adguard-home-manager/lib/widgets/tab_content_list.dart

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

import 'package:adguard_home_manager/providers/app_config_provider.dart';
import 'package:adguard_home_manager/constants/enums.dart';

class CustomTabContentList extends StatelessWidget {
  final Widget Function() loadingGenerator;
  final int itemsCount;
  final Widget Function(int index) contentWidget;
  final Widget noData;
  final Widget Function() errorGenerator;
  final LoadStatus loadStatus;
  final Future<void> Function() onRefresh;
  final double? refreshIndicatorOffset;
  final Widget? fab;
  final bool? fabVisible;
  final bool? noSliver;

  const CustomTabContentList({
    Key? key,
    required this.loadingGenerator,
    required this.itemsCount,
    required this.contentWidget,
    required this.noData,
    required this.errorGenerator,
    required this.loadStatus,
    required this.onRefresh,
    this.refreshIndicatorOffset,
    this.fab,
    this.fabVisible, 
    this.noSliver
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final appConfigProvider = Provider.of<AppConfigProvider>(context);

    switch (loadStatus) {
      case LoadStatus.loading:
        if (noSliver == true) {
          return Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: loadingGenerator()
          );
        }
        else {
          return SafeArea(
            top: false,
            bottom: false,
            child: Builder(
              builder: (BuildContext context) => CustomScrollView(
                slivers: [
                  SliverOverlapInjector(
                    handle: NestedScrollView.sliverOverlapAbsorberHandleFor(context),
                  ),
                  SliverFillRemaining(
                    child: Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 16),
                      child: loadingGenerator()
                    ),
                  )
                ],
              ),
            )
          );
        }
        
        
      case LoadStatus.loaded:
        if (noSliver == true) {
          if (itemsCount > 0) {
            return Stack(
              children: [
                ListView.builder(
                  itemCount: itemsCount,
                  itemBuilder: (context, index) => contentWidget(index),
                ),
                if (fab != null) AnimatedPositioned(
                  duration: const Duration(milliseconds: 100),
                  curve: Curves.easeInOut,
                  bottom: fabVisible != null && fabVisible == true ?
                    appConfigProvider.showingSnackbar
                      ? 70 : 20
                    : -70,
                  right: 20,
                  child: fab!
                ),
              ],
            );
          }
          else {
            return Stack(
              children: [
                noData,
                if (fab != null) AnimatedPositioned(
                  duration: const Duration(milliseconds: 100),
                  curve: Curves.easeInOut,
                  bottom: fabVisible != null && fabVisible == true ?
                    appConfigProvider.showingSnackbar
                      ? 70 : 20
                    : -70,
                  right: 20,
                  child: fab!
                ),
              ],
            );
          }
        }
        else {
          return Stack(
            children: [
              SafeArea(
                top: false,
                bottom: false,
                child: Builder(
                  builder: (BuildContext context) {
                    return RefreshIndicator(
                      onRefresh: onRefresh,
                      edgeOffset: refreshIndicatorOffset ?? 95,
                      child: CustomScrollView(
                        slivers: <Widget>[
                          SliverOverlapInjector(
                            handle: NestedScrollView.sliverOverlapAbsorberHandleFor(context),
                          ),
                          if (itemsCount > 0) SliverList(
                            delegate: SliverChildBuilderDelegate(
                              (context, index) => contentWidget(index),
                              childCount: itemsCount
                            ),
                          ),
                          if (itemsCount == 0) SliverFillRemaining(
                            child: noData,
                          )
                        ],
                      ),
                    );
                  },
                ),
              ),
              if (fab != null) AnimatedPositioned(
                duration: const Duration(milliseconds: 100),
                curve: Curves.easeInOut,
                bottom: fabVisible != null && fabVisible == true ?
                  appConfigProvider.showingSnackbar
                    ? 70 : 20
                  : -70,
                right: 20,
                child: fab!
              ),
            ],
          );
        }

      case LoadStatus.error: 
        if (noSliver == true) {
          return Padding(
            padding: const EdgeInsets.only(
              top: 95,
              left: 16,
              right: 16
            ),
            child: errorGenerator()
          );
        }
        else {
          return SafeArea(
            top: false,
            bottom: false,
            child: Builder(
              builder: (BuildContext context) => CustomScrollView(
                slivers: [
                  SliverOverlapInjector(
                    handle: NestedScrollView.sliverOverlapAbsorberHandleFor(context),
                  ),
                  SliverFillRemaining(
                    child: Padding(
                      padding: const EdgeInsets.only(
                        top: 95,
                        left: 16,
                        right: 16
                      ),
                      child: errorGenerator()
                    ),
                  )
                ],
              ),
            )
          );
        }
       
      default:
        return const SizedBox();
    }
  }
}