add custom header to collection view swift

I am trying to add header to collectionView using custom xib file. I created the xib file with class implementing UICollectionReusableView. In collectionViewController I registered the xib file like this:

self.collectionView.register(UINib(nibName: HCollectionReusableView.nibName, bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: HCollectionReusableView.reuseIdentifier)

and after that in viewForSupplementaryElementOfKind I did

let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: HCollectionReusableView.reuseIdentifier, for: indexPath) as! HCollectionReusableView

and for sizing

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
    return CGSize(width: 100, height: 50)
}

I am getting error: Could not load NIB in bundle. any missing code ?

HCollectionReusableView class:

class HCollectionReusableView: UICollectionReusableView {

static var nibName : String
    {
    get { return "headerNIB"}
}

static var reuseIdentifier: String
    {
    get { return "headerCell"}
}



override func awakeFromNib() {
    super.awakeFromNib()
    // Initialization code
}

}

You need to call viewForSupplementaryElementOfKind like this:

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

    switch kind {
    case UICollectionElementKindSectionHeader:
           let reusableview = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "HCollectionReusableView", for: indexPath) as! HCollectionReusableView

            reusableview.frame = CGRect(0 , 0, self.view.frame.width, headerHight)
         //do other header related calls or settups
            return reusableview


    default:  fatalError("Unexpected element kind")
    }
}

This way you can initialise and show the header

Another way of setting the UICollectionViewHeader frame is by extending UICollectionViewDelegateFlowLayout like this:

extension UIViewController: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 100) //add your height here
    }
}

This removes the need to call :

reusableview.frame = CGRect(0 , 0, self.view.frame.width, headerHight)

in the above mentioned

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView

Remember to register the HeaderView after you initialise your UICollectionView by calling:

collectionView.register(UINib(nibName: HCollectionReusableView.nibName, bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "HCollectionReusableView")

Swift 4.1 Update

UICollectionElementKindSectionHeader has been renamed to UICollectionView.elementKindSectionHeader