GetX - Sample ScrollMixin and Pagination

main.dart

import 'package:flutter/material.dart';
import 'package:get/get.dart';

void main() {
  runApp(GetMaterialApp(
    initialRoute: '/home',
    getPages: [
      GetPage(
        name: '/home',
        page: () => HomePage(),
      ),
      GetPage(
        name: '/git-repositories',
        page: () => GitRepositoryPage(),
        binding: GitRepositoryBinding(),
      ),
    ],
  ));
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('HOME')),
      body: Center(
        child: ElevatedButton(
          onPressed: () => Get.toNamed('/git-repositories'),
          child: Text('View GitHub Repositories'),
        ),
      ),
    );
  }
}

class GitRepositoryBinding extends Bindings {
  @override
  void dependencies() {
    Get.lazyPut(() => GitRepositoryProvider());
    Get.put(GitRepositoryController(provider: Get.find()));
  }
}

class GitRepositoryModel {
  GitRepositoryModel({
    required this.fullName,
    required this.description,
    required this.url,
  });

  String fullName;
  String description;
  String url;

  factory GitRepositoryModel.fromJson(Map<String, dynamic> json) =>
      GitRepositoryModel(
        fullName: json['full_name'],
        description: json['description'] ?? 'No description',
        url: json['html_url'],
      );

  static List<GitRepositoryModel> listFromJson(list) =>
      List<GitRepositoryModel>.from(
          list.map((x) => GitRepositoryModel.fromJson(x)));
}

class GitRepositoryController extends GetxController
    with StateMixin<List<GitRepositoryModel>>, ScrollMixin {
  final GitRepositoryProvider provider;
  GitRepositoryController({required this.provider});

  List<GitRepositoryModel> repositories = [];
  final int repositoriesPerPage = 10;
  int page = 1;
  bool getFirstData = false;
  bool lastPage = false;

  @override
  void onInit() {
    findAllGitRepositories();
    super.onInit();
  }

  Future<void> findAllGitRepositories() async {
    await provider.getGitRepositories(repositoriesPerPage, page).then((result) {
      final bool emptyRepositories = result.body?.isEmpty ?? true;
      if (!getFirstData && emptyRepositories) {
        change(null, status: RxStatus.empty());
      } else if (getFirstData && emptyRepositories) {
        lastPage = true;
      } else {
        getFirstData = true;
        repositories.addAll(result.body!);
        change(repositories, status: RxStatus.success());
      }
    }, onError: (err) {
      change(null, status: RxStatus.error(err.toString()));
    });
  }

  @override
  Future<void> onEndScroll() async {
    print('onEndScroll');
    if (!lastPage) {
      page += 1;
      Get.dialog(Center(child: LinearProgressIndicator()));
      await findAllGitRepositories();
      Get.back();
    } else {
      Get.snackbar('Alert', 'End of Repositories');
    }
  }

  @override
  Future<void> onTopScroll() async {
    print('onTopScroll');
  }
}

class GitRepositoryProvider extends GetConnect {
  final String org = 'flutter';

  @override
  void onInit() {
    // All request will pass to jsonEncode so CasesModel.fromJson()
    httpClient.defaultDecoder = GitRepositoryModel.listFromJson;
    httpClient.baseUrl = 'https://api.github.com/orgs';
  }

  Future<Response<List<GitRepositoryModel>>> getGitRepositories(
          int itemsPerPage, int page) =>
      get<List<GitRepositoryModel>>(
        '/$org/repos?per_page=$itemsPerPage&page=$page',
        // query: {'orderBy': 'nome'},
        decoder: GitRepositoryModel.listFromJson,
      );
}

class GitRepositoryPage extends GetView<GitRepositoryController> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text('Repositories')),
        body: Container(
          child: controller.obx(
            (state) => ListView.builder(
              controller: controller.scroll,
              itemCount: state?.length,
              itemBuilder: (context, index) {
                final GitRepositoryModel repository = state![index];
                return ListTile(
                  isThreeLine: true,
                  leading: Text(
                    (++index).toString(),
                    style: TextStyle(fontSize: 20),
                  ),
                  title: Text(repository.fullName),
                  subtitle:
                      Text('${repository.description}\n${repository.url}'),
                );
              },
            ),
            onLoading: Center(child: LinearProgressIndicator()),
            onEmpty: Center(
              child: Text(
                'Repositories no found',
                style: TextStyle(fontSize: 18),
                textAlign: TextAlign.center,
              ),
            ),
            onError: (error) => Center(
              child: Text(
                'Error: Cannot get repositories \n$error',
                style: TextStyle(fontSize: 18),
                textAlign: TextAlign.center,
              ),
            ),
          ),
        ));
  }
}