// UICollectionViewExtensions.swift - Copyright 2024 SwifterSwift
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#if canImport(UIKit) && !os(watchOS)
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import UIKit
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// MARK: - Properties
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public extension UICollectionView {
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/// SwifterSwift: Index path of last item in collectionView.
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var indexPathForLastItem: IndexPath? {
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return indexPathForLastItem(inSection: lastSection)
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}
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/// SwifterSwift: Index of last section in collectionView.
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var lastSection: Int {
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return numberOfSections > 0 ? numberOfSections - 1 : 0
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}
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}
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// MARK: - Methods
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public extension UICollectionView {
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/// SwifterSwift: Number of all items in all sections of collectionView.
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///
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/// - Returns: The count of all rows in the collectionView.
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func numberOfItems() -> Int {
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var section = 0
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var itemsCount = 0
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while section < numberOfSections {
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itemsCount += numberOfItems(inSection: section)
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section += 1
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}
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return itemsCount
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}
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/// SwifterSwift: IndexPath for last item in section.
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///
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/// - Parameter section: section to get last item in.
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/// - Returns: optional last indexPath for last item in section (if applicable).
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func indexPathForLastItem(inSection section: Int) -> IndexPath? {
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guard section >= 0 else {
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return nil
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}
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guard section < numberOfSections else {
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return nil
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}
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guard numberOfItems(inSection: section) > 0 else {
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return IndexPath(item: 0, section: section)
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}
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return IndexPath(item: numberOfItems(inSection: section) - 1, section: section)
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}
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/// SwifterSwift: Reload data with a completion handler.
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///
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/// - Parameter completion: completion handler to run after reloadData finishes.
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func reloadData(_ completion: @escaping () -> Void) {
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UIView.animate(withDuration: 0, animations: {
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self.reloadData()
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}, completion: { _ in
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completion()
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})
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}
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/// SwifterSwift: Dequeue reusable UICollectionViewCell using class name.
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///
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/// - Parameters:
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/// - name: UICollectionViewCell type.
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/// - indexPath: location of cell in collectionView.
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/// - Returns: UICollectionViewCell object with associated class name.
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func dequeueReusableCell<T: UICollectionViewCell>(withClass name: T.Type, for indexPath: IndexPath) -> T {
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guard let cell = dequeueReusableCell(withReuseIdentifier: String(describing: name), for: indexPath) as? T else {
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fatalError(
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"Couldn't find UICollectionViewCell for \(String(describing: name)), make sure the cell is registered with collection view")
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}
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return cell
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}
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/// SwifterSwift: Dequeue reusable UICollectionReusableView using class name.
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///
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/// - Parameters:
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/// - kind: the kind of supplementary view to retrieve. This value is defined by the layout object.
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/// - name: UICollectionReusableView type.
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/// - indexPath: location of cell in collectionView.
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/// - Returns: UICollectionReusableView object with associated class name.
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func dequeueReusableSupplementaryView<T: UICollectionReusableView>(ofKind kind: String, withClass name: T.Type,
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for indexPath: IndexPath) -> T {
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guard let cell = dequeueReusableSupplementaryView(
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ofKind: kind,
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withReuseIdentifier: String(describing: name),
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for: indexPath) as? T else {
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fatalError(
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"Couldn't find UICollectionReusableView for \(String(describing: name)), make sure the view is registered with collection view")
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}
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return cell
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}
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/// SwifterSwift: Register UICollectionReusableView using class name.
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///
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/// - Parameters:
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/// - kind: the kind of supplementary view to retrieve. This value is defined by the layout object.
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/// - name: UICollectionReusableView type.
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func register<T: UICollectionReusableView>(supplementaryViewOfKind kind: String, withClass name: T.Type) {
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register(T.self, forSupplementaryViewOfKind: kind, withReuseIdentifier: String(describing: name))
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}
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/// SwifterSwift: Register UICollectionViewCell using class name.
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///
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/// - Parameters:
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/// - nib: Nib file used to create the collectionView cell.
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/// - name: UICollectionViewCell type.
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func register(nib: UINib?, forCellWithClass name: (some UICollectionViewCell).Type) {
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register(nib, forCellWithReuseIdentifier: String(describing: name))
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}
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/// SwifterSwift: Register UICollectionViewCell using class name.
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///
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/// - Parameter name: UICollectionViewCell type.
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func register<T: UICollectionViewCell>(cellWithClass name: T.Type) {
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register(T.self, forCellWithReuseIdentifier: String(describing: name))
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}
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/// SwifterSwift: Register UICollectionReusableView using class name.
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///
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/// - Parameters:
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/// - nib: Nib file used to create the reusable view.
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/// - kind: the kind of supplementary view to retrieve. This value is defined by the layout object.
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/// - name: UICollectionReusableView type.
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func register(nib: UINib?, forSupplementaryViewOfKind kind: String,
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withClass name: (some UICollectionReusableView).Type) {
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register(nib, forSupplementaryViewOfKind: kind, withReuseIdentifier: String(describing: name))
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}
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/// SwifterSwift: Register UICollectionViewCell with .xib file using only its corresponding class.
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/// Assumes that the .xib filename and cell class has the same name.
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///
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/// - Parameters:
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/// - name: UICollectionViewCell type.
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/// - bundleClass: Class in which the Bundle instance will be based on.
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func register(nibWithCellClass name: (some UICollectionViewCell).Type, at bundleClass: AnyClass? = nil) {
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let identifier = String(describing: name)
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var bundle: Bundle?
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if let bundleName = bundleClass {
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bundle = Bundle(for: bundleName)
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}
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register(UINib(nibName: identifier, bundle: bundle), forCellWithReuseIdentifier: identifier)
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}
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/// SwifterSwift: Safely scroll to possibly invalid IndexPath.
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///
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/// - Parameters:
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/// - indexPath: Target IndexPath to scroll to.
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/// - scrollPosition: Scroll position.
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/// - animated: Whether to animate or not.
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func safeScrollToItem(at indexPath: IndexPath, at scrollPosition: UICollectionView.ScrollPosition, animated: Bool) {
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guard indexPath.item >= 0,
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indexPath.section >= 0,
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indexPath.section < numberOfSections,
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indexPath.item < numberOfItems(inSection: indexPath.section) else {
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return
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}
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scrollToItem(at: indexPath, at: scrollPosition, animated: animated)
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}
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/// SwifterSwift: Check whether IndexPath is valid within the CollectionView.
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///
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/// - Parameter indexPath: An IndexPath to check.
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/// - Returns: Boolean value for valid or invalid IndexPath.
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func isValidIndexPath(_ indexPath: IndexPath) -> Bool {
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return indexPath.section >= 0 &&
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indexPath.item >= 0 &&
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indexPath.section < numberOfSections &&
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indexPath.item < numberOfItems(inSection: indexPath.section)
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}
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}
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#endif
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