Flutter code snippets

class WalletTx {
  const WalletTx(this.title, this.cents, this.at); // positive = mone…
  final String title;
  final int cents;
  final DateTime at;
}
String formatMoney(int cents, {String symbol = '\$'}) {
  final abs = cents.abs();
  final whole = (abs ~/ 100).toString().replaceAllMapped(RegExp(r'\B(…

abstract class TokenStore {
  Future<String?> readAccess();
  Future<String?> readRefresh();
  Future<void> save({required String access, required String refresh}…
  Future<void> clear();
}
/// Exchanges a refresh token for a new pair, or throws.
typedef Refresher = Future<({String access, String refresh})> Functio…
class SessionExpired implements Exception {}

@immutable
class AppColors extends ThemeExtension<AppColors> {
  const AppColors({required this.success, required this.warning, requ…
  final Color success, warning, priceTag;
  static const light = AppColors(
    success: Color(0xFF1B7F4B),
    warning: Color(0xFFB26A00),
    priceTag: Color(0xFFE8F1FF),
  );

/// Sweeps a highlight across every skeleton box placed under it.
class Shimmer extends StatefulWidget {
  const Shimmer({super.key, required this.child});
  final Widget child;
  @override
  State<Shimmer> createState() => _ShimmerState();
}
class _ShimmerState extends State<Shimmer> with SingleTickerProviderS…
  late final AnimationController _c =

class AppStrings {
  AppStrings(this.locale);
  final Locale locale;
  static const supported = [Locale('en'), Locale('ar')];
  static const _table = <String, Map<String, String>>{
    'en': {'book': 'Book now', 'greeting': 'Hello, {name}'},
    'ar': {'book': 'احجز الآن', 'greeting': 'مرحبا، {name}'},
  };
  static AppStrings of(BuildContext c) => Localizations.of<AppStrings…

class RatingResult {
  const RatingResult(this.stars, this.tags, this.comment);
  final int stars;
  final Set<String> tags;
  final String comment;
}
/// Returns null when the user dismisses the sheet.
Future<RatingResult?> showRatingSheet(BuildContext context,
    {List<String> tags = const ['On time', 'Polite', 'Great quality']…

enum PushState { granted, askable, blocked }
class PushPermission {
  /// Reads the current state without showing any system dialog.
  static Future<PushState> check() async {
    final s = await Permission.notification.status;
    if (s.isGranted || s.isProvisional) return PushState.granted;
    if (s.isPermanentlyDenied) return PushState.blocked;
    return PushState.askable;
  }

class SignatureController extends ChangeNotifier {
  final List<List<Offset>> strokes = [];
  bool get isEmpty => strokes.isEmpty;
  void start(Offset p) { strokes.add([p]); notifyListeners(); }
  void extend(Offset p) { strokes.last.add(p); notifyListeners(); }
  void clear() { strokes.clear(); notifyListeners(); }
  /// Renders the strokes to PNG bytes on a white background.
  Future<Uint8List> toPng(Size size) async {
    final rec = ui.PictureRecorder();

class Plan {
  const Plan({required this.id, required this.name, required this.mon…
  final String id;
  final String name;
  final int monthlyCents;
  final List<String> perks;
}
class PlanSelector extends StatefulWidget {
  const PlanSelector({super.key, required this.plans, required this.o…

abstract class PhoneAuthApi {
  Future<void> requestCode(String phone);
  Future<void> verifyCode(String phone, String code); // throws on a …
}
enum LoginStep { phone, code }
class PhoneLoginController extends ChangeNotifier {
  PhoneLoginController(this._api);
  final PhoneAuthApi _api;
  LoginStep step = LoginStep.phone;

class TrackEvent {
  const TrackEvent(this.title, {this.detail, this.at});
  final String title;
  final String? detail;
  final DateTime? at; // null means it has not happened yet
}
class TrackingTimeline extends StatelessWidget {
  const TrackingTimeline({super.key, required this.events});
  final List<TrackEvent> events; // in delivery order

