IGListKit/Examples/Examples-iOS/IGListKitExamples/ViewControllers/WorkingRangeViewController.swift

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import IGListKit
import UIKit

final class WorkingRangeViewController: UIViewController, ListAdapterDataSource {

    lazy var adapter: ListAdapter = {
        return ListAdapter(updater: ListAdapterUpdater(), viewController: self, workingRangeSize: 2)
    }()

    let collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())

    let data: [Int] = {
        var set = Set<Int>() // only use unique values
        while set.count < 20 {
            set.insert( Int(arc4random_uniform(200)) + 200 )
        }
        return Array(set)
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        view.addSubview(collectionView)
        adapter.collectionView = collectionView
        adapter.dataSource = self
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        collectionView.frame = view.bounds
    }

    // MARK: ListAdapterDataSource

    func objects(for listAdapter: ListAdapter) -> [ListDiffable] {
        return data as [ListDiffable]
    }

    func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -> ListSectionController {
        return WorkingRangeSectionController()
    }

    func emptyView(for listAdapter: ListAdapter) -> UIView? {
        return nil
    }

}