stream<t>-initial-value-in-flutter.dart

// Free Flutter Course 💙 https://linktr.ee/vandadnp
// Want to support my work 🤝? https://buymeacoffee.com/vandad

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_hooks/flutter_hooks.dart';

void main() {
  runApp(
    MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      debugShowCheckedModeBanner: false,
      home: const HomePage(),
    ),
  );
}

const url = 'https://bit.ly/3x7J5Qt';

class HomePage extends HookWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    late final StreamController<double> controller;
    controller = useStreamController<double>(onListen: () {
      controller.sink.add(0.0);
    });

    return Scaffold(
      appBar: AppBar(
        title: const Text('Home page'),
      ),
      body: StreamBuilder<double>(
          stream: controller.stream,
          builder: (context, snapshot) {
            if (!snapshot.hasData) {
              return const CircularProgressIndicator();
            } else {
              final rotation = snapshot.data ?? 0.0;
              return GestureDetector(
                onTap: () {
                  controller.sink.add(rotation + 10.0);
                },
                child: RotationTransition(
                  turns: AlwaysStoppedAnimation(rotation / 360.0),
                  child: Center(
                    child: Image.network(url),
                  ),
                ),
              );
            }
          }),
    );
  }
}