typedef PageFetcher<T> = Future<List<T>> Function(int page);
class PagedList<T> extends StatefulWidget {
  const PagedList({super.key, required this.fetch, required this.item…
  final PageFetcher<T> fetch;
  final Widget Function(BuildContext, T) itemBuilder;
  final int pageSize;
  @override
  State<PagedList<T>> createState() => _PagedListState<T>();
}

class OtpInput extends StatefulWidget {
  const OtpInput({super.key, this.length = 6, required this.onComplet…
  final int length;
  final ValueChanged<String> onCompleted;
  @override
  State<OtpInput> createState() => _OtpInputState();
}
class _OtpInputState extends State<OtpInput> {
  final _controller = TextEditingController();

abstract class AvailabilityApi {
  Future<void> setOnline(bool online);
  Future<void> heartbeat();
}
class AvailabilityController extends ChangeNotifier {
  AvailabilityController(this._api, {this.interval = const Duration(s…
  final AvailabilityApi _api;
  final Duration interval;
  bool _online = false, _pending = false;

typedef Fetcher = Future<Object?> Function(); // returns decoded JSON
class Cached<T> {
  const Cached(this.value, {required this.fromCache, required this.sa…
  final T value;
  final bool fromCache; // true while showing stored data
  final DateTime savedAt;
}
class CachedRepository<T> {
  CachedRepository({

class ServiceTile {
  const ServiceTile({required this.label, required this.icon, require…
  final String label;
  final IconData icon;
  final String route;
  final String? badge; // e.g. "New" or "20% off"
  final bool enabled;
}
class ServiceGrid extends StatelessWidget {

class PhotoPickerController extends ChangeNotifier {
  PhotoPickerController({this.max = 6, this.maxEdge = 1600, this.qual…
  final int max, maxEdge, quality, maxBytes;
  final _picker = ImagePicker();
  final List<File> files = [];
  String? message;
  Future<void> fromGallery() async {
    final left = max - files.length;
    if (left <= 0) return _warn('You can add up to $max photos.');

class StateView extends StatelessWidget {
  const StateView({super.key, required this.icon, required this.title…
  final IconData icon;
  final String title;
  final String? message;
  final String? actionLabel;
  final VoidCallback? onAction;
  /// Nothing to show yet.
  factory StateView.empty({String title = 'Nothing here yet', String?…

typedef SearchFn<T> = Future<List<T>> Function(String query);
class DebouncedSearch<T> extends StatefulWidget {
  const DebouncedSearch({
    super.key,
    required this.search,
    required this.resultBuilder,
    this.delay = const Duration(milliseconds: 350),
    this.minLength = 2,
  });

typedef SlotLoader = Future<Set<TimeOfDay>> Function(DateTime day); /…
class SlotPicker extends StatefulWidget {
  const SlotPicker({super.key, required this.load, required this.onCh…
  final SlotLoader load;
  final ValueChanged<DateTime?> onChanged;
  final int days;
  @override
  State<SlotPicker> createState() => _SlotPickerState();
}

class Coupon {
  const Coupon(this.code, this.percentOff);
  final String code;
  final int percentOff;
}
typedef CouponValidator = Future<Coupon> Function(String code); // th…
enum _Phase { idle, checking, applied }
class CouponField extends StatefulWidget {
  const CouponField({super.key, required this.validate, required this…

class FlowStep {
  const FlowStep({required this.title, required this.formKey, require…
  final String title;
  final GlobalKey<FormState> formKey; // each step validates independ…
  final Widget body;
  final String Function()? summary; // shown when the step is collaps…
}
class StepFlow extends StatefulWidget {
  const StepFlow({super.key, required this.steps, required this.onFin…

class ChatMessage {
  const ChatMessage(this.text, this.sentAt, {required this.mine});
  final String text;
  final DateTime sentAt;
  final bool mine;
}
class ChatView extends StatelessWidget {
  const ChatView({super.key, required this.messages});
  final List<ChatMessage> messages; // oldest first

class CartLine {
  CartLine({required this.id, required this.name, required this.unitC…
  final String id;
  final String name;
  final int unitCents; // money as integer minor units, never double
  int qty;
  int get totalCents => unitCents * qty;
}
class CartModel extends ChangeNotifier {