[Flutter tips] Themeで囲ってデフォルトのアイコンサイズを変える

main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return MaterialApp(
      title: 'Test',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Card(
        child: Column(
          children: [
            const Text('Default icon size.'),
            const Icon(Icons.usb),
            const SizedBox(height: 16),
            // Themeで囲って、デフォルトのアイコンサイズを変える
            const Text('Change default icon size.'),
            Theme(
              data: theme.copyWith(iconTheme: theme.iconTheme.copyWith(size: 48)),
              child: const Icon(Icons.usb),
            ),
          ],
        ),
      ),
    );
  }
}