在我的tvOS应用程序中，我的搜索页面位于Search Bar顶部，Table View下有最终结果列表。
当我们关注searchBar并且用户按下Siri的语音时，结果会插入搜索栏（如预期的那样）。但是，当用户向下滚动搜索结果并且无法找到他们要查找的内容时，他们必须向上滚动（一直向上）到searchBar再次使用Siri。
如果用户在searchBar不在焦点时尝试使用Siri，全球Siri会开始在不同的应用中寻找结果（这不是我想要的）
如何在搜索页面上将searchBar设置为Siri的全局焦点？
说实话，我不知道该怎么做......
在AppDelegate.swift中调用一个函数来创建Search View Controller并将其添加到Tab Bar Controller。
我考虑过尝试preferedFocusView，但在阅读完文档之后，我怀疑它会起作用。
func configueSearchController() -> UIViewController {
let storyboard = UIStoryboard(name: "Search", bundle: nil)
guard let searchResultsController = storyboard.instantiateViewController(withIdentifier: SearchViewController.storyboardIdentifier) as? SearchViewController else {
fatalError("Unable to instatiate a SearchResultViewController from the storyboard.")
}
/*
Create a UISearchController, passing the `searchResultsController` to
use to display search results.
*/
let searchController = UISearchController(searchResultsController: searchResultsController)
searchController.searchResultsUpdater = searchResultsController
searchController.searchBar.placeholder = NSLocalizedString("Enter keyword (e.g. Gastric Bypass)", comment: "")
searchController.view.backgroundColor = Constants.Color.backgroundcolor
searchController.searchBar.keyboardAppearance = UIKeyboardAppearance.dark
searchController.searchBar.tintColor = Constants.Color.backgroundcolor
searchController.searchBar.backgroundColor = Constants.Color.backgroundSearchBarColor
searchController.searchBar.setTextColor(color: .white)
searchController.hidesNavigationBarDuringPresentation = false
searchController.obscuresBackgroundDuringPresentation = true
searchController.searchBar.searchBarStyle = .minimal
searchController.searchBar.sizeToFit()
searchController.searchBar.focus
//TODO: Check if this works
searchController.searchBar.accessibilityLanguage = "en"
//searchResultsController.tableView.tableHeaderView = searchController.searchBar
// Contain the `UISearchController` in a `UISearchContainerViewController`.
let searchContainer: UISearchContainerViewController = UISearchContainerViewController(searchController: searchController)
// Finally contain the `UISearchContainerViewController` in a `UINavigationController`.
let searchNavigationController = UINavigationController(rootViewController: searchContainer)
searchNavigationController.navigationBar.isTranslucent = true
searchNavigationController.navigationBar.tintColor = Constants.Color.backgroundcolor
searchNavigationController.tabBarItem.title = "Search"
return searchNavigationController
}