// 创建searchResultVC
let searchResultVC = UIViewController()
// 设置背景颜色为红色
searchResultVC.view.backgroundColor = UIColor.red
let searchController = UISearchController(searchResultsController: searchResultVC)
// 设置背景颜色
searchController.view.backgroundColor = UIColor (red: 0.97, green: 0.97, blue: 0.97, alpha: 1.0)
// 默认为YES,设置开始搜索时背景显示与否
// searchController.dimsBackgroundDuringPresentation = false
// 默认为YES,控制搜索时，是否隐藏导航栏
// searchController.hidesNavigationBarDuringPresentation = false
// 将搜索框视图设置为tableView的tableHeaderView
tableView.tableHeaderView = searchController.searchBar

// 搜索框
let bar = searchController.searchBar
// 样式
bar.barStyle = .default
// 设置光标及取消按钮的颜色
bar.tintColor = RGBA(r: 0.12, g: 0.74, b: 0.13, a: 1.00)
// 设置代理
bar.delegate = self

// 去除背景及上下两条横线
bar.setBackgroundImage(UIImage(), for: .any, barMetrics: .default)

// 右侧语音
bar.showsBookmarkButton = true
bar.setImage(#imageLiteral(resourceName: "VoiceSearchStartBtn"), for: .bookmark, state: .normal)
监听语音按钮的点击
// MARK:- UISearchBarDelegate
extension LXFContactViewController: UISearchBarDelegate {
  func searchBarBookmarkButtonClicked(_ searchBar: UISearchBar) {
    LXFLog("点击了语音按钮")
  }
}