CollectionView sizeForItemAtIndexPath never called

Question

This is driving me crazy! I have a UICollectionViewController as shown below:

class PhrasesCompactCollectionViewController: UICollectionViewController
         


        

Answer 1

First class need confirm to UICollectionViewDelegateFlowLayout. Then you need to write following code in viewDidLoad():

//To tell the UICollectionView to use your UIViewController's UICollectionViewDelegateFlowLayout methods

collectionView.delegate = self

// If you want to set your own collection view flow layout

let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .vertical //depending upon direction of collection view

self.collectionView?.setCollectionViewLayout(layout, animated: true)

By using this code UICollectionViewDelegateFlowLayout method

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize

will get called, you can set size in this method.