How to subclass an UIViewController with UITableViewDelegate in many subclasses

Question

I would like to have a reusable view controller called MainViewController with a UITableView inside.

class MainViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

@IBOutlet var tableView : UITableView!

    override func viewDidLoad() {

        super.viewDidLoad()

        self.tableView.dataSource = self
        self.tableView.delegate = self
        self.tableView.scrollsToTop = true

        self.tableView.estimatedRowHeight = 124.0
        self.tableView.rowHeight = UITableViewAutomaticDimension
}

I need to have many subclasses of my MainViewController, to can custom them depending of my needs. IntroViewController is one of them.

class IntroViewController: MainViewController {

}

To open the IntroViewController, here my segue:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    if segue.identifier == "intro" {

        let destination =  segue.destination as! UINavigationController
        let ivc = destination.topViewController as! IntroViewController
    }

}

I got this crash:

fatal error: unexpectedly found nil while unwrapping an Optional value

for the line

self.tableView.dataSource = self

I checked, my outlets are linked correctly. Datasource too.

I could be used a custom segue instead the navigation controller — cmii, Apr 11 '17 at 15:28

score 0 · Accepted Answer · edited May 23 '17 at 11:54

What you're trying to do doesn't really work that way. The @IBOutlets are all connected through the Storyboard - but they don't "flow through" in the pattern you're hoping to use.

You can do it - in a way. Take a look a the discussion and answers in this SO post: How to subclass custom UIViewController in Swift?

Alternatively, if you're goal is to use a "common" table view controller - but allow customization - you can create separate UITableViewDelegate and UITableViewDataSource files, plus separate visually designed cells, and then assign them via code as desired.

How to subclass an UIViewController with UITableViewDelegate in many subclasses

1 Answers1