builder_plus 1.1.4

A Flutter package for simplified async operations with built-in loading, error, and empty states management.

example/lib/main.dart

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

// A custom class to illustrate typing
typedef Id = int;

class Exemple {
  final Id id;
  final String nom;

  Exemple(this.id, this.nom);

  @override
  String toString() => 'Exemple(id: $id, nom: $nom)';
}

// Simulate an asynchronous operation on an Exemple
Future<Exemple> traiterExemple(Exemple exemple,
    {bool throwError = false, bool empty = false}) async {
  await Future.delayed(const Duration(seconds: 2));
  if (throwError) throw Exception('Network error');
  if (empty)
    return Future.value(Exemple(exemple.id, exemple.nom.toUpperCase()));
  return Exemple(exemple.id, exemple.nom.toUpperCase());
}

// Simulate a stream of operations on an Exemple
Stream<Exemple?> streamerExemple(Exemple exemple,
    {bool throwError = false, bool empty = false}) async* {
  yield null;
  await Future.delayed(const Duration(seconds: 1));
  if (throwError) throw Exception('Stream error');
  if (empty)
    yield null;
  else
    yield Exemple(exemple.id, exemple.nom.toUpperCase());
  await Future.delayed(const Duration(seconds: 1));
  yield Exemple(exemple.id, '${exemple.nom.toUpperCase()} (final)');
}

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'builder_plus Example',
      theme: ThemeData(primarySwatch: Colors.blue),
      home: const ExempleScreen(),
    );
  }
}

class ExempleScreen extends StatefulWidget {
  const ExempleScreen({super.key});

  @override
  State<ExempleScreen> createState() => _ExempleScreenState();
}

class _ExempleScreenState extends State<ExempleScreen> {
  bool throwFutureError = false;
  bool throwStreamError = false;
  bool showEmpty = false;

  @override
  Widget build(BuildContext context) {
    final exemple = Exemple(1, 'demo');
    return Scaffold(
      appBar: AppBar(title: const Text('FutureWorker & StreamWorker Example')),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Checkbox(
                  value: throwFutureError,
                  onChanged: (v) =>
                      setState(() => throwFutureError = v ?? false),
                ),
                const Text('Future Error'),
                const SizedBox(width: 16),
                Checkbox(
                  value: throwStreamError,
                  onChanged: (v) =>
                      setState(() => throwStreamError = v ?? false),
                ),
                const Text('Stream Error'),
                const SizedBox(width: 16),
                Checkbox(
                  value: showEmpty,
                  onChanged: (v) => setState(() => showEmpty = v ?? false),
                ),
                const Text('Empty State'),
              ],
            ),
            const SizedBox(height: 24),
            const Text('FutureWorker',
                style: TextStyle(fontWeight: FontWeight.bold)),
            FutureWorker<Exemple?>(
              future: traiterExemple(exemple,
                  throwError: throwFutureError, empty: showEmpty),
              builder: (context, resultat) => Text(
                'After processing: \n${resultat.toString()}',
                style: const TextStyle(fontSize: 18),
              ),
              loadingBuilder: (context) => const OptionLoading(size: 32),
              emptyBuilder: (context) => const OptionEmpty(
                text: 'No data received',
                icon: Icons.hourglass_empty,
              ),
              errorBuilder: (context, error) => OptionError(
                error: error.toString(),
                onRetry: () => setState(() {}),
                retryButtonText: 'Retry',
              ),
            ),
            const SizedBox(height: 32),
            const Text('StreamWorker',
                style: TextStyle(fontWeight: FontWeight.bold)),
            StreamWorker<Exemple?>(
              stream: streamerExemple(exemple,
                  throwError: throwStreamError, empty: showEmpty),
              builder: (context, resultat) => Text(
                'Stream: \n${resultat.toString()}',
                style: const TextStyle(fontSize: 18),
              ),
              loadingBuilder: (context) =>
                  const OptionLoading(size: 32, color: Colors.orange),
              emptyBuilder: (context) => const OptionEmpty(
                text: 'Empty stream',
                icon: Icons.stream,
                iconColor: Colors.orange,
              ),
              errorBuilder: (context, error) => OptionError(
                error: error.toString(),
                onRetry: () => setState(() {}),
                retryButtonText: 'Restart stream',
              ),
            ),
          ],
        ),
      ),
    );
  }
}