Flutter Multiple Choice Questions (MCQs) and Answers

Q121 What is the role of the expect function in Flutter tests?

Q122 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

Q123 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

Q124 What could be a reason for a widget test failing unexpectedly?

Q125 How can you debug a failing Flutter test that involves asynchronous operations?

Q126 What approach can you take to isolate and identify the cause of a test failure in Flutter?

Q127 Which Flutter tool is used for debugging applications?

Q128 What does the flutter analyze command do?

Q129 How does the FlutterError class help in error handling?

Q130 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

Q131 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

Q132 What is a common reason for a widget not updating in Flutter?

Q133 How can you debug a performance issue in Flutter applications?

Q134 What should you do if you encounter a StateError in your Flutter app?

Q135 What is the purpose of using the RepaintBoundary widget in Flutter?

Q136 How does the const keyword help in optimizing Flutter performance?

Q137 What is the impact of using setState too frequently in Flutter?

Q138 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

Q139 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

Q140 What tool can you use to profile performance in a Flutter application?

Q141 How can you identify widgets that are rebuilding unnecessarily in Flutter?

Q142 What could be a reason for jank (stuttering) in a Flutter app animation?

Q143 What is the first step in preparing a Flutter app for release on the Google Play Store?

Q144 What file must be configured to set the app's version number and build number in Flutter?

Q145 Which tool is used to create a release build for iOS in Flutter?

Q146 How do you create a signed APK for Android in Flutter?
\n\n\nflutter build apk --release --split-per-abi\n

Q147 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

Q148 What could be a reason for a Flutter app crash only in release mode?

Q149 How can you debug a Flutter app that works in debug mode but fails in release mode?

Q150 Which technique can help minimize the size of a Flutter app for deployment?