Mastering Pagination in Flutter: From ListView to Infinite Scroll with API Integration

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Handling large datasets efficiently is crucial in Flutter apps to enhance performance and ensure a smooth user experience. Pagination not only optimizes resource usage but also significantly boosts app responsiveness, especially when working with large APIs. Let's explore different pagination methods, complete with real-world examples and performance tips, to elevate your Flutter development skills.

🔹 Why Pagination Matters?

Imagine loading thousands of items from an API at once — your app would lag, causing frustration for users. Pagination addresses this by fetching data in smaller, manageable chunks, greatly improving app performance and user satisfaction.

Let's dive into various pagination techniques:

🔹 Manual Pagination with ListView.builder and ScrollController

Detect Scroll End

final ScrollController _scrollController = ScrollController();
@override
void initState() {
  super.initState();
  _scrollController.addListener(() {
    if (_scrollController.position.pixels >=
        _scrollController.position.maxScrollExtent) {
      fetchNextPage();
    }
  });
}

Fetch Next Page

Future<void> fetchNextPage() async {
  setState(() => isLoading = true);
  final response = await http.get(Uri.parse('https://dummyapi.io/items?page=$currentPage'));
  if (response.statusCode == 200) {
    final newItems = jsonDecode(response.body);
    setState(() {
      items.addAll(newItems);
      currentPage++;
      isLoading = false;
    });
  }
}

Loading Indicators and Edge Cases

ListView.builder(
  controller: _scrollController,
  itemCount: items.length + 1,
  itemBuilder: (context, index) {
    if (index == items.length) {
      return isLoading ? Center(child: CircularProgressIndicator()) : SizedBox();
    }
    return ListTile(title: Text(items[index].title));
  },
);

🔹 Using PagedListView from infinite_scroll_pagination

The infinite_scroll_pagination package simplifies pagination:

final PagingController<int, Product> _pagingController =
    PagingController(firstPageKey: 1);
@override
void initState() {
  super.initState();
  _pagingController.addPageRequestListener((pageKey) => fetchProducts(pageKey));
}
Future<void> fetchProducts(int page) async {
  final newItems = await fetchProductsFromAPI(page);
  final isLastPage = newItems.length < pageSize;
  if (isLastPage) {
    _pagingController.appendLastPage(newItems);
  } else {
    _pagingController.appendPage(newItems, page + 1);
  }
}

🔹 Using GetX for Pagination

GetX provides efficient state management for pagination:

class PostController extends GetxController {
  var posts = <Post>[].obs;
  int page = 1;
  var isLoading = false.obs;

void loadPosts() async {
    if (isLoading.value) return;
    isLoading(true);
    var newPosts = await Api.fetchPosts(page);
    posts.addAll(newPosts);
    page++;
    isLoading(false);
  }
}

🔹 Cursor-Based vs Offset-Based Pagination

FeatureOffset-BasedCursor-BasedPerformanceSlower on large datasetsEfficient, fasterComplexityEasier setupSlightly more complexReliabilityRisk of duplicatesStable and reliable

// 💡 Note: Cursor-based pagination excels for real-time or dynamic datasets.

🔹 Infinite Scrolling with Pull-to-Refresh

Enhance UX by combining infinite scrolling and pull-to-refresh:

RefreshIndicator(
  onRefresh: () async {
    items.clear();
    currentPage = 1;
    await fetchNextPage();
  },
  child: ListView.builder(
    controller: _scrollController,
    itemCount: items.length,
    itemBuilder: (_, index) => ListTile(title: Text(items[index])),
  ),
);

// 🔥 Pro Tip: Add shimmer loaders for a premium feel:

Shimmer.fromColors(
  child: Container(color: Colors.grey[300]),
  baseColor: Colors.grey[300]!,
  highlightColor: Colors.grey[100]!,
);

🔹 Performance Tips & Gotchas

• Memoize Data: Avoid repeated API calls by caching responses.
• Reduce Widget Rebuilds: Use const, efficient keys, and state management smartly.
• Choose Widgets Wisely: Opt for ListView.separated or SliverList for smoother scrolling.

🔹 Conclusion

Pagination methods vary based on your app's complexity and needs:

• Simple Apps: Manual pagination
• Intermediate/Advanced Apps:infinite_scroll_pagination or state management tools like GetX

We'd love to hear your experience. Which pagination approach do you prefer and why? Share your thoughts in the comments below!