Push viewController from CollectionView cell programmatically not working - swift

Question

I am a new iOS programming. Now i am creating a sample app by not using storyboard which i implemented UICollectionView for the main class which scroll direction is vertical. A particular cell i added another UICollectionView for horizontal direction. The problem is that cell which horizontal scroll direction is not pushing to another view controller which i click on it.

Here is rootViewController that i setup in AppDelegate

window = UIWindow(frame: UIScreen.main.bounds)
window?.makeKeyAndVisible()
let navigation = UINavigationController(rootViewController: CategoryController())
window?.rootViewController = navigation

Here is CategoryController which i implement tableView

tableView.register(TableCell.self, forCellReuseIdentifier: cellId)

override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 5
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath)

    return cell
}

override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 120
}

For tableView when i click on particular cell is working fine when i want to navigate to a particular controller

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    print(indexPath.item)
    let view = DetailEachCellController()
    navigationController?.pushViewController(view, animated: true)
}

The problem is that in DetailEachCellController i use UICollectionView for list down some data, and when i click on particular cell is not navigate to new controller

Here DetailEachCellController as UIViewController

var collectionDetailView: UICollectionView!
collectionDetailView.register(DetailContactCell.self, forCellWithReuseIdentifier: cellIdContact)
collectionDetailView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellIdContent)

func setupCollectionView() {
    collectionDetailView.topAnchor.constraint(equalTo: detailContent.topAnchor).isActive = true
    collectionDetailView.widthAnchor.constraint(equalTo: detailContent.widthAnchor).isActive = true
    collectionDetailView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    collectionDetailView.backgroundColor = .white 
}

func callAction() {
    print("pushing view")
    let view = UIViewController()
    self.navigationController?.pushViewController(view, animated: true)
}

Here the delegate for UICollectionViewFlowLayout

extension DetailEachCellController : UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if indexPath.item == 0 {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContact, for: indexPath)

            return cell
        }
        else {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContent, for: indexPath)
            cell.backgroundColor = .blue
            return cell
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        if indexPath.item == 1 {
          return CGSize(width: view.frame.width, height: 250)
        }
        return CGSize(width: view.frame.width, height: 120)
    }
}

Here is DetailContactCell which i added some buttons for user click and more to next view, but it is not moving but the function is called.

class DetailContactCell: UICollectionViewCell {

var eachCellController: DetailEachCellController?

lazy var callButton: UIButton = {

    let button = UIButton()
    button.translatesAutoresizingMaskIntoConstraints = false
    button.layer.shadowOpacity = 0.25
    button.backgroundColor = .white
    button.setTitle("CALL", for: .normal)
    button.layer.cornerRadius = 10
    button.layer.shadowOffset = CGSize(width: 0, height: 10)
    button.layer.shadowRadius = 10
    return button
}()
lazy var bookButton: UIButton = {

    let button = UIButton()
    button.translatesAutoresizingMaskIntoConstraints = false
    button.layer.shadowOpacity = 0.25
    button.backgroundColor = .white
    button.layer.cornerRadius = 10
    button.layer.shadowOffset = CGSize(width: 0, height: 10)
    button.layer.shadowRadius = 10
    return button
}()
override init(frame: CGRect) {
    super.init(frame: frame)
    addSubview(callButton)
    addSubview(bookButton)
    callButton.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
    callButton.leftAnchor.constraint(equalTo: self.leftAnchor, constant: 15).isActive = true
    callButton.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1/2.5).isActive = true
    callButton.heightAnchor.constraint(equalToConstant: 60).isActive = true

    bookButton.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
    bookButton.rightAnchor.constraint(equalTo: self.rightAnchor, constant: -15).isActive = true
    bookButton.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1/2.5).isActive = true
    bookButton.heightAnchor.constraint(equalToConstant: 60).isActive = true

    self.actionButton()
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

func actionButton() {
    callButton.addTarget(self, action: #selector(callBtn), for: .touchUpInside)
}

@objc func callBtn() {
    print("calling")
    eachCellController = DetailEachCellController()
    eachCellController?.callAction()
}

}

Answer 1

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if indexPath.item == 0 {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContact, for: indexPath) as! DetailContactCell
        // Here is line add to `UICollectionViewFlowLayout`
        cell.eachCellController = self

        return cell
    }else {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContent, for: indexPath)
        cell.backgroundColor = .blue
        return cell
    }

}