Catch Retain Cycles In Collection View Subclass

retainCycle4.swift

import UIKit

class CollectionView: UICollectionView {
    private var allCells: [WeakBox<UICollectionViewCell>] = []

    private func appendIfNotPresent(_ cell: UICollectionViewCell) {
        if allCells.first(where: { $0.unbox === cell }) == nil {
            allCells.append(WeakBox(cell))
        }
    }

    override func dequeueReusableCell(withReuseIdentifier identifier: String, for indexPath: IndexPath) -> UICollectionViewCell {
        let cell: UICollectionViewCell = super.dequeueReusableCell(withReuseIdentifier: identifier, for: indexPath)
        appendIfNotPresent(cell)
        return cell
    }

    deinit {
        allCells.forEach { MemoryChecker.verifyDealloc(object: $0.unbox) }
    }
}