Collectionview in NSObject Class doesn't work? - swift

Question

I wrote a class contain a collectionview to show in main viewcontroller,
but it was "never" shows the cell data. And the cell background color wasn't change to black..(change color is only for test, not my purpose)..
(The collectionView can be showed correctly)
Where I should to correct it?
class CellClass: NSObject,
UICollectionViewDataSource,
UICollectionViewDelegate,
UICollectionViewDelegateFlowLayout
{
let cellid = "cellid"
let cv : UICollectionView = {
let fl = UICollectionViewFlowLayout()
let v = UICollectionView(frame: .zero,
collectionViewLayout: fl)
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = UIColor.white
return v
}()
override init() {
super.init()
print("init")
cv.delegate = self
cv.dataSource = self
cv.register(Cell.self,
forCellWithReuseIdentifier: cellid)
if let window = UIApplication.shared.keyWindow {
window.addSubview(cv)
cv.frame = CGRect(x: 0,
y: window.frame.height - 300,
width: window.frame.width,
height: 300)
}
}
func collectionView(_ collectionView: UICollectionView,
numberOfItemsInSection section: Int) -> Int {
print("numberOfItemsInSection")
return 3
}
func collectionView(_ collectionView: UICollectionView,
cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
print("cell")
let vc = collectionView.dequeueReusableCell(withReuseIdentifier: cellid,
for: indexPath) as! Cell
vc.lbl.text = "test"
vc.backgroundColor = UIColor.black
return vc
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 300, height: 100)
}
}
class Cell: UICollectionViewCell {
let lbl : UILabel = {
let t = UILabel()
t.translatesAutoresizingMaskIntoConstraints = false
return t
} ()
override init(frame: CGRect) {
super.init(frame: frame)
lbl.frame = CGRect(x: 0,
y: 0,
width: 200,
height: 30)
addSubview(lbl)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}

Answer 1

I could be wrong but I have a feeling you do something like this in your viewDidLoad
let cellClass = CellClass()
As soon as the didLoad function completes its execution, cellClass no longer persists in order to be the datasource and delegate.
You can try this by adding a deinit to your CellClass
deinit {
print("Cell Class Deinit")
}
And I believe it will be called
What I suggest instead is to persist the object beyond viewDidLoad
class AVPlayerScroll: UIViewController, UIGestureRecognizerDelegate
{
var cellClass: CellClass?
override func viewDidLoad()
{
super.viewDidLoad()
cellClass = CellClass()
}
I believe this should give you the results you are looking for

Answer 2

you can try couple of things here.
You can either try to set the constraints programmatically. Something like this.
NSLayoutConstraint.activate([
lbl.leadingAnchor.constraint(equalTo: self.leadingAnchor),
lbl.topAnchor.constraint(equalTo: self.topAnchor),
lbl.widthAnchor.constraint(equalToConstant: 200),
actionSheetView.heightAnchor.constraint(equalToConstant: 30)])
You can try to assign the frame to the UILabel (lbl) subview in layoutSubviews() method.