DispatchQueue:在非主线程上无法使用asCopy = NO调用

Question

我UIAlertController将主线程呈现为:

class HelperMethodClass: NSObject {

    class func showAlertMessage(message:String, viewController: UIViewController) {
        let alertMessage = UIAlertController(title: "", message: message, preferredStyle: .alert)

        let cancelAction = UIAlertAction(title: "Ok", style: .cancel)

        alertMessage.addAction(cancelAction)

        DispatchQueue.main.async {
            viewController.present(alertMessage, animated: true, completion: nil)
        }
    }
}

我从任何方面调用方法UIViewController:

HelperMethodClass.showAlertMessage(message: "Any Message", viewController: self)

我正确地得到了输出.

但在控制台中,我收到以下消息:

[Assert]在非主线程上无法使用asCopy = NO调用.

我在这里做错了什么,或者我可以忽略这个消息？

编辑

感谢@NicolasMiari:

添加以下代码不会显示任何消息:

DispatchQueue.main.async {
    HelperMethodClass.showAlertMessage(message: "Any Message", viewController: self)
}

之前它在控制台中显示消息的原因是什么？

Answer 1

您应该从showAlertMessage主队列中调用所有代码:

class func showAlertMessage(message:String, viewController: UIViewController) {
    DispatchQueue.main.async {
        let alertMessage = UIAlertController(title: "", message: message, preferredStyle: .alert)

        let cancelAction = UIAlertAction(title: "Ok", style: .cancel)

        alertMessage.addAction(cancelAction)

        viewController.present(alertMessage, animated: true, completion: nil)
    }
}