Mobile App Development Interview Questions in Ahmedabad

function useFetch(url) { const [state, setState] = useState({ data: null, loading: true, error: null }); useEffect(() => { const controller = new AbortController(); fetch(url, { signal: controller.signal }) .then((r) => { if (!r.ok) throw new Error('HTTP ' + r.status); return r.json(); }) .then((data) => setState({ data, loading: false, error: null })) .catch((e) => { if (e.name !== 'AbortError') setState({ data: null, loading: false, error: e.message }); }); return () => controller.abort(); }, [url]); return state; }

flutter build appbundle --release --obfuscate --split-debug-info=build/symbols # Output: build/app/outputs/bundle/release/app-release.aab flutter build ipa --release --obfuscate --split-debug-info=build/symbols # Output: build/ios/ipa/*.ipa, upload with Transporter or xcrun altool # Version comes from pubspec.yaml, for example: # version: 2.3.1+45 (name 2.3.1, build number 45)

sealed class Result<T> {} class Success<T> extends Result<T> { Success(this.data); final T data; } class Failure<T> extends Result<T> { Failure(this.message); final String message; } Widget view(Result<List<String>> r) => switch (r) { Success(:final data) => ListView(children: [for (final s in data) Text(s)]), Failure(:final message) => Center(child: Text(message)), };

final productsProvider = FutureProvider.autoDispose<List<Product>>((ref) { final repo = ref.watch(productRepositoryProvider); return repo.fetchProducts(); }); class ProductsView extends ConsumerWidget { const ProductsView({super.key}); @override Widget build(BuildContext context, WidgetRef ref) { final products = ref.watch(productsProvider); return products.when( loading: () => const Center(child: CircularProgressIndicator()), error: (e, _) => const Center(child: Text('Failed to load')), data: (items) => ListView(children: [for (final p in items) ListTile(title: Text(p.name))]), ); } }

const cartSlice = createSlice({ name: 'cart', initialState: { items: [] }, reducers: { addItem(state, action) { const existing = state.items.find((i) => i.id === action.payload.id); if (existing) existing.qty += 1; else state.items.push({ ...action.payload, qty: 1 }); }, removeItem(state, action) { state.items = state.items.filter((i) => i.id !== action.payload); }, }, }); export const { addItem, removeItem } = cartSlice.actions; export const selectTotal = (s) => s.cart.items.reduce((t, i) => t + i.price * i.qty, 0);

sealed class ProductState {} class ProductLoading extends ProductState {} class ProductLoaded extends ProductState { ProductLoaded(this.items); final List<Product> items; } class ProductError extends ProductState { ProductError(this.message); final String message; } class ProductCubit extends Cubit<ProductState> { ProductCubit(this._repo) : super(ProductLoading()); final ProductRepository _repo; Future<void> load() async { emit(ProductLoading()); try { emit(ProductLoaded(await _repo.fetchProducts())); } catch (_) { emit(ProductError('Could not load products')); } } }

import * as Location from 'expo-location'; export function MyLocation() { const [coords, setCoords] = useState(null); const [error, setError] = useState(null); useEffect(() => { (async () => { const { status } = await Location.requestForegroundPermissionsAsync(); if (status !== 'granted') { setError('Location permission denied'); return; } const pos = await Location.getCurrentPositionAsync({}); setCoords(pos.coords); })(); }, []); if (error) return <Text>{error}</Text>; if (!coords) return <ActivityIndicator />; return <Text>{coords.latitude}, {coords.longitude}</Text>; }

final dio = Dio(BaseOptions( baseUrl: 'https://api.example.com', connectTimeout: const Duration(seconds: 10), receiveTimeout: const Duration(seconds: 15), )); dio.interceptors.add(InterceptorsWrapper( onRequest: (options, handler) async { final token = await secureStorage.read(key: 'access_token'); if (token != null) options.headers['Authorization'] = 'Bearer $token'; handler.next(options); }, onError: (e, handler) { if (e.response?.statusCode == 401) authNotifier.logout(); handler.next(e); }, ));

final router = GoRouter( initialLocation: '/', refreshListenable: authNotifier, redirect: (context, state) { final loggedIn = authNotifier.isLoggedIn; final goingToLogin = state.matchedLocation == '/login'; if (!loggedIn && !goingToLogin) return '/login'; if (loggedIn && goingToLogin) return '/'; return null; }, routes: [ GoRoute(path: '/', builder: (_, __) => const HomePage()), GoRoute(path: '/login', builder: (_, __) => const LoginPage()), GoRoute( path: '/product/:id', builder: (_, state) => ProductPage(id: state.pathParameters['id']!), ), ], );