title: Is it possible to change Icon according to lightTheme or darkTheme in ThemeData? in flutter
body: <p>I want the icon to change and the boxshadow color to change when GestureDetecotr is pressed. hopefully it will be What should I do?</p>
  <p>In the current emulator, press the middle button to change the appearance.</p>
  <p><a href="https://i.stack.imgur.com/z4cnrl.png" rel="nofollow noreferrer">blackMode</a></p>
  <p><a href="https://i.stack.imgur.com/10U37l.png" rel="nofollow noreferrer">lightMode</a></p>
  <h3>home.dart part</h3>
  <pre class="lang-dart prettyprint-override"><code>              import 'package:flutter/material.dart';
  import 'package:neumorphism/theme/theme_service.dart';
  
  class Home extends StatelessWidget {
    const Home({Key? key}) : super(key: key);
  
    @override
    Widget build(BuildContext context) {
      bool _tapped = false;
      var _lightIcon = Icons.wb_sunny;
      var _blackIcon = Icons.dark_mode;
  
      return Scaffold(
        appBar: AppBar(
          title: Text('Neumorphism'),
        ),
        body: Center(
          child: GestureDetector(
              onTap: () {
                ThemeService().changeThemeMode();
              },
              child: Container(
                  width: 200,
                  height: 200,
                  decoration: BoxDecoration(
                      color: Colors.grey[300],
                      borderRadius: BorderRadius.all(
                        Radius.circular(40),
                      ),
                      boxShadow: [
                        BoxShadow(
                            color: Colors.grey.shade500,
                            offset: Offset(5.0, 5.0),
                            blurRadius: 15.0,
                            spreadRadius: 1.0),
                        BoxShadow(
                            color: Colors.white,
                            offset: Offset(-5.0, -5.0),
                            blurRadius: 15.0,
                            spreadRadius: 1.0),
                      ]),
                  child: Center(child: Icon(_lightIcon)))),
        ),
      );
    }
  }
  </code></pre>
  <h3>themes.dart</h3>
  <pre class="lang-dart prettyprint-override"><code>import 'package:flutter/material.dart';
  
  class Themes {
    final lightTheme = ThemeData.light().copyWith(
      primaryColor: Colors.grey[300],
      appBarTheme: AppBarTheme(
        brightness: Brightness.light,
      ),
      iconTheme: IconThemeData(color: Colors.white, size: 80),
    );
    final darkTheme = ThemeData.dark().copyWith(
      primaryColor: Colors.grey[800],
      appBarTheme: AppBarTheme(
        brightness: Brightness.dark,
      ),
      iconTheme: IconThemeData(
        color: Colors.black87,
        size: 80,
      ),
    );
  }
  
  </code></pre>
  <h3>theme_service.dart</h3>
  <p><a href="https://i.stack.imgur.com/oVppj.png" rel="nofollow noreferrer">theme_service.dart</a></p>