Question

UIMenuItem选择器方法在iOS 11 beta SDK中崩溃。

- [WKContentView highlightText]：无法识别的选择器发送到实例0x7f85df8f3200

方法定义：

func highlightText() 
{
  //
}

我尝试在WKWebView中添加UIMenuItem，

let menuItemHighlight = UIMenuItem.init(title: "Highlight", action: #selector(ContentWebkitView.highlightText))
UIMenuController.shared.menuItems = [menuItemHighlight]

Answer 1

当我覆盖canPerformAction并检查我的自定义选择器时，我也收到此错误。在我的情况下，我想删除除我的自定义菜单项以外的所有菜单项，以下内容使我的工作正常。

class ViewController: UIViewController {

    @IBOutlet weak var webView: MyWebView!

    override func viewDidLoad() {
        super.viewDidLoad()

        loadWebView()
        setupCustomMenu()
    }

    func loadWebView() {
        let url = URL(string: "http://www.google.com")
        let request = URLRequest(url: url!)
        webView.load(request)
    }

    func setupCustomMenu() {
        let customMenuItem = UIMenuItem(title: "Foo", action:
            #selector(ViewController.customMenuTapped))
        UIMenuController.shared.menuItems = [customMenuItem]
        UIMenuController.shared.update()
    }

    @objc func customMenuTapped() {
        let yay = ""
        let alertView = UIAlertController(title: "Yay!!", message: yay, preferredStyle: .alert)
        alertView.addAction(UIAlertAction(title: "cool", style: .default, handler: nil))
        present(alertView, animated: true, completion: nil)
    }
}

class MyWebView: WKWebView {
    // turn off all other menu items
    override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
        return false
    }
}

Answer 2

好的，我们终于让它适用于Swift 4：

在WKWebView子类中，添加以下属性和方法：

// MARK: - Swizzling to avoid responder chain crash    
var wkContentView: UIView? {
    return self.subviewWithClassName("WKContentView")
}


private func swizzleResponderChainAction() {
    wkContentView?.swizzlePerformAction()
}

然后，为UIView添加一个扩展名（我把它放在与我的WKWebView子类相同的文件中，如果你愿意，可以使它成为fileprivate）

// MARK: - Extension used for the swizzling part linked to wkContentView 
extension UIView {

    /// Find a subview corresponding to the className parameter, recursively.
    func subviewWithClassName(_ className: String) -> UIView? {

        if NSStringFromClass(type(of: self)) == className {
            return self
        } else {
            for subview in subviews {
                return subview.subviewWithClassName(className)
            }
        }
        return nil
    }

    func swizzlePerformAction() {
        swizzleMethod(#selector(canPerformAction), withSelector: #selector(swizzledCanPerformAction))
    }

    private func swizzleMethod(_ currentSelector: Selector, withSelector newSelector: Selector) {
        if let currentMethod = self.instanceMethod(for: currentSelector),
            let newMethod = self.instanceMethod(for:newSelector) {
            let newImplementation = method_getImplementation(newMethod)
            method_setImplementation(currentMethod, newImplementation)
        } else {
            print("Could not find originalSelector")
        }
    }

    private func instanceMethod(for selector: Selector) -> Method? {
        let classType = type(of: self)
        return class_getInstanceMethod(classType, selector)
    }

    @objc private func swizzledCanPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
        return false
    }
}

现在UIMenuItem按预期工作：

但说实话，这真的感觉像是黑客，我希望Apple能解决这个问题： - /

感谢Stephan Heilner的回答：https://stackoverflow.com/a/42985441/4670400

UIMenuItem #selector方法在wkwebview中崩溃

2 个答案: