How can I set accessibilityIdentifier to UIAlertController?

Question

This is how I simply create UIAlertController and present it on the screen:

private class func showAlertWithTitle(title: String, message: String) {
         


        

Answer 1

The only way I figured out to do this was to use Apple's private APIs. You call valueForKey on the UIAlertAction object with this super secret key: "__representer" to get whats called a _UIAlertControllerActionView.

    let alertView = UIAlertController(title: "This is Alert!", message: "This is a message!", preferredStyle: .Alert)
    let okAction = UIAlertAction(title: "OK", style: .Default, handler: nil)

    alertView.addAction(okAction)

    self.presentViewController(alertView, animated: true, completion: {
        let alertButton = action.valueForKey("__representer")
        let view = alertButton as? UIView
        view?.accessibilityIdentifier = "okAction_AID"
    })

This has to be done in the completion handler because that that _UIAlertControllerActionView won't exist until the view is presented. On a side note in my project I used these following extensions to make things easier / more readable:

extension UIAlertController {
    func applyAccessibilityIdentifiers()
    {
        for action in actions
        {
            let label = action.valueForKey("__representer")
            let view = label as? UIView
            view?.accessibilityIdentifier = action.getAcAccessibilityIdentifier()
        }

    }

}

extension UIAlertAction
{
    private struct AssociatedKeys {
        static var AccessabilityIdentifier = "nsh_AccesabilityIdentifier"
    }

    func setAccessibilityIdentifier(accessabilityIdentifier: String)
    {
        objc_setAssociatedObject(self, &AssociatedKeys.AccessabilityIdentifier, accessabilityIdentifier, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
    }

    func getAcAccessibilityIdentifier() -> String?
    {
        return objc_getAssociatedObject(self, &AssociatedKeys.AccessabilityIdentifier) as? String
    }
}

So the above code would be rewritten:

    let alertView = UIAlertController(title: NSLocalizedString("NMN_LOGINPAGECONTROLLER_ERROR_TITLE", comment: ""), message: message as String, preferredStyle:.Alert)
    let okAction = UIAlertAction(title: NSLocalizedString("NMN_OK", comment: ""), style: .Default, handler: nil)
    okAction.setAccessibilityIdentifier(InvalidLoginAlertView_AID)


    alertView.addAction(okAction)


    self.presentViewController(alertView, animated: true, completion: {
        alertView.applyAccessibilityIdentifiers()
    })

My first attempt involved trying to navigate the view hierarchy but that became difficult since UIAlertControllerActionView was not a part of the public API. Anyway I'd probably would try to ifdef out the valueForKey("__representer") for builds submitted for the app store or Apple might give you a spanking.