Why

iOS13 publish UICollectionViewDiffableDataSource/UITableViewDiffableDataSource, lead to a more convenient way to deal to data on collection view/table view

Benefit

1. Reduce code
2. Automatic animation
3. Data Synchronization → You have to manually handle the data change between collection/table view and datasource

How to use

1. Create sections/items

   • Enum is a great way to create sections data

2. Create UICollectionViewDiffableDataSource<Section, Item> instance

   • Generic which need to provide Section/Item data

   • Use typealias to shorten the type name

     typealias DataSource = UICollectionViewDiffableDataSource<Section, Item>
     

3. configure data source

   1. init(collectionView:cellProvider:)

      • collectionView → the collectionView which connect your data with(diffable data source)

      • cellProvider → where you can configure the cell content

        pretty much the same behavior collectionView(_:numberOfItemsInSection:) collectionView(_:cellForItemAt:)

   func configureDataSource() -> DataSoure {
   	let dataSource = DataSource(collectionView: collectionView) { collectionView, indexPath, video -> UICollectionViewCell? in
       let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "VideoCollectionViewCell", for: indexPath) as? VideoCollectionViewCell
       cell?.video = video
       return cell
     }
     return dataSource
   }
   

4. Using NSDiffableDataSourceSnapshot

   • Store Section/Item to display

   • Use typealias to shorten the type name

     typealias Snapshot = NSDiffableDataSourceSnapshot<Section, Item>
     

   • Append section/item, then apply to your dataSource

     var snapshot = Snapshot()
     // 要裝入sections/items
     snapshot.appendSections([.main])
     snapshot.appendItems(videoList)
     // snapshot.appendItems(list, toSection: .main)
     dataSource.apply(snapshot, animatingDifferences: animatingDifferencecs)
     

Alert

Demo