Flutter vs .NET MAUI 比較

// Dart - Flutterカウンターウィジェット(StatefulWidget + ホットリロードで即座にテスト可能)
import 'package:flutter/material.dart';

void main() => runApp(const CounterApp());

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Counter Demo',
      theme: ThemeData(colorSchemeSeed: Colors.indigo, useMaterial3: true),
      home: const CounterPage(),
    );
  }
}

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

  @override
  State<CounterPage> createState() => _CounterPageState();
}

class _CounterPageState extends State<CounterPage> {
  int _count = 0;

  void _increment() {
    setState(() => _count++);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Flutter Counter')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text('You tapped this many times:'),
            Text('$_count', style: Theme.of(context).textTheme.headlineMedium),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _increment,
        child: const Icon(Icons.add),
      ),
    );
  }
}

// C# - .NET MAUI MauiProgram.cs(依存性注入 + フォント設定)
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using Microsoft.Extensions.Logging;

namespace CounterDemo;

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            });

        // サービスは同じBCL上に:EF Core/Azure SDKもここで参照可能
        builder.Services.AddSingleton<MainPage>();
        builder.Services.AddSingleton<CounterViewModel>();

#if DEBUG
        builder.Logging.AddDebug();
#endif

        return builder.Build();
    }
}

// CounterViewModel.cs - XAML Hot Reloadはこのファイルをカバーしない;C#の編集は
// .NET Hot Reloadで適用される(Visual Studio 2022、F5でデバッガ接続時)
public partial class CounterViewModel : ObservableObject
{
    [ObservableProperty]
    private int count;

    [RelayCommand]
    private void Increment() => Count++;
}