UICollectionView.reloadData() do NOT trigger UICollectionDataSource methods

Question

Here is the code, where i set DataSource for CollectionView:

override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        collectionView.dataSource = ProductDataSource(products: createAllProductsList())
        collectionView.reloadData()
    }

DataSource class is conform to UICollectionViewDataSource protocol. Code compiles with no troubles. But i see empty collection view instead of my 5 elements. ReloadData don't trigger methods from DataSource.

Swift 3, XCode 8

Answer 1

Create an instance variable of ProductDataSource in the current class and then set it as data source that will fix the issue. The object does not have a strong pointer to it in the current case and hence the data source gets nullified.