Flutter SearchDelegate:如何删除文本下划线和文本下方的蓝线(颜色)？

class CustomSearchDelegate extends SearchDelegate {
  @override
  ThemeData appBarTheme(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    return theme.copyWith(
      // 修改文本样式
      textTheme: TextTheme(
        headline6: TextStyle(
          fontSize: 18,
          fontWeight: FontWeight.bold,
          color: Colors.black,
        ),
      ),
      // 修改TextField样式
      inputDecorationTheme: InputDecorationTheme(
        hintStyle: TextStyle(color: Colors.grey),
        border: InputBorder.none, // 隐藏下划线
        enabledBorder: InputBorder.none, // 隐藏蓝线
      ),
    );
  }

  @override
  Widget buildSuggestions(BuildContext context) {
    // 搜索建议页面的构建逻辑
    // ...
  }

  @override
  Widget buildResults(BuildContext context) {
    // 搜索结果页面的构建逻辑
    // ...
  }
}