How to reference UITableViewController from a UITableViewCell class?

Question

I have the following:

1. UITableViewController
2. UITableView
3. Custom UITableViewCell subclass

I used a .xib file for the cell, which is a CustomCell subclass. This custom cell handles IBActions for some touch events on the cell's buttons.

I'd like to reference the ViewController and some of its variables from the cell.

How am I supposed to access the UITableViewController from the UITableViewCell class?

Answer 1

I wouldn't create this kind of dependency between the cell and the view controller - that makes the architecture more intricate and the cell not reusable.

I suggest you to use the delegation pattern, which may sound a little complicated - although you're already using ( UITableViewDelegate is a typical example):

• create a protocol MyCellProtocol with one method didTapCell , accepting a UITableViewCell and/or some custom data you want to pass to the view controller
• create a public delegate property in your custom cell: weak var cellDelegate: MyCellProtocol?
• in the didTapXXX handler or didSelectRowAtIndexPath of your cell, call self.cellDelegate?.didTapCell() , passing the expected parameters
• in your view controller, implement the MyCellProtocol
• in cellForRowAtIndexPath of your view controller, when creating/dequeuing the cell, set its cellDelegate property to self

At this point, when a tap is done in your cell, the didTapCell method of the view controller is called, and from there you can do whatever you need to achieve.

The key point is: rather than making the cell handle the cell tap/selection, notify the view controller and let it do the job.

Answer 2

extension UIView {
    var parentViewController: UIViewController? {
        var parentResponder: UIResponder? = self
        while parentResponder != nil {
            parentResponder = parentResponder!.next
            if let viewController = parentResponder as? UIViewController {
                return viewController
            }
        }
        return nil
    }
}

Inside your cell

if let myViewController = parentViewController as? MyViewController {
    print(myViewController.title)
}

Answer 3

I don't think you should do that and probably you're doing something wrong but if you really-really need it then just have a property in your CustomCell class.

weak var viewController : UIViewController

then when you create the cell in cellForRowAtIndexPath set the property

cell.viewController = self

after that you can easily access the view controller from within the cell code:

self.viewController.doSomething()

But again, in my opinion, you should redesign your code. The cell should not care about the controller. It should care only about displaying itself and nothing else

Answer 4

add Extension

 extension UITableViewCell {

        var viewControllerForTableView : UIViewController?{
            return ((self.superview as? UITableView)?.delegate as? UIViewController)
        }

    }

now downCast as below

   if let viewController = self.viewControllerForTableView as? AnyController{

       print(viewController.variable)

   } 

.

Answer 5

Best way is to implement Delegation. Your delegate will inform the view controller about the button click. And, In turn your view controller (who is conforming the protocol for above delegate) will handle the task that you want to perform on click event. (Delegation pattern tutorials are available online. you can go through them if you want to know how to do delegation).

Answer 6

Read the other comments about really wanting to use an alternate approach before trying this, but using this extension will allow you to get to the dataSource and delegate both of which should be the UITableViewController

extension UITableViewCell {
    var tableView:UITableView? {
        get {
            for var view = self.superview ; view != nil ; view = view!.superview {
                if view! is UITableView {
                    return (view! as UITableView)
                }
            }
            return nil
        }
    }

    var tableViewDataSource:UITableViewDataSource? {
        get {
            return self.tableView?.dataSource
        }
    }

    var tableViewDelegate:UITableViewDelegate? {
        get {
            return self.tableView?.delegate
        }
    }
}