n }
\n },
\n child: Text(‘Submit’),
\n ),\n
],\n ),
\n)\n
A. Using FormField widget
B. Using Column widget
C. Using ListView widget
D. Using Row widget
Q.66 How do you capture user input from a TextField in Flutter?
\n\n\nTextField(
\n onChanged: (text) {
\n // Capture input here\n },
\n)\n
A. Using the onSubmitted callback
B. Using the onChanged callback
C. Using a Validator
D. Using a GlobalKey
Q.67 What is the output of the following code?
\n\n\nTextField(
\n controller: TextEditingController(text: ‘Hello’),
\n)\n
A. Displays an empty field
B. Displays ‘Hello’ in the text field
C. Throws an error
D. Displays a password input
Q.68 How can you reset the state of a form in Flutter?
A. By setting the form fields to null
B. Using the reset method on the form key
C. Rebuilding the form widget
D. Using the clear method on the form key
Q.69 What is the purpose of a GlobalKey in a form?
A. To uniquely identify a form and access its state
B. To style the form
C. To handle user input
D. To create a new form
Q.70 How do you validate a form in Flutter?
A. Using a Validator object
B. Using the validate method on the form key
C. Using the checkValidity method
D. Using the validate attribute
Q.71 Which widget is commonly used to handle form input in Flutter?
A. TextField
B. Form
C. InputForm
D. FormField
Q.72 What could cause a “Route not found” error even if the route is defined in the MaterialApp?
A. Incorrect route name
B. Incorrect widget used
C. Navigator not initialized
D. Context is null
Q.73 How can you debug a routing issue where a screen is not found in Flutter?
A. Check for missing Navigator
B. Check for missing routes in MaterialApp
C. Check for missing Scaffold
D. Check for missing context
Q.74 What could be a reason for a navigation error stating “No MaterialLocalizations found”?
A. Missing Navigator widget
B. Missing MaterialApp widget
C. Incorrect route name
D. Missing Scaffold widget
Q.75 What does the following code do?
\n\n\nNavigator.pushAndRemoveUntil(
\n context,
\n MaterialPageRoute(builder: (context) => HomeScreen()),\n (Route route) => false,\n);\n
A. Adds a route to the stack
B. Removes all previous routes and navigates to HomeScreen
C. Replaces the current route
D. Navigates back to the initial route
Q.76 How would you navigate back to the previous screen in Flutter?
\n\n\nNavigator.of(context).???;\n
A. push
B. pop
C. replace
D. pushReplacement
Q.77 What is the result of the following code?
\n\n\nNavigator.push(
\n context,\n MaterialPageRoute(builder: (context) => NewScreen()),
\n);\n
A. Navigates to NewScreen
B. Replaces current screen with NewScreen
C. Removes the current screen
D. Closes the app
Q.78 Which navigation method would you use to replace the current route with a new route?
A. Navigator.push
B. Navigator.pop
C. Navigator.pushReplacement
D. Navigator.add
Q.79 What is the purpose of the onGenerateRoute property in the MaterialApp widget?
A. To handle route errors
B. To define a default route
C. To dynamically generate routes
D. To set the initial route
Q.80 How can you remove the current route in Flutter?
A. Navigator.pop
B. Navigator.push
C. Navigator.remove
D. Navigator.replace
Q.81 What does the Navigator.push method do in Flutter?
A. Removes the current route
B. Adds a new route to the stack
C. Replaces the current route
D. Closes the current route
Q.82 Which widget is used to define routes in a Flutter application?
A. Navigator
B. Routes
C. MaterialApp
D. Scaffold
Q.83 Why might a ChangeNotifier not notify its listeners even when notifyListeners is called?
A. The ChangeNotifier is not initialized
B. Listeners are not registered properly
C. There is no state change
D. The app is in debug mode
Q.84 How would you debug a state management issue where the state is not updating as expected?
A. Rebuild the app
B. Use print statements to trace state changes
C. Ignore the issue
D. Remove the stateful widget
Q.85 What is a common issue when using setState that prevents the UI from updating?
A. Not calling setState inside the build method
B. Calling setState inside the build method
C. Not calling setState at all
D. Calling setState with no state change
Q.86 What does the following code snippet demonstrate?
\n\n\nclass Counter with ChangeNotifier {
\n int _count = 0;
\n int get count => _count;\n void increment() {
\n _count++;\n notifyListeners();
\n }
\n}\n
A. Basic state management
B. Advanced state management
C. State management using ChangeNotifier
D. State management using Bloc
Q.87 How would you implement a Provider for state management in Flutter?
A. Using a StatefulWidget
B. Using a StatelessWidget
C. Using an InheritedWidget
D. Using a ChangeNotifierProvider
Q.88 What is the output of the following code?
