CollectionView is not displaying vertically as expected - ios

Question

I am trying to implement following screen.
But in my code, it is displaying following way
following code I wrote,
import UIKit
class LunchViewController: UIViewController {
#IBOutlet weak var mainCollectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
}
extension LunchViewController:UICollectionViewDataSource,UICollectionViewDelegateFlowLayout,UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 412, height: 180)
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
// return self.myLibraryArray.count
return 8
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// let item = self.myLibraryArray[indexPath.row]
guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "RestaurantCollectionViewCell", for: indexPath) as? RestaurantCollectionViewCell else {
return UICollectionViewCell()
}
//cell.fillDetails(item)
return cell
}
}
Here is the complete project link
Can any one tell me, what is the issue? or what I have to write the code to get expected output?
Update:

Answer 1

Select collectionView and Change Estimate Size to none. In storyboard.
if you dont want space between two cells then set 0 to for lines in Min spacing
And i have given width as screen width
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: UIScreen.main.bounds.size.width, height: 180)
}
Output :-

Answer 2

Change sizeForItem method to this:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.frame.size.width, height: 180)
}
Also, make sure the mainCollectionView is constrained to the leading and trailing edges in the storyboard.