Collection Views didn’t exactly make their way into SwiftUI during WWDC 2020, but that didn’t stop UICollectionView from receiving some powerful new updates.

CompositionalLayouts and DiffableDataSources were introduced in iOS 13 CollectionViews and brought more flexibility in constructing layouts and data sources for our UICollectionView.

With iOS 14, there are three new additions to the CollectionView APIs for layouts, data sources, and cells — the three pillars of constructing collection views:

• Lists are a new addition to CompositionalLayouts and bring a UITableView-like appearance in CollectionViews.
• UICollectionView.CellRegistration lets you configure cells in a completely different way using new Configuration APIs. Also, there’s a new UICollectionViewListCell concrete class that provides cells with list-like content styling by default.
• Diffable Data Source now includes Section Snapshots to allow more updating data on a per-section basis. This is useful in building Outlined Styled lists, a new hierarchical design introduced in iOS 14.

In the next few sections, we’ll discuss the first two additions. Let’s see how to construct layouts and cells in UICollectionView in the new iOS 14 way.

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iOS 14 Cell Configuration and Registration

iOS 14 introduces a brand new Cell Configuration API for configuring our CollectionView and TableView cells.

This means that we don’t need to set properties directly on the UITableViewCell and UICollectionViewCell like we did earlier.

The new configuration API lets us use a content configuration to set the cell’s content and styling or update it based on different states:

let cellRegistration = UICollectionView.CellRegistration<UICollectionViewCell, String> { cell, indexPath, name in

	            var content = UIListContentConfiguration.cell()
	            content.text = name
	            cell.contentConfiguration = content
	}

For UICollectionViews, we have a new UICollectionViewListCell. We can directly fetch its default configuration in the following way:

var content = listCell.defaultContentConfiguration()

In doing so, we’re able to get rid of using cell identifiers and the obligatory if let and guard let statements we used to write to ensure that the cell was registered.

More importantly, we’re not directly accessing the cell’s label and image property anymore, which allows us to compose configurations that can be used across TableView, CollectionView, and custom cells.

Aside from contentConfiguration, there’s also a backgroundConfigurationthat we can leverage to set background appearance properties and also a leadingSwipeActionsConfiguration and trailingSwipeActionsConfigurationto easily embed UITableView-like swipe behavior directly in our UICollectionView cell implementation.

The new UICollectionView.CellRegistration structure that we just created automatically takes care of cell registration when passed inside the dequeueConfiguredReusableCell. You don’t need to register cells using identifiers anymore.

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