CollectionView inside another CollectionViewCell - ios

Question

I am trying to create collectionView inside another collectionViewCell. I can get the cell of outer collectionView however, compiler is not executing inner cell. How can I get both the cells?
P.S I am new at this.
CollectionViewController Class:
class CollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout{
#IBOutlet var collectionView1: UICollectionView!
var coll2 = CollectionViewCell()
override func viewDidLoad() {
super.viewDidLoad()
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: 150)
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)as! CollectionViewCell
cell.backgroundColor = UIColor.black
return cell
}
}
CollectionViewCell CLass:
class CollectionViewCell: UICollectionViewCell {
#IBOutlet var collectionView2: UICollectionView!
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView2.frame.width, height: 150)
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell1 = collectionView.dequeueReusableCell(withReuseIdentifier: "cell2", for: indexPath)as! CollectionViewCell2
cell1.backgroundColor = UIColor.red
return cell1
}
enter image description here
}

Answer 1

set the delegates and data source of inner collection view to the first collection view cell.
override func awakeFromNib()
{
super.awakeFromNib()
// Initialization code
self.collectionView2?.delegate = self
self.collectionView2?.dataSource = self
}

Answer 2

The reason why CollectionViewCell is not setting up the collectionView2 is because you didn't set delegate and dataSource properties of collectionView2 to the instance of CollectionViewCell.
I have created a method called setupViews in CollectionViewCell so that it can be called when you are dequeuing a CollectionViewCell in CollectionViewController so that the delegate and dataSource are being setup properly.
class CollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: 150)
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)as! CollectionViewCell
cell.backgroundColor = UIColor.black
cell.setupViews() // added this call
return cell
}
}
class CollectionViewCell: UICollectionViewCell, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
#IBOutlet weak var collectionView2: UICollectionView!
// added this method
func setupViews() {
collectionView2.delegate = self
collectionView2.dataSource = self
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView2.frame.width, height: 150)
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell1 = collectionView.dequeueReusableCell(withReuseIdentifier: "cell2", for: indexPath)
cell1.backgroundColor = UIColor.red
return cell1
}
}