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iOS Build a Weather App with Swift Refreshing the Data The End

Posted by Igor Alves
Igor Alves
Courses Plus Student 4,115 Points

Where should i introduce the UIAlert code?

i was trying to introduce this code in my switch statement but the self.presentViewController doesn`t work in my network operation class, only in the view controller

func creatingAnAlert(){
        let alert = UIAlertController(title: "alert", message: "network error", preferredStyle: UIAlertControllerStyle.Alert)
        alert.addAction(UIAlertAction(title: "ok", style: UIAlertActionStyle.Default, handler: nil))

    self.presentViewController(alert, animated: true, completion: nil)
    }

1 Answer

Dominic Bryan
Dominic Bryan
14,452 Points
Dominic Bryan
Dominic Bryan
14,452 Points

I am slightly unclear as to what your "network operation class" is, but I assume it is a class in another .swift file where you do some network operation which you call in your view controller.

In that case then the problem with your code is the 

self.presentViewController(alert, animated: true, completion: nil)

Using 

self.

tries to present the alert controller in the network operations class. I would suggest that in your network operations class you have a completion block, or error block so in your view controller, upon calling the network operation you can call the 

creatingAnAlert()

function in the completion block.

Igor Alves
Igor Alves
Courses Plus Student 4,115 Points

i improved my method with a completion handler and created an instance on the view controller, so i was able to use the self.presentViewController method.However when i run the app, the debug area shows this message:Warning: Attempt to present <UIAlertController: 0x7f8cba5b94d0> on <Stormy.ViewController: 0x7f8cba443900> whose view is not in the window hierarchy!

Igor Alves
Igor Alves
Courses Plus Student 4,115 Points

i was able to create an alert but i don´t know how to introduce it when the network fails, do you know how can i do that?