Navigate between view controllers without storyboards/xibs - ios

Question

I'm developing an application without storyboards/xibs, which is proving to be a challenge. I have a UICollectionView (of ads) where users can tap on a cell to navigate to a new view controller to show details for that ad. Below is a gif of the error I'm having.
As you can see, the UICollectionView kind of sticks around after I tap the cell. I have a adDetailsViewController property in my AdsViewController subclass, and when I tap the cell this code executes:
adDetailsViewController.adTitle = adTitles[indexPath.row]
navigationController?.pushViewController(adDetailsViewController, animated: true)
Below are the life cycle methods (currently just viewDidLoad) of adDetailsViewController:
class AdDetailsViewController: UIViewController {
var adTitle: String?
override func viewDidLoad() {
super.viewDidLoad()
let label = UILabel(frame: view.bounds)
label.textAlignment = .center
label.center = view.center
label.text = adTitle
view.addSubview(label)
}
}
For completeness, here's the rest of AdsViewController:
class AdsViewController: UIViewController {
lazy var collectionView: AdsCollectionView = {
let collectionView = AdsCollectionView(frame: view.frame, collectionViewLayout: TiledFlowLayout())
collectionView.delegate = self
collectionView.dataSource = self
collectionView.register(AdCollectionViewCell.self, forCellWithReuseIdentifier: "AdCell")
view.addSubview(collectionView)
return collectionView
}()
let adDetailsViewController = AdDetailsViewController()
let adTitles = ["1", "2", "3", "4", "5", "6"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
collectionView.translatesAutoresizingMaskIntoConstraints = false
collectionView.topAnchor.constraint(equalTo: view.topAnchor, constant: 8).isActive = true
collectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true
collectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
collectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = true
view.backgroundColor = .white
}
}
extension AdsViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return adTitles.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "AdCell", for: indexPath) as! AdCollectionViewCell
cell.textLabel.text = adTitles[indexPath.row]
return cell
}
}
extension AdsViewController: UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
adDetailsViewController.adTitle = adTitles[indexPath.row]
navigationController?.pushViewController(adDetailsViewController, animated: true)
}
}
extension AdsViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: (self.view.frame.size.width / 2) - 10, height: self.view.frame.size.height / 4)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
}
}

Answer 1

Ok, I fixed it. It seems that if I set the backgroundColor of AdDetailsViewController to UIColor.white, then it transitions as expected.

Answer 2

You have to share more of your code. Are there any special settings f.e.? Like a transparent background? Anything you do in viewDidLoad? Did you overwrite viewWillAppear, viewDidAppear, etc. and did not call the subclass functions (like super.viewWillAppear(animated))? That's a very common mistake...