exquisite-snowflake-4839

readme.md

exquisite-snowflake-4839

Created with <3 with dartpad.dev.

main.dart

import 'dart:async';
import 'dart:math';

import 'package:flutter/material.dart';

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

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Streams Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Streams'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _futureValue = 0;

  late StreamSubscription subscription;

  void _startListen() {
    subscription = getRandomValues().listen((value) {
      setState(() {
        _futureValue = value;
      });
    });
  }

  void _stopListen() {
    subscription.cancel();
    setState(() {
      _futureValue = 0;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          backgroundColor: Theme.of(context).colorScheme.inversePrimary,
          title: Text(widget.title),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(
                '$_futureValue',
                style: Theme.of(context).textTheme.headlineMedium,
              ),
              ElevatedButton(
                child: const Text('Start Listening'),
                onPressed: () => _startListen(),
              ),
              ElevatedButton(
                child: const Text('Stop Listening'),
                onPressed: () => _stopListen(),
              ),
            ],
          ),
        ) // This trailing comma makes auto-formatting nicer for build methods.
        );
  }

  Stream<int> getRandomValues() async* {
    var random = Random();
    while (true) {
      await Future.delayed(const Duration(seconds: 1));
      yield random.nextInt(100);
    }
  }
}