とりあえず WearOS で動くアプリを作ってみる（ついでにスマートウォッチをWebサーバにしてみる） #Flutter – Qiita

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_debouncer/flutter_debouncer.dart';
import 'package:wearable_rotary/wearable_rotary.dart';
import 'dart:async';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        brightness: Brightness.dark,
        textTheme: const TextTheme(
          displayLarge: TextStyle(
            fontSize: 48,
            fontWeight: FontWeight.bold,
            color: Colors.white,
          ),
        ),
      ),
      home: const CounterScreen(),
    );
  }
}

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

  @override
  StateCounterScreen> createState() => _CounterScreenState();
}

class _CounterScreenState extends StateCounterScreen> {
  int _counter = 0;
  StreamSubscriptionRotaryEvent>? _rotarySubscription;
  final _throttler = Throttler();

  Color _currentColor = Colors.white;
  Color _backgroundColor = Colors.black;
  Timer? _colorResetTimer;

  @override
  void initState() {
    super.initState();
    _setupRotaryInput();
  }

  @override
  void dispose() {
    _rotarySubscription?.cancel();
    _colorResetTimer?.cancel();
    super.dispose();
  }

  void _setupRotaryInput() {
    _rotarySubscription = rotaryEvents.listen((RotaryEvent event) {
      _throttler.throttle(
        duration: Duration(milliseconds: 200),
        onThrottle: () {
          _handleRotaryEvent(event);
        },
      );
    });
  }

  void _handleRotaryEvent(RotaryEvent event) {
    if (event.direction == RotaryDirection.clockwise) {
      _incrementCounter();
      return;
    }
    if (event.direction == RotaryDirection.counterClockwise) {
      _decrementCounter();
      return;
    }
  }

  void _incrementCounter() {
    setState(() {
      _counter++;
      _currentColor = Colors.white;
      _backgroundColor = Colors.green;
      _triggerHapticFeedback();
      _resetColorAfterDelay();
    });
  }

  void _decrementCounter() {
    setState(() {
      if (_counter > 0) {
        _counter--;
        _currentColor = Colors.white;
        _backgroundColor = Colors.red;
        _triggerHapticFeedback();
        _resetColorAfterDelay();
      }
    });
  }

  void _resetColorAfterDelay() {
    _colorResetTimer?.cancel();
    _colorResetTimer = Timer(const Duration(milliseconds: 200), () {
      if (mounted) {
        setState(() {
          _currentColor = Colors.white;
          _backgroundColor = Colors.black;
        });
      }
    });
  }

  void _triggerHapticFeedback() {
    HapticFeedback.lightImpact();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: AnimatedContainer(
        duration: const Duration(milliseconds: 200),
        curve: Curves.easeInOut,
        color: _backgroundColor,
        child: GestureDetector(
          behavior: HitTestBehavior.opaque,
          child: Center(
            child: AnimatedDefaultTextStyle(
              duration: const Duration(milliseconds: 200),
              style: TextStyle(
                color: _currentColor,
                fontSize: MediaQuery.of(context).size.width * 0.4,
                fontWeight: FontWeight.bold,
              ),
              child: Text('$_counter', textAlign: TextAlign.center),
            ),
          ),
        ),
      ),
    );
  }
}