an example for stream provider

stream_provider_example.dart

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

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Flutter Demo Home Page'),
        ),
        body: const Center(
          child: WidgetTop(),
        ),
      ),
    );
  }
}

class WidgetTop extends StatelessWidget {
  const WidgetTop({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return StreamProvider<List<int>>(
      create: (context) => numberStream(),
      initialData: const [0],
      child: const WidgetBottom(),
    );
  }
}

class WidgetBottom extends StatelessWidget {
  const WidgetBottom({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final data = context.watch<List<int>>();
    return Text(data.map((e) => e.toString()).reduce((value, element) => value + ',' + element));
  }
}

// fake data stream
Stream<List<int>> numberStream() async* {
  yield [0];
  for (var i = 1; i < 50; i++) {
    await Future.delayed(const Duration(seconds: 2));
    yield [1, 2, 3].map((e) => e + i).toList();
  }
}