Movies Providers

Riverpod providers that manage paginated movie lists for now playing, popular, upcoming, top rated, and Mexican movies.

The movies providers expose paginated List<Movie> state using Riverpod’s NotifierProvider. Every list-based provider shares the same MoviesNotifier class and differs only in which repository method it calls.

Provider overview

Provider	Type	State	Repository method
nowPlayingMoviesProvider	NotifierProvider	List<Movie>	getNowPlaying
popularMoviesProvider	NotifierProvider	List<Movie>	getPopular
upcomingMoviesProvider	NotifierProvider	List<Movie>	getUpcoming
topratedMoviesProvider	NotifierProvider	List<Movie>	getTopRated
mexicanMoviesProvider	NotifierProvider	List<Movie>	getMexicanMovies
movieSlideShowProvider	Provider	List<Movie>	Derived — first 6 now-playing movies
intialLoadingProvider	Provider	bool	Derived — true while any list is empty

---

List providers

Each of the five list providers is declared with NotifierProvider and created with a MoviesNotifier that captures its specific fetch callback.

movies_providers.dart

// Type alias for any paginated movie fetch function
typedef MovieCallback = Future<List<Movie>> Function({int page});

final nowPlayingMoviesProvider = NotifierProvider<MoviesNotifier, List<Movie>>(
  () => MoviesNotifier((ref) => ref.watch(movieRepositoryProvider).getNowPlaying),
);

final popularMoviesProvider = NotifierProvider<MoviesNotifier, List<Movie>>(
  () => MoviesNotifier((ref) => ref.watch(movieRepositoryProvider).getPopular),
);

final upcomingMoviesProvider = NotifierProvider<MoviesNotifier, List<Movie>>(
  () => MoviesNotifier((ref) => ref.watch(movieRepositoryProvider).getUpcoming),
);

final topratedMoviesProvider = NotifierProvider<MoviesNotifier, List<Movie>>(
  () => MoviesNotifier((ref) => ref.watch(movieRepositoryProvider).getTopRated),
);

final mexicanMoviesProvider = NotifierProvider<MoviesNotifier, List<Movie>>(
  () => MoviesNotifier(
    (ref) => ref.watch(movieRepositoryProvider).getMexicanMovies,
  ),
);

---

Derived providers

movieSlideShowProvider

A read-only Provider<List<Movie>> that derives its value from nowPlayingMoviesProvider. It returns an empty list while now-playing movies are loading, otherwise it returns the first six entries for use in a hero slideshow.

movie_slideshow_provider.dart

final movieSlideShowProvider = Provider<List<Movie>>((ref) {
  final nowPlayingMovies = ref.watch(nowPlayingMoviesProvider);
  if (nowPlayingMovies.isEmpty) return [];
  return nowPlayingMovies.sublist(0, 6);
});

intialLoadingProvider

A read-only Provider<bool> that returns true as long as any of the five movie lists is still empty. Widgets use this to show a full-screen loading indicator before the first page of data arrives.

initialLoading_provider.dart

final intialLoadingProvider = Provider<bool>((ref) {
  final step1 = ref.watch(nowPlayingMoviesProvider).isEmpty;
  final step2 = ref.watch(upcomingMoviesProvider).isEmpty;
  final step3 = ref.watch(popularMoviesProvider).isEmpty;
  final step4 = ref.watch(topratedMoviesProvider).isEmpty;
  final step5 = ref.watch(mexicanMoviesProvider).isEmpty;

  if (step1 || step2 || step3 || step4 || step5) return true;
  return false;
});

---

MoviesNotifier

MoviesNotifier extends Riverpod’s Notifier<List<Movie>>. It accumulates pages of movies into its state list and guards against concurrent fetches with the isLoading flag.

movies_providers.dart

class MoviesNotifier extends Notifier<List<Movie>> {
  final MovieCallback Function(Ref ref) _callbackBuilder;
  late final MovieCallback fetchMoreMovies;

  MoviesNotifier(this._callbackBuilder);

  int currentPage = 0;
  bool isLoading = false;

  @override
  List<Movie> build() {
    fetchMoreMovies = _callbackBuilder(ref);
    return [];
  }

  Future<void> loadNextPage() async {
    if (isLoading) return;
    isLoading = true;

    currentPage++;
    final movies = await fetchMoreMovies(page: currentPage);

    state = [...state, ...movies];

    isLoading = false;
  }
}

Fields

currentPage · int · default: "0"

Tracks the last page number that was successfully fetched. Incremented before each API call inside loadNextPage().

isLoading · bool · default: "false"

Guard flag that prevents duplicate in-flight requests. Set to true at the start of loadNextPage() and back to false once the fetch completes.

Methods

build()

Called once by Riverpod when the notifier is first read. Resolves the fetchMoreMovies callback from the _callbackBuilder closure (which has access to ref) and returns an empty list as the initial state.

loadNextPage()

Appends the next page of movies to state. If a fetch is already in progress (isLoading == true), the call returns immediately. Otherwise it increments currentPage, awaits the API call, and spreads the results onto the existing state list.

---

Usage in a widget

Call loadNextPage() once on first build (or when the user scrolls to the bottom) by reading the notifier from ref.

home_screen.dart

// _HomeView is a ConsumerStatefulWidget defined inside home_screen.dart
class _HomeViewState extends ConsumerState<_HomeView> {
  @override
  void initState() {
    super.initState();
    // Load the first page of each category
    ref.read(nowPlayingMoviesProvider.notifier).loadNextPage();
    ref.read(popularMoviesProvider.notifier).loadNextPage();
    ref.read(topratedMoviesProvider.notifier).loadNextPage();
    ref.read(upcomingMoviesProvider.notifier).loadNextPage();
    ref.read(mexicanMoviesProvider.notifier).loadNextPage();
  }

  @override
  Widget build(BuildContext context) {
    // Show a loader until all lists have at least one page
    final initialLoading = ref.watch(intialLoadingProvider);
    if (initialLoading) return const FullscreenLoader();

    final nowPlayingMovies = ref.watch(nowPlayingMoviesProvider);
    final slideShowMovies  = ref.watch(movieSlideShowProvider);

    return CustomScrollView(
      slivers: [
        const SliverAppBar(floating: true, title: CustomAppbar()),
        SliverList(
          delegate: SliverChildBuilderDelegate(
            (context, index) {
              if (index > 0) return null;
              return Column(
                children: [
                  MovieSlideshow(movies: slideShowMovies),
                  MovieHorizontalListview(
                    movies: nowPlayingMovies,
                    title: 'En cines',
                    subTitle: 'Lunes 27 de Octubre',
                    loadNextPage: () =>
                        ref.read(nowPlayingMoviesProvider.notifier).loadNextPage(),
                  ),
                ],
              );
            },
            childCount: 1,
          ),
        ),
      ],
    );
  }
}

All providers are exported from lib/presentation/providers/providers.dart. Import that barrel file instead of individual provider files.