Btukfyl

I have a view controller, let's call it AddAlarmViewController.swift, which is inside a navigation controller, and in which I call

prepare(for segue: UIStoryboardSegue, sender: Any?)

This AddAlarmViewController comprises a screen in my iOS application that creates a new Alarm to add to a stack of Alarms back in a separate UIViewController based on input from some DatePickers.

Inside this prepare method, essentially before I return from this AddAlarmViewController to AlarmTableViewController, I use the following code

    // Configure the destination view controller only when the save button is pressed.

    guard let button = sender as? UIBarButtonItem, button === saveButton else {

        os_log("The cancel button was pressed, cancelling from AddAlarmViewController", log: OSLog.default, type: .debug)

        return

    }

After this, I pull the times from each datePicker into variables and use those variables to build an Alarm object.

The problem is that all of my logic for deciding whether a time is valid or not (end time is before start time, etc.) is contained in the Alarm object's init method and not in this AddAlarmViewController, so I can't seem to figure out how to change the navigation bar save button item to be disabled while invalid times are entered. Do I need to make the AddAlarmViewController a Delegate for the Alarm class or something?

Thanks

My suggestion is put the logic into

  func shouldPerformSegue(withIdentifier identifier: NSStoryboardSegue.Identifier, sender: Any?) -> Bool

That may help you solve the issue.

 extension : UIViewController{

 override  func shouldPerformSegue(withIdentifier identifier:    NSStoryboardSegue.Identifier, sender: Any?) -> Bool{

return true

}
}