如何在ExpansionTile展开颤动时更改文本默认颜色

class CustomTheme {
  static ThemeData getThemeData() {
    return ThemeData(
      // 在这里设置你想要的默认颜色
      textTheme: TextTheme(
        // 设置展开时的文本颜色
        subtitle1: TextStyle(color: Colors.red),
        // 设置折叠时的文本颜色
        subtitle2: TextStyle(color: Colors.blue),
      ),
    );
  }
}

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: CustomTheme.getThemeData(), // 应用自定义主题
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('ExpansionTile Demo'),
      ),
      body: ListView(
        children: <Widget>[
          ExpansionTile(
            title: Text('Title'),
            children: <Widget>[
              ListTile(
                title: Text('Subitem 1'),
              ),
              ListTile(
                title: Text('Subitem 2'),
              ),
            ],
          ),
        ],
      ),
    );
  }
}