Presenting View Controller loses subviews when dismissing presented VC - ios

Question

I'm having some trouble playing around with two viewcontrollers that interact in a straightforward manner:
The homeViewController shows a to-do list, with an addTask button.
The addTask button will launch an additional viewController that acts as a "form" for the user to fill.
However, upon calling
self.dismissViewControllerAnimated(true, completion: nil);
inside the presented view controller I return to my home page, but it's blank white and it seems nothing can be seen except the highest-level view on the storyboard can be seen (i.e. the one that covers the entire screen).
All of my views, scenes, etc. were set up with autolayout in storyboard. I've looked around on Stack Overflow, which lead to me playing around with the auto-resizing subview parameter i.e.:
self.view.autoresizesSubviews = false;
to no avail. I'm either fixing the auto-resizing parameter wrong (in the wrong view of interest, or simply setting it wrong), or having some other problem.
Thanks in advance
edit:
I present the VC as follows:
func initAddNewTaskController(){
let addNewTaskVC = self.storyboard?.instantiateViewControllerWithIdentifier("AddNewTaskViewController") as! AddNewTaskViewController;
self.presentViewController(addNewTaskVC, animated: true, completion: nil);
}
edit2:
While I accept that using delegates or unwinding segue can indeed circumvent the problem I'm encountering (as campbell_souped suggests), I still don't understand what's fundamentally happening when I dismiss my view controller that causes a blank screen.
I understand that calling dismissViewControllerAnimated is passed onto the presenting view controller (in this case my homeViewController). Since I don't need to do any pre or post-dismissal configurations, the use of a delegate is (in my opinion) unnecessary here.
My current thought is that for some reason, when I invoke
dismissViewControllerAnimated(true, completion:nil);
in my addNewTaskViewController, it is actually releasing my homeViewController. I'm hoping someone can enlighten me regarding what it is exactly that I'm not understanding about how view controllers are presented/dismissed.

Answer 1

In a situation like this, I usually take one of two routes. Either set up a delegate on AddNewTaskViewController, or use an unwind segue.
With the delegate approach, set up a protocol:
protocol AddNewTaskViewControllerDelegate {
func didDismissNewTaskViewControllerWithSuccess(success: Bool)
}
Add an optional property that represents the delegate in your AddNewTaskViewController
var delegate: AddNewTaskViewControllerDelegate?
Then invoke the didDismissNewTaskViewControllerWithSuccess whenever you are about to dismiss AddNewTaskViewController:
If the record was added successfully:
self.delegate?.didDismissNewTaskViewControllerWithSuccess(true)
self.dismissViewControllerAnimated(true, completion: nil);
Or if there was a cancelation/ failure:
self.delegate?.didDismissNewTaskViewControllerWithSuccess(false)
self.dismissViewControllerAnimated(true, completion: nil);
Finally, set yourself as the delegate, modifying your previous snippet:
func initAddNewTaskController(){
let addNewTaskVC = self.storyboard?.instantiateViewControllerWithIdentifier("AddNewTaskViewController") as! AddNewTaskViewController;
self.presentViewController(addNewTaskVC, animated: true, completion: nil);
}
to this:
func initAddNewTaskController() {
guard let addNewTaskVC = self.storyboard?.instantiateViewControllerWithIdentifier("AddNewTaskViewController") as AddNewTaskViewController else { return }
addNewTaskVC.delegate = self
self.presentViewController(addNewTaskVC, animated: true, completion: nil);
}
...
}
// MARK: AddNewTaskViewControllerDelegate
extension homeViewController: AddNewTaskViewControllerDelegate {
func didDismissNewTaskViewControllerWithSuccess(success: Bool) {
if success {
self.tableView.reloadData()
}
}
}
[ Where the extension is outside of your homeViewController class ]
With the unwind segue approach, take a look at this Ray Wenderlich example:
http://www.raywenderlich.com/113394/storyboards-tutorial-in-ios-9-part-2
This approach involves Ctrl-dragging from your IBAction to the exit object above the view controller and then picking the correct action name from the popup menu