I have multiple ViewController with a CollectionView each. In every CollectionView I want to do something after a Cell is selected. In one ViewController it's not working, but in every other it works.
I checked the delegates, datasource and registration of Cells multiple times but it's like in the other ViewControllers too so I cant see, why it's not working. Also I dont have any Buttons in the Cell, I saw before that you can't use "didSelectItemAt" when you have Buttons in Cell. Additionally I commented out the part where I add the Subviews and constraints, but it still didn't get called.
ViewController which is not working:
class HomeController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout, HomeControllerDelegate {
lazy var eventCollectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.minimumLineSpacing = 25
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.dataSource = self
cv.delegate = self
return cv
}()
let eventCellId = "EventCellId"
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(eventCollectionView)
eventCollectionView.anchorWithConstantsToTop(view.topAnchor, left: view.leftAnchor, bottom: view.bottomAnchor, right: view.rightAnchor, topConstant: 94, leftConstant: 25, bottomConstant: 25, rightConstant: 25)
eventCollectionView.register(EventCell.self, forCellWithReuseIdentifier: eventCellId)
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 24
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = eventCollectionView.dequeueReusableCell(withReuseIdentifier: eventCellId, for: indexPath) as! EventCell
cell.backgroundColor = UIColor(displayP3Red: 245/255, green: 245/255, blue: 245/255, alpha: 1)
cell.layer.borderColor = UIColor(displayP3Red: 233/255, green: 233/255, blue: 233/255, alpha: 1).cgColor
cell.layer.borderWidth = 1
cell.layer.cornerRadius = 2
cell.homeControllerDelegate = self
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
if view.frame.width < 415.0 {
return CGSize(width: view.frame.width - 50, height: view.frame.width - 60)
}
else if view.frame.width < 828.0 {
return CGSize(width: (view.frame.width / 2) - 50, height: (view.frame.width / 2) - 60)
}
else {
return CGSize(width: (view.frame.width / 3) - 50, height: (view.frame.width / 3) - 60)
}
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print("Selected Event Cell")
}
}
ViewController which is working:
class FavoritesController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout, FavoritesControllerDelegate {
lazy var favoritesCollectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.minimumLineSpacing = 5
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.backgroundColor = UIColor(displayP3Red: 235/255, green: 235/255, blue: 235/255, alpha: 1)
cv.dataSource = self
cv.delegate = self
return cv
}()
let favoritesCellId = "FavoritesCellId"
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(favoritesCollectionView)
favoritesCollectionView.anchorToTop(view.topAnchor, left: view.leftAnchor, bottom: view.bottomAnchor, right: view.rightAnchor)
registerCells()
sideNavigationController = ""
}
fileprivate func registerCells() {
favoritesCollectionView.register(FavoritesCell.self, forCellWithReuseIdentifier: favoritesCellId)
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 6
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = favoritesCollectionView.dequeueReusableCell(withReuseIdentifier: favoritesCellId, for: indexPath) as! FavoritesCell
cell.backgroundColor = .white
cell.layer.cornerRadius = 2
cell.favoritesControllerDelegate = self
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: 125)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print("Selected Favorites Cell")
}
}
Constraints are added with this extension of UIView:
extension UIView {
func anchorToTop(_ top: NSLayoutYAxisAnchor? = nil, left: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, right: NSLayoutXAxisAnchor? = nil) {
anchorWithConstantsToTop(top, left: left, bottom: bottom, right: right, topConstant: 0, leftConstant: 0, bottomConstant: 0, rightConstant: 0)
}
func anchorWithConstantsToTop(_ top: NSLayoutYAxisAnchor? = nil, left: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, right: NSLayoutXAxisAnchor? = nil, topConstant: CGFloat = 0, leftConstant: CGFloat = 0, bottomConstant: CGFloat = 0, rightConstant: CGFloat = 0) {
_ = anchor(top, left: left, bottom: bottom, right: right, topConstant: topConstant, leftConstant: leftConstant, bottomConstant: bottomConstant, rightConstant: rightConstant)
}
func anchor(_ top: NSLayoutYAxisAnchor? = nil, left: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, right: NSLayoutXAxisAnchor? = nil, topConstant: CGFloat = 0, leftConstant: CGFloat = 0, bottomConstant: CGFloat = 0, rightConstant: CGFloat = 0, widthConstant: CGFloat = 0, heightConstant: CGFloat = 0) -> [NSLayoutConstraint] {
translatesAutoresizingMaskIntoConstraints = false
var anchors = [NSLayoutConstraint]()
if let top = top {
anchors.append(topAnchor.constraint(equalTo: top, constant: topConstant))
}
if let left = left {
anchors.append(leftAnchor.constraint(equalTo: left, constant: leftConstant))
}
if let bottom = bottom {
anchors.append(bottomAnchor.constraint(equalTo: bottom, constant: -bottomConstant))
}
if let right = right {
anchors.append(rightAnchor.constraint(equalTo: right, constant: -rightConstant))
}
if widthConstant > 0 {
anchors.append(widthAnchor.constraint(equalToConstant: widthConstant))
}
if heightConstant > 0 {
anchors.append(heightAnchor.constraint(equalToConstant: heightConstant))
}
anchors.forEach({$0.isActive = true})
return anchors
}
func addConstraintsWithFormat(format: String, views: UIView...) {
var viewsDictionary = [String: UIView]()
for (index, view) in views.enumerated() {
let key = "v\(index)"
view.translatesAutoresizingMaskIntoConstraints = false
viewsDictionary[key] = view
}
addConstraints(NSLayoutConstraint.constraints(withVisualFormat: format, options: NSLayoutFormatOptions(), metrics: nil, views: viewsDictionary))
}
}
I found the problem within an extension of UIViewController, which was using UITapGestureRecognizer. Because of this, the tap on the cell was not handled by the collectionView delegate but by the extension.