loris/lib/pages/timeline/timeline.dart

import 'package:flutter/material.dart';
import 'package:localization/localization.dart';
import 'package:loris/partials/thread.dart';
import '../../business_logic/timeline/timeline.dart' as tl;

class Timeline extends StatefulWidget {
  const Timeline({Key? key}) : super(key: key);
  @override
  State<Timeline> createState() => _TimelineState();
}

class _TimelineState extends State<Timeline> {
  String? id;
  final controller = ScrollController();
  List<Widget> children = [];
  bool loading = false;

  @override
  void initState() {
    super.initState();
    fetchMore();
    controller.addListener(() {
      if (controller.position.maxScrollExtent <= controller.offset &&
          !loading) {
        fetchMore();
      }
    });
  }

  Future fetchMore() async {
    loading = true;

    final model = await tl.getTimelineFromServer(id);
    id = model.posts[model.posts.length - 1].id;

    setState(() {
      if (children.isNotEmpty) {
        children.removeAt(children.length - 1);
      }
      children.addAll([
        Thread(
          model: model,
        )
      ]);
      children.add(
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextButton.icon(
              onPressed: () {
                fetchMore();
              },
              icon: const Icon(Icons.more_horiz),
              label: Text("load-more".i18n()),
            )
          ],
        ),
      );
      loading = false;
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      physics: const AlwaysScrollableScrollPhysics(),
      controller: controller,
      itemBuilder: (context, index) {
        return children[index];
      },
      separatorBuilder: (context, index) {
        return const Divider(
          color: Colors.transparent,
        );
      },
      itemCount: children.length,
      padding: const EdgeInsets.fromLTRB(24, 0, 24, 64),
      addAutomaticKeepAlives: false,
    );
  }
}