83 lines
3.2 KiB
Swift
83 lines
3.2 KiB
Swift
//
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// ItemsViewController.swift
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// Reader
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//
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// Created by Shadowfacts on 1/9/22.
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//
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import UIKit
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import CoreData
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class ItemsViewController: UIViewController {
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let fervorController: FervorController
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let fetchRequest: NSFetchRequest<Item>
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private var collectionView: UICollectionView!
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private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
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private var resultsController: NSFetchedResultsController<Item>!
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init(fervorController: FervorController, fetchRequest: NSFetchRequest<Item>) {
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self.fervorController = fervorController
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self.fetchRequest = fetchRequest
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super.init(nibName: nil, bundle: nil)
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}
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required init?(coder: NSCoder) {
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fatalError("init(coder:) has not been implemented")
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}
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override func viewDidLoad() {
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super.viewDidLoad()
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let configuration = UICollectionLayoutListConfiguration(appearance: .plain)
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let layout = UICollectionViewCompositionalLayout.list(using: configuration)
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collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout)
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collectionView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
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view.addSubview(collectionView)
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dataSource = createDataSource()
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var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
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snapshot.appendSections([.items])
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dataSource.apply(snapshot, animatingDifferences: false)
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fetchRequest.sortDescriptors = [NSSortDescriptor(key: "published", ascending: false)]
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resultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: fervorController.persistentContainer.viewContext, sectionNameKeyPath: nil, cacheName: nil)
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resultsController.delegate = self
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try! resultsController.performFetch()
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}
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private func createDataSource() -> UICollectionViewDiffableDataSource<Section, Item> {
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let listCell = UICollectionView.CellRegistration<UICollectionViewListCell, Item> { cell, indexPath, item in
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var config = cell.defaultContentConfiguration()
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config.text = item.title
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cell.contentConfiguration = config
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cell.accessories = [.disclosureIndicator()]
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}
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let dataSource = UICollectionViewDiffableDataSource<Section, Item>(collectionView: collectionView) { collectionView, indexPath, item in
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return collectionView.dequeueConfiguredReusableCell(using: listCell, for: indexPath, item: item)
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}
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return dataSource
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}
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}
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extension ItemsViewController {
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enum Section: Hashable {
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case items
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}
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}
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extension ItemsViewController: NSFetchedResultsControllerDelegate {
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func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeContentWith snapshot: NSDiffableDataSourceSnapshotReference) {
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var snapshot = self.dataSource.snapshot()
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snapshot.deleteItems(snapshot.itemIdentifiers(inSection: .items))
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// use resultsController here instead of controller so we don't have to cast
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snapshot.appendItems(resultsController.fetchedObjects!, toSection: .items)
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self.dataSource.apply(snapshot, animatingDifferences: false)
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}
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}
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