\n\n\nclass MyWidget extends StatefulWidget {
\n @override\n _MyWidgetState createState() => _MyWidgetState();\n}\n\nclass _MyWidgetState extends State {\n int counter = 0;\n @override\n Widget build(BuildContext context) {\n return Column(\n children: [\n Text(‘$counter’),\n ElevatedButton(\n onPressed: () {\n setState(() {\n counter++;\n });\n },\n child: Text(‘Increment’),\n ),\n ],\n );\n }\n}\n
A. 0
B. 1
C. Counter increments by 1 on button press
D. Counter decrements by 1 on button press
Q.89 Which of the following is a disadvantage of using setState for state management?
A. It is difficult to implement
B. It is not scalable for large applications
C. It doesn’t support state changes
D. It doesn’t work with StatelessWidgets
Q.90 How does the ChangeNotifier class in Flutter work for state management?
A. It re-renders the entire widget tree
B. It notifies listeners when a change occurs
C. It prevents state changes
D. It provides a local state
Q.91 How can you simulate a tap gesture in a Flutter widget test?
A. By using the pump method
B. By using the tap method
C. By using the tester.tap method
D. By using the simulateTap method
Q.92 What is the primary purpose of the pumpWidget method in widget testing?
A. To render a widget
B. To test widget properties
C. To simulate user interaction
D. To create mock data
Q.93 Which of the following is used to create a widget test in Flutter?
A. testWidgets
B. testWidget
C. widgetTest
D. unitTest
Q.94 What package is commonly used for writing tests in Flutter?
A. flutter_test
B. flutter_testing
C. test_flutter
D. flutter_dev
Q.95 How can you debug an animation that is not running smoothly in Flutter?
A. Check the animation curve
B. Check the device’s performance
C. Check for unnecessary rebuilds
D. All of the above
Q.96 What could be a reason for an animation not starting in Flutter?
A. Incorrect animation duration
B. Animation controller not initialized
C. Animation listener not added
D. Incorrect animation curve
Q.97 What does the AnimatedBuilder widget do in the following code?
\n\n\nAnimatedBuilder(
\n animation: animation,
\n builder: (context, child) {
\n return Transform.scale(
\n scale: animation.value,
\n child: child,
\n );
\n },
\n child: FlutterLogo(),
\n);\n
A. It creates a scaling animation
B. It creates a fading animation
C. It creates a rotating animation
D. It creates a color-changing animation
Q.98 What is the purpose of the following code snippet?
\n\n\nAnimationController controller = AnimationController(
duration: const Duration(seconds: 2),
vsync: this
);
\nAnimation animation = Tween(
begin: 0.0,
end: 1.0
).
animate(controller);\n
A. It creates a delayed animation
B. It creates a repeating animation
C. It creates an animation with a duration of 2 seconds
D. It creates an animation with a delay of 2 seconds
Q.99 What does the CurvedAnimation class do in Flutter?
A. It handles the animation duration
B. It defines the start and end values
C. It applies a non-linear curve to an animation
D. It creates a linear animation
Q.100 What is the role of the TickerProvider in Flutter animations?
A. It provides a way to create animations
B. It provides a way to sync animations to the screen refresh rate
C. It provides a way to handle user input
D. It provides a way to control animation duration
Q.101 How does the Tween class work in Flutter animations?
A. It defines the start and end values of an animation
B. It controls the animation duration
C. It defines the animation curve
D. It handles user input
Q.102 Which widget in Flutter is used to animate the transition between two widgets?
A. AnimatedBuilder
B. AnimatedContainer
C. AnimatedSwitcher
D. AnimatedOpacity
Q.103 What class in Flutter is used to create basic animations?
A. AnimationController
B. Animation
C. Tween
D. AnimatedBuilder
Q.104 What could be a reason for a database operation failing in Flutter even if the query is correct?
A. Incorrect table name
B. Database not opened
C. Incorrect SQL syntax
D. Concurrency issues
Q.105 What could be a reason for a database operation failing in Flutter?
A. Incorrect table name
B. Valid query
C. Proper database connection
D. Correct SQL syntax
Q.106 How do you update a specific row in a table using sqflite?
\n\n\nawait db.update(
‘users’,
{‘name’: ‘John’},
where: ‘id = ?’,
whereArgs: [1]
);\n
A. Using db.modify method
B. Using db.update method
C. Using db.edit method
D. Using db.change method
Q.107 How would you query all rows from a table named ‘users’ in SQLite using sqflite?
\n\n\nDatabase db = await openDatabase(‘my_db.db’);
\nList result = await db.query(‘users’);\n
A. Using db.select method
B. Using db.fetch method
C. Using db.query method
D. Using db.get method
Q.108 What is the output of the following code?
