Problem performing segue from tableview to viewcontroller - ios

Question

I am trying to perform a segue from a UITableView with news. If you push one of the news, it performs a segue to the specific news you selected.
It is easy and I have done it a few times... but I don't know what am I doing wrong this time.
The NewsDetailViewController is like this:
class NewsDetailViewController: UIViewController {
#IBOutlet weak var newsImage: UIImageView!
#IBOutlet weak var newsTitle: UILabel!
#IBOutlet weak var newsDate: UILabel!
#IBOutlet weak var newsText: UILabel!
var newsLink: String?
override func viewDidLoad() {
super.viewDidLoad()
// Hides the navigation bar.
self.navigationController?.setNavigationBarHidden(true, animated: false)
}
#IBAction func closeNews(_ sender: UIButton) {
navigationController?.popViewController(animated: true)
}
}
And the segue in the NewsTableViewController is like this:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("you selected the row: \(indexPath.row)")
tableView.deselectRow(at: indexPath, animated: true)
self.performSegue(withIdentifier: "goToNewsDetail", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToNewsDetail" {
if let destination = segue.destination as? NewsDetailViewController {
destination.newsLink = "whateverlink"
destination.newsTitle.text = "whatevertitle"
}
}
}
And the line: destination.newsLink = "whateverlink"
Works perfectly.
But the line: destination.newsTitle.text = "whatevertitle"
Throws a
fatal error: Unexpectedly found nil while implicitly unwrapping an
Optional value.
And I have no idea of what if going on. The same problem happens when trying to initialise the rest of the labels in the destination.

Answer 1

This line is the problem
destination.newsTitle.text = "whatevertitle"
don't access outlets of the destination vc as they not yet loaded send a string and assign it to the label in the destination vc
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToNewsDetail" {
if let destination = segue.destination as? NewsDetailViewController {
destination.newsLink = "whateverlink"
destination.toSend = "whatevertitle"
}
}
}
class NewsDetailViewController: UIViewController {
#IBOutlet weak var newsTitle:UILabel!
var toSend = ""
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.newsTitle.text = toSend
}
}

Answer 2

In the prepareForSegue method, the newsTitle label is still not initialised, so it is nil.
Generally, you shouldn't set the target VC's view's properties in prepareForSegue. You should declare a newsTitleText property in NewsDetailViewController:
var newsTitleText: String!
And set this property instead:
destination.newsTitleText = "whatevertitle"
Then set the newsTitle.text in viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
// Hides the navigation bar.
self.navigationController?.setNavigationBarHidden(true, animated: false)
newsTitle.text = newsTitleText
}

Answer 3

When the prepare(for:sender:) method is called, NewsDetailViewController has not loaded the view yet so you can't set the text on a label. What you want to do is create another property on NewsDetailViewController such as var newsTitleText: String?. Then in viewDidLoad you can call newsTitle.text = newsTitleText.