Presentation of predefined UICollectionView cells (iOS 14)

CellAttributesShowcaseListViewController.md

UICellAccessory

Predefined cell accessories for UICollectionViewListCell.

CellAttributesShowcaseListViewController.swift

import UIKit

class CellAttributesShowcaseListViewController: UICollectionViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.collectionViewLayout = listLayout
        
        applyInitialSnapshot()
    }
  
    private var listLayout: UICollectionViewCompositionalLayout {
        let listConfiguration = UICollectionLayoutListConfiguration(appearance: .grouped) // .plain, .grouped, .insetGrouped, .sidebar, .sidebarPlain
        
        return UICollectionViewCompositionalLayout.list(using: listConfiguration)
    }
    
    private var cellRegistration: UICollectionView.CellRegistration<UICollectionViewListCell, String> {
        UICollectionView.CellRegistration { (cell: UICollectionViewListCell, indexPath: IndexPath, itemIdentifier: String) in
            var contentConfiguration = cell.defaultContentConfiguration()
            contentConfiguration.secondaryText = "collectionView.dataSource."
            contentConfiguration.text = itemIdentifier

            switch indexPath.row {
            case 0:
                cell.accessories = [.disclosureIndicator(displayed: .always)]
            case 1:
                cell.accessories = [.outlineDisclosure()]
            case 2:
                cell.accessories = [.checkmark()]
            case 3:
                cell.accessories = [.delete(displayed: .whenNotEditing)]
            case 4:
                cell.accessories = [.insert(displayed: .always)]
            case 5:
                cell.accessories = [.reorder(displayed: .always)]
            case 6:
                cell.accessories = [.multiselect(displayed: .always)]
            case 7:
                cell.accessories = [.label(text: "label")]
            default:
                cell.accessories = [.outlineDisclosure()]
                break
            }
            
            cell.contentConfiguration = contentConfiguration
        }
    }
    
    private func makeDataSource() -> UICollectionViewDiffableDataSource<Int, String> {
        return UICollectionViewDiffableDataSource<Int, String>(collectionView: collectionView) { (collectionView: UICollectionView, indexPath: IndexPath, itemIdentifier: String) in
            collectionView.dequeueConfiguredReusableCell(using: self.cellRegistration, for: indexPath, item: itemIdentifier)
        }
    }
    
    private func applyInitialSnapshot() {
        var snapshot = NSDiffableDataSourceSnapshot<Int, String>()
        snapshot.appendSections([0])
        snapshot.appendItems(CellData.sampleData.map { $0.title })
        
        let dataSource = makeDataSource()
        dataSource.apply(snapshot)
        
        collectionView.dataSource = dataSource
    }
}

struct CellData {
    let title: String
    let subtitle: String?
}

#if DEBUG
extension CellData {
    static let sampleData = [
        CellData(title: ".disclosureIndicator", subtitle: "a disclosure indicator system accessory with the specified display state and configuration options"),
        CellData(title: ".outlineDisclosure", subtitle: "an outline disclosure system accessory with the specified display state, configuration options, and optional action handler"),
        CellData(title: ".checkmark", subtitle: "a checkmark system accessory with the specified display state and configuration options"),
        CellData(title: ".delete", subtitle: "a delete system accessory with the specified display state, configuration options, and optional action handler"),
        CellData(title: ".insert", subtitle: "an insert system accessory with the specified display state, configuration options, and optional action handler"),
        CellData(title: ".reorder", subtitle: "a reorder system accessory with the specified display state and configuration options"),
        CellData(title: ".multiselect", subtitle: "a multiselect system accessory with the specified display state and configuration options"),
        CellData(title: ".label", subtitle: "a label system accessory with the specified text, display state, and configuration options"),
        CellData(title: ".customView", subtitle: "a custom view accessory"),
    ]
}
#endif