ios - 自定义 navigationItem 的 searchController，但不适用于 iOS 11

Question

UISearchController iOS 11 customization这个问题我已经搜索过了，但是评论里的方法都帮不了我，所以我想再问一遍。

我使用以下代码设置搜索栏的外观。

扩展 UISearchBr 以获取 textField 和 placeHolderLabel:

extension UISearchBar{

    var textField: UITextField?{
        if let textField = self.value(forKey: "searchField") as? UITextField {

           return textField
        }
        return nil
    }

    var placehloderLabel:UILabel?{

        if let placeholderLabel = textField?.value(forKey: "placeholderLabel") as? UILabel{
            return placeholderLabel
    }
        return nil
    }
}

自定义 UISearchController 的子类:

class CustomSearchController:UISearchController{

    override init(searchResultsController: UIViewController?) {

        super.init(searchResultsController: searchResultsController)
        self.definesPresentationContext = true
        self.dimsBackgroundDuringPresentation = false
        self.hidesNavigationBarDuringPresentation = true
        self.searchBar.searchBarStyle = .minimal

        self.searchBar.placeholder = "搜索歌单内歌曲"
        self.searchBar.textField?.textColor = UIColor.white
        self.searchBar.placehloderLabel?.textColor = .white
        self.searchBar.placehloderLabel?.font = UIFont.systemFont(ofSize: 15)

    }

设置 prefersLargeTitles UINavigationBar.appearance().prefersLargeTitles = true

如果navigationItem.searchController = searchController结果如下(searchBar的外观不会发生变化):

但是如果我设置 navigationItem.titleView = searchController.searchBar，它会:

Does the iOS 11 permit developers to change the searchBar's appearance?If yes,I wonder how to customize it ?Any point is appreciated.Thanks!

Answer 1

Working with color and UINavigationItem's search controller

这段代码在 AppDelegate 类中。

UISearchBar.appearance().tintColor = UIColor(named: "Button") // using this to set the text color of the 'Cancel' button since the search bar ignores the global tint color property for some reason

if #available(iOS 11.0, *) {

      // Search bar placeholder text color
      UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).attributedPlaceholder = NSAttributedString(string: "Search", attributes: [NSForegroundColorAttributeName: UIColor.white])

     // Search bar text color
      UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).defaultTextAttributes = [NSForegroundColorAttributeName: UIColor.red]

     // Insertion cursor color
      UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).tintColor = UIColor.red

        } else {
            // Fallback on earlier versions
        }

   // Search bar clear icon
      UISearchBar.appearance().setImage(UIImage(named: "clear"), for: .clear, state: .normal)