ios - 用另一个 UIAlertController 替换 UIAlertController

Question

我有一个 Parse Sign Up 和一个 UIAlertController，我希望 UIAlertController 显示一个指示器，但在注册出现错误时被另一个 UIAlertController 解雇。

我有几个注册失败的案例，所有这些都在添加带有指示器的 UIAlertController 之前工作。当注册成功并且正确关闭时，指示器警报 Controller 工作正常。

//create an alert controller
    let pending = UIAlertController(title: "Creating New User", message: nil, preferredStyle: .Alert)

    //create an activity indicator
    let indicator = UIActivityIndicatorView(frame: pending.view.bounds)
    indicator.autoresizingMask = .FlexibleWidth | .FlexibleHeight
    //add the activity indicator as a subview of the alert controller's view
    pending.view.addSubview(indicator)
    indicator.userInteractionEnabled = false // required otherwise if there buttons in the UIAlertController you will not be able to press them
    indicator.startAnimating()
    self.presentViewController(pending, animated: true, completion: nil)

这是注册的代码，这个有效

        if signUpError == nil {
            println("Sign Up Successful")
            // Keep track of the installs of our app
            var installation: PFInstallation =  PFInstallation.currentInstallation()
            installation.addUniqueObject("Reload", forKey: "channels")
            installation["user"] = PFUser.currentUser()
            installation.saveInBackground()


            // to stop the uialertviewcontroller once sign up successful
            pending.dismissViewControllerAnimated(true, completion: {
                self.performSegueWithIdentifier("goToAppFromSignUp", sender: self)

            })

         }

这就是我被困的地方，这只是其中一种情况，如果我能让它工作，我可以为其他人做。

        else {
            println("Error Sign Up")


            //If email has been used for another account kPFErrorUserEmailTaken
            if(signUpError!.code == 203) {

                let alertController = UIAlertController(title: "Sign Up Failed", message: "Sorry! Email has been taken! ", preferredStyle: .Alert)


                let OKAction = UIAlertAction(title: "OK", style: .Default) { (action) in
                    // ...
                }
                alertController.addAction(OKAction)



                    self.presentViewController(alertController, animated: true) {
                        // ...
                    }  
            }

我的想法是关闭 UIAlertController 并在完成 block 中显示下一个

pending.dismissViewControllerAnimated(true, completion: {
self.presentViewController(alertController, animated: true) {
                // ...
            }

        })

但应用程序在挂起的警报 Controller (带有指示器的 Controller )上卡住。 已经呈现(null)

有什么想法吗？谢谢。

Answer 1

尝试关闭挂起的警报并在没有动画的情况下显示下一个警报。

pending.dismissViewControllerAnimated(false, completion: nil)
self.presentViewController(alertController, animated: false, completion: nil)