Swift open new UIViewController - ios

Question

I'm trying to open new UIViewController when I click on an item inside UICollectionView, but using this code my app crashes and Xcode and simulator restarts so I can't even see where is the problem.
import UIKit
class ViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.register(CustomCell.self, forCellWithReuseIdentifier: "cellId")
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 5
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId", for: indexPath) as! CustomCell
cell.imageViewGame.image = UIImage(named: imageArray[indexPath.row])
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width / 2, height: view.frame.width / 2)
}
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
performSegue(withIdentifier: "postController", sender: title[indexPath.row])
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "postController" {
let postController = segue.destination as! PostController
postController.title = sender as! String
}
}
}
Does anyone know from this code why my app crashes? If it's important, I'm not using storyboard.

Answer 1

Try this:
Make you don't forgot to declare postController identifier in your segue
You just can present it modally with:
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let postController = PostController()
postController.title = title[indexPath.row]
present(postController, animated: true, completion: nil)
}