Best way to communicate between UITableViewCell and UIViewController

Question

The code below works but there is probably a better way. My goal is to call a UIViewController function from the UITableCell when aborting from edit mode.

I am doing this by setting an instantiated UIViewController reference to every UITableViewCell and then calling a function, CancelDelete(), on the UITableViewCell state change.

The code seems inefficient since for every MyCell I first instantiate a placeholder MyViewContoller as the public variable and then replace it with reference to the UIViewController when the UITableView initializes.

Is there a better way to do this?

class MyCell : UITableViewCell
{
    var previousState : UITableViewCellStateMask = UITableViewCellStateMask.allZeros

    // This holds a reference to the parent view controller
    // Seems wasteful to instantiate since it gets replaced
    var controller:MyViewController = MyViewController()

    // This is called when the user aborts edit mode
    override func willTransitionToState(state: UITableViewCellStateMask) {

        if state & UITableViewCellStateMask.ShowingEditControlMask != nil {
            if previousState & UITableViewCellStateMask.ShowingDeleteConfirmationMask != nil { 

            // send notification to controller 
            controller.CancelDelete(self)
        }
    }

    previousState = state
    }    
}


class MyViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        // Give cell access to this controller                        
        var cell:MyCell = tableView.dequeueReusableCellWithIdentifier("cell") as MyCell
        cell.controller = self
        cell.tag = indexPath.row
    }

    // This is called from the table cell
    func CancelDelete(cell:MyCell) {
            editButtons[cell.tag].hidden = false
    }

}

Answer 1

Change the type of controller to MyViewController! instead of MyViewController. Also, set it to a default value of nil.

The declaration of controller should look like this:

var controller: MyViewController! = nil

If you have any questions about types that end with an exclamation mark (!), look at: https://developer.apple.com/library/mac/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html (in the section named Optionals).