UINavigationController没有后退按钮

Question

Very simple scenario with lots of posts on this, but I'm still stuck. I have a UITableView that is embedded in a UINavigationController There is a final UIViewController that is supposed to be presented when the UITableViewCell is selected. When I wire all of this up, nothing happens on the row selection.

I can get the detail view to be presented by usind didSelectRowAtIndexPath and referencing the segue by its id. However, there is no back button when I do this.

class MainViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet weak var tableview: UITableView!
    var configJson: JSON = []
    var config: [Tab] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        parseConfig()
    }

    func parseConfig() {
        let configParser = ConfigParser(configJson: configJson)
        config = configParser.parse()
    }

    public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.config.count
    }

    public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let tab = self.config[indexPath.row]

        let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "cell")

        cell.textLabel?.text = tab.title

        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        performSegue(withIdentifier: "contentSegue", sender: self)
    }

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

        if (segue.identifier == "contentSegue") {
            let nextVC = segue.destination as? ContentViewController
            let indexPath = self.tableview.indexPathForSelectedRow
            let tab = self.config[(indexPath?.row)!]
            nextVC?.tab = tab
        }
    }
}

A couple of other notes: 1. My cell identifer is set to 'cell' in the IB
2. My segue is set to 'show' with a identifier of 'contentSegue' in the IB
3. The segue is from the prototype cell to the Content View Controller.

I'm at a total loss. Can anyone help? Thanks.

Answer 1

Are you sure you've set this up as a selection segue, and not an accessory action? You can check this by ctrl clicking on the cell in the storyboard - make sure your triggered segue is selection.

Also…

As you've added the segue in your storyboard, there's no need to fire it in didSelectRowAt - so you can remove that func.

And, to remove your reliance on a string comparison (and remove a force unwrapped optional), try this…

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let nextVC = segue.destination as? ContentViewController, 
       let cell = sender? as UITableViewCell,
       let indexPath = tableview.indexPath(for: cell) {

        let tab = self.config[indexPath.row]
        nextVC.tab = tab
    }
}