我有多个ViewController，每个ViewController都有一个CollectionView。我想在每个CollectionView中选择一个单元格后做一些事情。在一个ViewController中，它不起作用，但在其他所有视图中，它都起作用。
我多次检查了Cells的委托，数据源和注册，但是这也和其他ViewControllers一样，所以我看不到为什么它不起作用。另外，我在单元格中没有任何按钮，我之前看到，当单元格中有按钮时，您将无法使用“ didSelectItemAt”。另外，我注释掉了添加子视图和约束的部分，但仍然没有被调用。
不起作用的ViewController：
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")
}
}
正在运行的ViewController：
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")
}
}
使用此UIView扩展添加了约束：
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))
}
}