如何将accessibilityIdentifier设置为UIAlertController？

问题描述

这就是我简单地创建 UIAlertController 并在屏幕上显示的方式：

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

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

    let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)
    //alert.accessibilityLabel = "my string here"      //doesnt work
    let action = UIAlertAction(title: "OK", style: .Default) { action in
        alert.dismissViewControllerAnimated(true, completion: nil)
    }

    alert.addAction(action)
    UIStoryboard.topViewController()?.presentViewController(alert, animated: true, completion: nil)
}

这就是我在 UITests 下访问它的方式：

and this is how I access it under UITests:

emailAlert = app.alerts["First Name"] //for title "First Name"

但是我想在那里设置自定义标识符并通过 firstName 访问它：

but I would like to set there custom identifier and access this by firstName like this:

emailAlert = app.alerts["firstName"]

有可能吗？

推荐答案

我想出办法的唯一方法就是使用Apple的私有API。使用此超级密钥在 UIAlertAction 对象上调用 valueForKey ：__ representer获取什么称为 _UIAlertControllerActionView 。

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"
    })

这必须在完成处理程序中完成，因为在显示视图之前 _UIAlertControllerActionView 将不存在。在我的项目的旁注中，我使用以下扩展来使事情更容易/更易读：

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
    }
}

因此上面的代码将被重写：

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()
    })

我的第一次尝试涉及尝试导航视图层次结构，但由于 UIAlertControllerActionView 不是公共API的一部分。无论如何，我可能会尝试为应用程序商店提交的构建版本中的 valueForKey（__ representer），否则Apple可能会给你打屁股。

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.

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