我现在正试着将 
 this转换成Swift而没有真正的背景. 
  
 
这是我到目前为止所得到的…而且我一直在寻找谷歌并不知道要搜索什么才能更具体.你能否详细说明我做错了什么?谢谢
更新:
我已经找到了objective-c标签,因此更多与此线程相关的人可能能够看到它并希望得到答案.
解决方法
 Michael Dautermann回答说得对,但是为了隐藏附件栏,你需要使用_NoInputAccessoryView类的inputAccessoryView()来调用UIView类的方法inputAccessoryView().我刚刚在代码中添加了几行额外的行来完成这个方法调配工作. 
  
 
        首先,你需要一个假类来交换
final class FauxBarHelper: NSObject {
    var inputAccessoryView: AnyObject? { return nil }
} 
 然后在控制器类中创建此方法
/// Removes the keyboard accessory view from the web view
/// Source: https://stackoverflow.com/a/32620344/308315 / https://stackoverflow.com/a/33939584/308315
func _removeInputAccessoryView(webView: UIWebView) {
    var targetView: UIView? = nil
    for view in webView.scrollView.subviews {
        if String(describing: type(of: view)).hasPrefix("WKContent") {
            targetView = view
        }
    }
    guard let target = targetView else { return }
    let noInputAccessoryViewClassName = "\(target.superclass!)_NoInputAccessoryView"
    var newClass: AnyClass? = NSClassFromString(noInputAccessoryViewClassName)
    if newClass == nil {
        let targetClass: AnyClass = object_getClass(target)
        newClass = objc_allocateClasspair(targetClass,noInputAccessoryViewClassName.cString(using: String.Encoding.ascii)!,0)
    }
    let originalMethod = class_getInstanceMethod(FauxBarHelper.self,#selector(getter: FauxBarHelper.inputAccessoryView))
    class_addMethod(newClass!.self,#selector(getter: FauxBarHelper.inputAccessoryView),method_getImplementation(originalMethod),method_getTypeEncoding(originalMethod))
    object_setClass(target,newClass)
} 
 HTH;)