I finally got some time to get back to this again.  The extension does a lot of 
what I need.  It works great if it is called from any UIViewController.  
However, if I call it from a function that is not in a view controller then 
Swift says notificationAlert is not defined.  There is another side effect that 
is more problematic, When the alert is displayed, I also get the message:

popViewControllerAnimated: called on <UINavigationController 0x7fc376813c00> 
while an existing transition or presentation is occurring; the navigation stack 
will not be updated.

Generally these alerts are used when a user tries to enter a view controller 
where the prerequisite data has not been provided.  I wanted the alert to 
display and then go back to the previous view controller.  I suspect that I 
will need to use completions in the notificationAlert function to do that 
rather than just following the call with the stack pop.

-- Doug

> On 9 October 2019, at 07:40, davel...@mac.com wrote:
> 
> I'm by no means an expert but if I understand what you're trying to do, I 
> think the approach I would take is to make an extension on UIViewController:
> 
> extension UIViewController {
>    func notificationAlert(_ msg1: String, _ msg2: String) {
> 
>        // create the UIAlertAlertController
>        // and then do as David Duncan said and do:
>        self.present(<alert controller>, animated: <true/false> completion: …)
>    }
> }
> 
> Now all your UIViewController subclasses can call that method (and because 
> it's a method, they have access to self which is a subclass of 
> UIViewController).
> 
> HTH,
> Dave
> 
> 
>> On Sep 30, 2019, at 11:27 PM, Doug Hardie via Cocoa-dev 
>> <cocoa-dev@lists.apple.com> wrote:
>> 
>> I tried that and swift complains that self is not defined.  This is not in a 
>> view controller but a stand alone function used in many view controllers.  
>> Generally it is used during a segue, but I added one in a view controller to 
>> a button action, not part of a segue and it dismissed the alert also.  
>> 
>> -- Doug
>> 
>>> On 30 September 2019, at 19:48, David Duncan <david.dun...@apple.com> wrote:
>>> 
>>> Instead of creating a new window and a root view controller in order to 
>>> present your alert, just use (assuming self is a UIViewController) 
>>> self.present(<alert controller>, animated: <true/false> completion: …)
>>> 
>>>> On Sep 30, 2019, at 5:48 PM, Doug Hardie <bc...@lafn.org> wrote:
>>>> 
>>>> Not sure how to do that.  It's not in any view controller as it is used in 
>>>> virtually all of the various view controllers.  That's why I wanted it as 
>>>> a function.
>>>> 
>>>> -- Doug
>>>> 
>>>>> On 30 September 2019, at 14:44, David Duncan <david.dun...@apple.com> 
>>>>> wrote:
>>>>> 
>>>>> What happens if you present it over your normal view controller hierarchy 
>>>>> instead of using another window?
>>>>> 
>>>>> Has your application adopted UIWindowScene?
>>>>> 
>>>>>> On Sep 30, 2019, at 5:36 PM, Doug Hardie via Cocoa-dev 
>>>>>> <cocoa-dev@lists.apple.com> wrote:
>>>>>> 
>>>>>> I have some code that presents an alert to the user with information 
>>>>>> they need, and an OK button to clear it.  It works fine in the previous 
>>>>>> Xcode versions.  However, after upgrading to 11, it now displays the 
>>>>>> alert and then immediately clears it.  This happens both in the 
>>>>>> simulator and on a real device.  I have played around with the code and 
>>>>>> can't figure out how to make it leave the alert on the screen.  This is 
>>>>>> in Swift.  It is a function that is called from numerous places in the 
>>>>>> app.
>>>>>> 
>>>>>> func NotificationAlert (_ msg1: String, _ msg2: String) {
>>>>>> let ErrorAlert = UIAlertController(title: msg1, message: msg2, 
>>>>>> preferredStyle: .alert)
>>>>>> let dismiss = UIAlertAction(title: "Ok", style: .default, handler: nil)
>>>>>> ErrorAlert.addAction(dismiss)
>>>>>> ErrorAlert.presentInOwnWindow(animated: true, completion: nil)
>>>>>> }
>>>>>> 
>>>>>> extension UIAlertController {
>>>>>> func presentInOwnWindow(animated: Bool, completion: (() -> Void)?) {
>>>>>>   let alertWindow = UIWindow(frame: UIScreen.main.bounds)
>>>>>>   alertWindow.rootViewController = UIViewController()
>>>>>>   alertWindow.windowLevel = UIWindow.Level.alert + 1;
>>>>>>   alertWindow.makeKeyAndVisible()
>>>>>>   alertWindow.rootViewController?.present(self, animated: animated, 
>>>>>> completion: completion)
>>>>>> }
>>>>>> }
>>>>>> 
>>>>>> 
>>>>>> -- Doug
>>>>>> 
>>>>>> _______________________________________________
>>>>>> 
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>>>>> 
>>>> 
>>> 
>> 
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>> 
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