Swift 修改WKWebView的keyboardAppearance

最近做个需求，期望修改wkwebview键盘弹起时的键盘颜色为黑色，但是看文档keyboardAppearance只在UITextView相关组件上。

google查到的ionic-plugin-keyboard有一个解决方案，不过是OC的，现翻译为swift的实现.

extension WKWebView {
  @objc var darkKeyboardAppearanceTemplateMethod: UIKeyboardAppearance {
    return .dark
  }
  
  @objc var lightKeyboardAppearanceTemplateMethod: UIKeyboardAppearance {
    return .light
  }

  func setStyleDark (isDark: Bool = true) {
    var candidateView: UIView? = nil
    for view in self.scrollView.subviews {
      if String(describing: type(of: view)).hasPrefix("WKContent") {
        candidateView = view
      }
    }
    guard let targetView = candidateView else {
      return
    }
    
    var method: Method!
    if isDark {
      method = class_getInstanceMethod(EditorWebView.self, #selector(getter: darkKeyboardAppearanceTemplateMethod))
    } else {
      method = class_getInstanceMethod(EditorWebView.self, #selector(getter: lightKeyboardAppearanceTemplateMethod))
    }
    let imp = method_getImplementation(method!)
    let typeEncoding = method_getTypeEncoding(method!)
    class_replaceMethod(targetView.superclass, #selector(getter: UITextInputTraits.keyboardAppearance), imp, typeEncoding)
  }
}

初始化webview后调用webview.setStyleDark即可

ps: 感觉苹果对webview都是区别对待啊