Does it work with CustomScrollView and related SliverList? I wrapped the CustomScrollView with the LazyLoadScrollView, but I can only obtain the first pagination. After that the onEndOfPage method does not get called anymore.

Hi, I've used this plugin inside of a StreamBuilder without issues however when I try to use it inside a custom StatefulWidget the onEndOfPage callback gets called more than once.

Here the example app,

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart';
import 'package:lazy_load_scrollview/lazy_load_scrollview.dart';

main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(
        title: Text('LazyLoading'),
      ),
      body: Home(),
    ),
  ));
}

class Home extends StatefulWidget {
  final int pageSize;

  Home({this.pageSize = 10});

  @override
  State<StatefulWidget> createState() => HomeState();
}

class HomeState extends State<Home> {
  List<Map> documents;
  bool loading;
  int currentPage;
  Client client;

  @override
  void initState() {
    super.initState();
    documents = [];
    loading = false;
    currentPage = 0;
    client = Client();
    () async {
      await _loadMore();
    }();
  }

// 'http://monster6.disco.unimib.it/API/documents/search/?s=informatica&paging=${widget.pageSize}&offset=${currentPage > 0 ? currentPage * widget.pageSize : ''}'
  Future<void> _loadMore() async {
    print('loading more!');
    setState(() {
      loading = true;
    });
    final response = await client.get(
      Uri.http(
        'monster6.disco.unimib.it',
        '/API/documents/search',
        {
          's': 'informatica',
          'paging': '${widget.pageSize}',
          'offset':
              currentPage > 0 ? '${currentPage * widget.pageSize + 1}' : null
        },
      ),
    );
    print(jsonDecode(response.body));
    final results = List<Map>.from(
        jsonDecode(response.body)['documentsAleph']['documents']);
    if (mounted) {
      setState(() {
        loading = false;
        documents.addAll(results);
        currentPage++;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: <Widget>[
        Positioned.fill(
          child: LazyLoadScrollView(
            child: ListView.builder(
              itemCount: documents.length,
              itemBuilder: (context, index) {
                return AspectRatio(
                  aspectRatio: 2,
                  child: Card(
                    child: Text(documents[index]['title'] ?? 'null'),
                  ),
                );
              },
            ),
            onEndOfPage: () {
              _loadMore();
            },
            scrollOffset: 600,
          ),
        ),
        Positioned(
          top: 0,
          left: 0,
          right: 0,
          child: loading ? LinearProgressIndicator() : Container(),
        ),
      ],
    );
  }
}

RfreshIndicator stops working when LazyLoadScrollView is added to the tree. This makes it really inconvenient as Most ListViews fetching data have a RefreshIndicator. It would be nice if RehreshIndicator still works with LazyLoad

Hey there, recently I've been working on this package.. and I tried to put my ListView.builder inside the LazyLoadScrollView, OK that's worked fine. BUT... when I tried to wrap my ListView.builder by RefreshIndicator it gives me an error and that because the child accepts only ScrollView Widget...

.
.
.
.
// rest of the code

            return LazyLoadScrollView(
              onEndOfPage: () {
                BlocProvider.of<FetchProductsBloc>(context).add(
                  FetchProducts(count: 20),
                );
              },
              child: ListView.builder(
                itemCount: state.count,
                itemBuilder: (context, index) {
                  return ListTile(
                    title: Text('Loaded Data $index'),
                  );
                },
              ),
            );
.
.
.
.

HOW can I wrap the (listview with lazy load scrollview) with a refresh indicator too?? Any solutions??

this is how my widget tree looks

LazyLoadScrollView(
onEndOfPage: ( ) { }
child: SingleChildScrollView(      //vertical scroll view

child : Column( 
. . . . . 
CarouselSlider (                         //horizontalScrollview
. . . . . 
),
),);

onEndOfPage gets triggered for horizontal scroll view too which is not ideal for pagination, which is what I'm using it for, I tried using different scorllControllers, but nothing seems to be working, Is there any way I can make this work, or can this be implemented in the package?

Thanks.

When scrolling and reaches the bottom, does infinite loop calls. Should verify if position.pixels == position.maxScrollExtent and if true do another call.

This change makes the use of RefreshIndicator with LazyLoadScrollView possible.

E.g.

LazyLoadScrollView(
      onEndOfPage: () {
        //...
      },
      child: RefreshIndicator(
        onRefresh: () async {
          print('On refresh');
          return;
        },
        child: ListView.builder(
            //...
            ),
      ),
    );

In Flutter Android everything is fine. But I tested it on a small Flutter Web project and the package didn't work. Do you have any special configuration?

Hello ! I didn't know of the existence of this package and ended up creating listview notifier similar to this but slightly different. In any case, I'd like to offer it up as a PR. To improve I took both my ideas and your ideas and kind of squashed them together as well as implemented a few things from the issues here.

Here are a few things the new:

• lazyloadscrollview takes an optional ScrollController now that will work in place of bubbling notifier events (this is useful to avoid predicates)
• Added notificationPredicate #15
• Added an example on how to add animation when reached the end #2
• lazyloadscrollview can now work in both directions of a listview
• Added debounce timer that will prevent the callback from firiing a bunch of times

Breaking change:

• the lazyloadscrollview takes a builder instead of a child. This builder passes through isLoadingBefore and isLoadingAfter that tell the user when the respective async op is running.
• Renamed onEndOfPage to to onLoadAfter

I'd love to get your opinion on this big change. Leaving it as a draft for now

Hi please can you add a level depth check into _onNotifcation method. If you have a list with animated widget that scroll vertically this method is calle endlessly and also _loadMore.

The changes to do are these: At row 61 of lazy_load_scrollview.dart

if (widget.scrollDirection == notification.metrics.axis) {

should turn into

if (widget.scrollDirection == notification.metrics.axis && defaultScrollNotificationPredicate(notification)) {

This check if the scroll came from the real list scroll and not from a scrollable item into it.

Regards Massimo