UISearchBar覆蓋清除刷新並停止類似於Safari瀏覽器地址欄

Question

如何自定義UISearchBar的行爲清除按鈕以顯示刷新和停止與iOS Safari地址欄類似的圖標和功能。我試圖讓的UITextField的保持，但它返回nil

extension UISearchBar { 
func textFiled() -> UITextField? { 
    for view in self.subviews as [UIView] { 
     if let textField = view as? UITextField { 
      return textField 
     } 
    } 
    return nil 
} 
} 

Answer 1

extension UISearchBar { 
    var textField: UITextField? { 
     if let textField:UITextField = self.valueForKey("_searchField") as? UITextField { 
      return textField 
     } 
     return nil 
    } 
} 

[中的UISearchBar的自定義的UITextField - iOS設備]的