Infinite Scroll Widget + Algolia + FlutterFlow

infiniteScrollWidget.dart

// Automatic FlutterFlow imports
import '../../backend/backend.dart';
import '../../flutter_flow/flutter_flow_theme.dart';
import '../../flutter_flow/flutter_flow_util.dart';
import '../widgets/index.dart'; // Imports other custom widgets
import '../actions/index.dart'; // Imports custom actions
import '../../flutter_flow/custom_functions.dart'; // Imports custom functions
import 'package:flutter/material.dart';
// Begin custom widget code
// DO NOT REMOVE OR MODIFY THE CODE ABOVE!

//import 'index.dart'; // Imports other custom widgets
import 'package:provider/provider.dart';

import 'dart:convert';
import 'package:around/components/user_post_card_widget.dart';
import '../../flutter_flow/custom_functions.dart' as functions;

import 'package:http/http.dart' as http;

import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';

class CustomPostList extends StatefulWidget {
  const CustomPostList(
      {Key? key,
      this.width = double.infinity,
      this.height = double.infinity,
      this.strokeWidth = 2})
      : super(key: key);

  final double width;
  final double height;
  final double strokeWidth;
  // final String location;
  // final String searchQuery;
  // final int radius;
  @override
  _CustomPostListState createState() => _CustomPostListState();
}

class _CustomPostListState extends State<CustomPostList> {
  ValueNotifier<String> _searchQuery =
      ValueNotifier<String>(FFAppState().postsearch);
  ValueNotifier<String> _location =
      ValueNotifier<String>(FFAppState().searchLocation);
  ValueNotifier<int> _radius = ValueNotifier<int>(FFAppState().searchRadius);

  static const _pageSize = 10;
  final PagingController<int, Post> _pagingController =
      PagingController(firstPageKey: 0);

  @override
  void initState() {
    _pagingController.addPageRequestListener((pageKey) {
      _fetchPage(pageKey);
    });

    _searchQuery.addListener(() => {_pagingController.refresh()});
    _location.addListener(() => {_pagingController.refresh()});
    _radius.addListener(() => {_pagingController.refresh()});

    super.initState();
  }

  Future<List<Post>> fetch(page) async {
    List<Post> posts = [];
    var url = "https://<your-algolia-app-id>-dsn.algolia.net/1/indexes/userposts/query";

    final response = await http.post(Uri.parse(url),
        body: jsonEncode({
          "params":
              "hitsPerPage=${_pageSize}&page=${page}&query=${FFAppState().postsearch}&aroundLatLng=${FFAppState().searchLocation}&aroundRadius=25000"
        }),
        headers: {
          'X-Algolia-API-Key': '<your-algolia-api-key>',
          'X-Algolia-Application-Id': '<your-algolia-app-id>'
        });

    if (response.statusCode == 200) {
      Map<String, dynamic> jsonMap = json.decode(response.body);
      (jsonMap['hits'] as List).forEach((x) => {posts.add(Post.fromJson(x))});
      return posts;
    } else {
      //throw Exception('Failed to load posts');
      return posts;
    }
  }

  Future<void> _fetchPage(int pageKey) async {
    try {
      double page = pageKey / _pageSize;

      List<Post> newItems = await fetch(page);
      print(newItems.length);
      final isLastPage = newItems.length < _pageSize;
      if (isLastPage) {
        _pagingController.appendLastPage(newItems);
      } else {
        final nextPageKey = pageKey + newItems.length;
        _pagingController.appendPage(newItems, nextPageKey);
      }
    } catch (error) {
      _pagingController.error = error;
    }
  }

  @override
  Widget build(BuildContext context) {
    context.watch<FFAppState>();

    _searchQuery.value = FFAppState().postsearch;
    _location.value = FFAppState().searchLocation;
    _radius.value = FFAppState().searchRadius;
    return PagedListView<int, Post>(
        pagingController: _pagingController,
        builderDelegate: PagedChildBuilderDelegate<Post>(
          itemBuilder: (context, item, index) => UserPostCardWidget(
              postRef: functions.getUserPostsDocRef(item.objectId)),
        ));
  }

  @override
  void dispose() {
    _pagingController.dispose();
    super.dispose();
  }
}

class Post {
  final String objectId;

  const Post({required this.objectId});

  factory Post.fromJson(Map<String, dynamic> json) {
    return Post(objectId: json['objectID']);
  }
}

You should reach out to FF support.. I ditched it, as like these there were many instances where I needed help and very little of it was available.. The FF support experience was average too throughout! Its much easier and faster to develop with VSC and few Flutter plugins there (along with FF used just to build the UI)