\n\n\nDatabase db = await openDatabase(‘my_db.db’);
\nawait db.insert(‘my_table’, {‘name’: ‘John’, ‘age’: 30});\n
A. Inserts data into ‘my_table’
B. Deletes data from ‘my_table’
C. Updates data in ‘my_table’
D. Creates ‘my_table’
Q.109 Which of the following is a benefit of using an ORM (Object-Relational Mapping) like moor?
A. Direct SQL queries
B. Automatic schema updates
C. Manual data handling
D. Low-level database access
Q.110 How do you define a table schema in SQLite for Flutter?
A. Using SQL commands
B. Using Dart classes
C. Using JSON
D. Using XML
Q.111 What method is used to open a database connection in the sqflite package?
A. openDatabase
B. connectDatabase
C. initDatabase
D. startDatabase
Q.112 Which package is commonly used for SQLite database integration in Flutter?
A. sqflite
B. moor
C. firebase
D. realm
Q.113 How can you debug a network issue where the response is not as expected in Flutter?
A. Check the request URL
B. Check the response headers
C. Check the request and response payloads
D. All of the above
Q.114 What could be a reason for a network request failing in Flutter?
A. Incorrect URL
B. Valid URL
C. Strong internet connection
D. Valid API key
Q.115 How do you handle errors when making an HTTP request in Flutter?
\n\n\ntry {
\n var response = await http.get(url);
\n if (response.statusCode == 200) {
\n print(‘Success’);
\n } else {
\n print(‘Error: ${response.statusCode}’);
\n }
\n} catch (e) {
\n print(‘Exception: $e’);
\n}\n
A. Ignore errors
B. Check response status code and catch exceptions
C. Only check response body
D. Use a different package
Q.116 How would you handle an HTTP POST request in Flutter?
\n\n\nvar url = ‘https://api.example.com/data’;
\nvar response = await http.post(url, body: {‘key’: ‘value’});\n
A. Using the http.get method
B. Using the http.post method
C. Using the http.send method
D. Using the http.fetch method
Q.117 What is the output of the following code?
\n\n\nvar url = ‘https://api.example.com/data’;
\nvar response = await http.get(url);
\nprint(response.body);\n
A. Prints the response body
B. Prints the response headers
C. Prints the response status code
D. Throws an error
Q.118 How do you parse a JSON response in Flutter?
A. Using the jsonDecode function
B. Using the jsonEncode function
C. Using the JSON.parse function
D. Using the parse function
Q.119 What is the purpose of the async and await keywords in Dart?
A. To handle synchronous operations
B. To handle asynchronous operations
C. To define variables
D. To create classes
Q.120 What method is used to send a GET request in the http package?
A. http.send
B. http.get
C. http.post
D. http.fetch
Q.121 Which technique can help minimize the size of a Flutter app for deployment?
A. Enabling ProGuard
B. Using minification
C. Removing unused resources
D. Using compressed images
Q.122 How can you debug a Flutter app that works in debug mode but fails in release mode?
A. Check debug output
B. Check release logs
C. Check dependencies
D. Check widget tree
Q.123 What could be a reason for a Flutter app crash only in release mode?
A. Debug mode configurations
B. Missing release configurations
C. Incorrect widget tree
D. Using const keywords
Q.124 What is the purpose of the following code in the build.gradle file?
\n\n\nsigningConfigs {
\n release {
\n keyAlias ‘my-key-alias’
\n keyPassword ‘my-key-password’
\n storeFile file(‘my-key.jks’)
\n storePassword ‘my-store-password’
\n }
\n}\n
A. It configures ProGuard
B. It configures app signing
C. It configures versioning
D. It configures dependencies
Q.125 How do you create a signed APK for Android in Flutter?
\n\n\nflutter build apk –release –split-per-abi\n
A. Using flutter run command
B. Using flutter build apk command
C. Using flutter deploy command
D. Using flutter release command
Q.126 Which tool is used to create a release build for iOS in Flutter?
A. flutter run
B. flutter build ios
C. flutter deploy
D. flutter release
Q.127 What file must be configured to set the app’s version number and build number in Flutter?
A. pubspec.yaml
B. build.gradle
C. AndroidManifest.xml
D. MainActivity.java
Q.128 What is the first step in preparing a Flutter app for release on the Google Play Store?
A. Enable ProGuard
B. Configure app signing
C. Change app version
D. Optimize images
Q.129 What could be a reason for jank (stuttering) in a Flutter app animation?
A. Overdraw in the UI
B. Optimized layout
C. Efficient state management
D. Using stateless widgets
Q.130 How can you identify widgets that are rebuilding unnecessarily in Flutter?
A. Use the debugPrint function
B. Use the shouldRebuild method
C. Use the Debug flags
D. Use the Widget rebuild profiler
Q.131 What tool can you use to profile performance in a Flutter application?
