UIMenuItem #selector method crash in wkwebview

问题

UIMenuItem selector method crashes in iOS 11 beta SDK.

-[WKContentView highlightText]: unrecognized selector sent to instance 0x7f85df8f3200

Method Definition:

func highlightText() 
{
  //
}

I try to add UIMenuItem in WKWebView,

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

回答1:

I was also getting this error when I was overriding canPerformAction and checking for my custom selector. In my case I wanted to remove all menu items except for my custom one and the following made this work for me.

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
    }
}

回答2:

OK, we finally made it work for Swift 4:

In your WKWebView subclass, add the following property and method:

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


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

Then, add an extension to UIView (I put it in the same file as my WKWebView subclass, you can make it fileprivate if you'd like)

// 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
    }
}

Now the UIMenuItem works as expected:

But honestly, this really feels like a hack, and I would love Apple to fix this issue :-/

Thanks for Stephan Heilner for his answer: https://stackoverflow.com/a/42985441/4670400

来源：https://stackoverflow.com/questions/45538886/uimenuitem-selector-method-crash-in-wkwebview

标签

crash

selector

wkwebview

uimenuitem