A declarative™ way to handle loading notifications with Widgets™

loading_notification_listener_route.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:material_theme/loading_notification/loading_image.dart';
import 'package:material_theme/loading_notification/loading_notification_listener.dart';
import 'package:material_theme/widgets/layout/default_scaffold.dart';

import 'loading_future_builder.dart';

class LoadingNotificationsRoute extends StatefulWidget {
  @override
  _LoadingNotificationsRouteState createState() =>
      _LoadingNotificationsRouteState();
}

class _LoadingNotificationsRouteState extends State<LoadingNotificationsRoute> {
  final _groupOne = {
    "1000": Duration(milliseconds: 1000),
    "1250": Duration(milliseconds: 1250),
    "1500": Duration(milliseconds: 1500),
    "1750": Duration(milliseconds: 1750),
  };

  bool _isLoading = true;

  void _handleLoaded() {
    print("Loaded!");
    setState(() {
      _isLoading = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    return DefaultScaffold(
      "/loading-notifications",
      child: LoadingNotificationListener(
        onLoaded: _handleLoaded,
        child: Column(
          children: [
            Text(_isLoading ? "All still loading..." : "All done!"),
            SizedBox(height: 16),

            /// Group One
            LoadingNotificationListener(
              key: Key("Group 1"),
              child: Column(
                children: <Widget>[
                  Text("FutureBuilders"),
                  ..._groupOne.entries.map<Widget>((e) {
                    return LoadingFutureBuilder<String>(
                      key: Key(e.key),
                      future:
                          Future<String>.delayed(e.value).then((_) => e.key),
                      initialData: "Loading...",
                      builder: (context, snap) {
                        return Text(snap.data ?? "Wat");
                      },
                    );
                  })
                ],
              ),
            ),

            SizedBox(height: 32),

            /// Images
            LoadingNotificationListener(
              key: Key("Images"),
              child: Column(
                children: <Widget>[
                  Text("Images"),
                  LoadingImage(
                    key: Key("Image 1"),
                    image: NetworkImage(
                      "https://upload.wikimedia.org/wikipedia/commons/4/4e/Pleiades_large.jpg",
                    ),
                  ),
                  LoadingImage(
                    key: Key("Image 2"),
                    image: NetworkImage(
                      "https://upload.wikimedia.org/wikipedia/commons/3/3d/LARGE_elevation.jpg",
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}