A. Flutter Doctor
B. Flutter Analyzer
C. Flutter Profiler
D. Flutter Inspector
Q.132 How would you optimize a widget that builds complex layouts frequently?
\n\n\nclass MyWidget extends StatelessWidget {
\n @override
\n Widget build(BuildContext context) {
\n return ComplexLayoutWidget();
\n }
\n}\n
A. Use StatefulWidget
B. Use StatelessWidget
C. Use Memoization
D. Use RepaintBoundary
Q.133 How can you optimize a list with a large number of items in Flutter?
\n\n\nListView.builder(
\n itemCount: 1000,
\n itemBuilder: (context, index) {
\n return ListTile(
\n title: Text(‘Item $index’),
\n );\n
},
\n);\n
A. Use ListView
B. Use ListView.builder
C. Use ListView.custom
D. Use ListView.separated
Q.134 What is the impact of using setState too frequently in Flutter?
A. Improves performance
B. Reduces performance
C. Has no effect
D. Increases battery usage
Q.135 How does the const keyword help in optimizing Flutter performance?
A. It reduces widget size
B. It prevents widget rebuilds
C. It simplifies widget structure
D. It enhances animation performance
Q.136 What is the purpose of using the RepaintBoundary widget in Flutter?
A. To prevent widget rebuilds
B. To isolate parts of the widget tree for performance optimization
C. To handle user input
D. To improve layout performance
Q.137 What should you do if you encounter a StateError in your Flutter app?
A. Restart the app
B. Check the widget state lifecycle
C. Update the Flutter SDK
D. Rebuild the widget tree
Q.138 How can you debug a performance issue in Flutter applications?
A. Use Flutter Doctor
B. Use Flutter Analyzer
C. Use Flutter Profiler
D. Use Flutter Inspector
Q.139 What is a common reason for a widget not updating in Flutter?
A. Incorrect state management
B. Syntax error
C. Missing dependency
D. Outdated Flutter version
Q.140 How would you handle an asynchronous error in Flutter?
\n\n\nFuture fetchData() async {
\n try {\n var data = await fetchFromApi();
\n } catch (e) {
\n print(‘Error: $e’);
\n }
\n}\n
A. Using try-catch
B. Using Future.error
C. Using async-catch
D. Using then-catch
Q.141 What is the output of the following code if an exception is thrown?
\n\n\ntry {
\n throw Exception(‘Error’);
\n} catch (e) {
\n print(‘Caught: $e’);
\n}\n
A. Uncaught error
B. Exception: Error
C. Caught: Exception: Error
D. Error thrown
Q.142 How does the FlutterError class help in error handling?
A. It logs errors to a file
B. It displays errors in the console
C. It provides custom error messages
D. It helps in exception tracking
Q.143 What does the flutter analyze command do?
A. Compiles the code
B. Runs the application
C. Analyzes the code for issues
D. Deploys the application
Q.144 Which Flutter tool is used for debugging applications?
A. 145 Flutter Doctor
B. Flutter Analyzer
C. Flutter Debugger
D. Flutter Inspector
Q.145 What approach can you take to isolate and identify the cause of a test failure in Flutter?
A. Remove all expect statements
B. Test the app manually
C. Run the test in verbose mode
D. Break the test into smaller tests
Q.146 How can you debug a failing Flutter test that involves asynchronous operations?
A. Use print statements
B. Use debugPrint
C. Use expectAsync
D. Use await and async
Q.147 What could be a reason for a widget test failing unexpectedly?
A. Incorrect widget key
B. Missing dependencies
C. Incorrect test setup
D. All of the above
Q.148 How would you test a button tap that triggers a state change?
\n\n\ntestWidgets(‘Button tap increments counter’, (WidgetTester tester) async {
\n await tester.pumpWidget(MyApp());
\n await tester.tap(find.byType(ElevatedButton));
\n await tester.pump();
\n expect(find.text(‘1’), findsOneWidget);
\n});\n
A. It tests the button’s color
B. It tests the button’s visibility
C. It tests the state change after button tap
D. It tests the button’s size
Q.149 What does the following code test?
\n\n\ntestWidgets(‘MyWidget has a title and message’, (WidgetTester tester) async {
\n await tester.pumpWidget(MyWidget());
\n final titleFinder = find.text(‘Title’);
\n final messageFinder = find.text(‘Message’);
\n expect(titleFinder, findsOneWidget);
\n expect(messageFinder, findsOneWidget);
\n});\n
A. It tests the widget’s layout
B. It tests the widget’s interaction
C. It tests for the presence of text widgets
D. It tests for the widget’s state
Q.150 What is the role of the expect function in Flutter tests?
A. To compare actual and expected results
B. To render the widget
C. To initialize the test environment
D. To create mock data
