I am used to customize UIAlertViews through the [alert setValue:someView forKey:@\"accessoryView\"] method. This creates customizable content for U
UIAlertViews
alert setValue:someView forKey:@\"accessoryView\"]
I think you can easily customize the UIView adding the controls needed and present it modally, unless you have any other specific reason to use only UIAlertController.
https://www.cocoacontrols.com/search?q=UIAlertview