ios - 带有 Activity Loader 的 Alert ViewController 收到警告而不是关闭 Swift

Question

在我的场景中，我试图在 AlertViewController 中创建 Loader。在这里，我得到低于警告并且在两次试验后不允许解雇。我在公共(public)类中使用以下函数并在多个 viewController 中重用。

我的代码

    // MARK: Common AlertView
        extension UIViewController {

            func loadinHubShow() {

                    let alert = UIAlertController(title: nil, message: "Please wait...", preferredStyle: .alert)
                    let loadingIndicator = UIActivityIndicatorView(frame: CGRect(x: 10, y: 5, width: 50, height: 50))
                    loadingIndicator.hidesWhenStopped = true
                    loadingIndicator.style = UIActivityIndicatorView.Style.gray
                    loadingIndicator.startAnimating();
                    alert.view.addSubview(loadingIndicator)
                    present(alert, animated: true, completion: nil)
                }

                func loadinHubDismiss() {
                    dismiss(animated: false, completion: nil)
                }
        }

其他 View Controller

    func dataJson() {

 // Start Loading
    self.loadinHubShow()

// after process done
 DispatchQueue.main.async {
         self.loadinHubDismiss()
    }
}

我的警告

Warning: Attempt to dismiss from view controller while a presentation or dismiss is in progress!

Answer 1

如我所见，您将此函数用作 UIViewController 扩展。

获得结果的一种方法是获取对您正在使用的警报的引用。

NOTE: If you use dismiss function as you did, you're trying to dismiss the viewController, not the alert, that's why you're getting that warning.

尝试以这种方式更改您的扩展功能:

1) loadinHubShow 将返回一个 reference 到 alert

      func loadinHubShow() -> UIAlertController {

            let alert = UIAlertController(title: nil, message: "Please wait...", preferredStyle: .alert)
            let loadingIndicator = UIActivityIndicatorView(frame: CGRect(x: 10, y: 5, width: 50, height: 50))
            loadingIndicator.hidesWhenStopped = true
            loadingIndicator.style = UIActivityIndicatorView.Style.gray
            loadingIndicator.startAnimating();
            alert.view.addSubview(loadingIndicator)

            return alert
            //You don't have to present the alert here
            //present(alert, animated: true, completion: nil)
        }

2) loadinHubDismiss 将删除该警报:

         func loadinHubDismiss(alert: UIAlertController) {
            alert.dismiss(animated: false, completion: nil)
        }

为了使用这些功能，我们假设您有 ViewController:

            class ViewController: UIViewController{

              var myAlert: UIAlertController = UIAlertController()

               override func viewDidLoad(...){
                  myAlert = self.loadinHubShow()
                  //now you can present or dismiss the alert wherever you want
                  //for example:
                  self.present(myAlert,animated: false, completion: nil)

                  //when you want dismiss the alert, just call:
                  self. loadinHubDismiss(alert: myAlert)
               }



            }

编辑

要按照建议关闭警报，请尝试:

   DispatchQueue.main.async{
        loadinHubDismiss(alert: myAlert)
   }