collectionView单元格图像在滚动时更改-快速编程

import UIKit

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
    
    let collectionView = UICollectionView(frame: CGRect.zero, collectionViewLayout: UICollectionViewFlowLayout())
    let cellIdentifier = "Cell"
    var images = [UIImage(named: "image1"), UIImage(named: "image2"), UIImage(named: "image3")]
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置collectionView的布局和数据源
        collectionView.collectionViewLayout = UICollectionViewFlowLayout()
        collectionView.dataSource = self
        collectionView.delegate = self
        
        // 注册单元格
        collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellIdentifier)
        
        // 添加collectionView到视图
        view.addSubview(collectionView)
        
        // 设置约束
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        collectionView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        collectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        collectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
        collectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    }
    
    // 返回单元格数量
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return images.count
    }
    
    // 返回单元格视图
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath)
        
        // 设置初始图像
        let imageView = UIImageView(image: images[indexPath.item])
        cell.contentView.addSubview(imageView)
        
        // 设置约束
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.topAnchor.constraint(equalTo: cell.contentView.topAnchor).isActive = true
        imageView.leadingAnchor.constraint(equalTo: cell.contentView.leadingAnchor).isActive = true
        imageView.trailingAnchor.constraint(equalTo: cell.contentView.trailingAnchor).isActive = true
        imageView.bottomAnchor.constraint(equalTo: cell.contentView.bottomAnchor).isActive = true
        
        return cell
    }
    
    // 监听滚动事件
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        // 计算当前可见的单元格
        let visibleCells = collectionView.visibleCells
        
        for cell in visibleCells {
            // 获取单元格的索引
            if let indexPath = collectionView.indexPath(for: cell) {
                // 根据需要更改单元格的图像
                let newImage = // 根据滚动偏移量计算新的图像
                let imageView = cell.contentView.subviews.first as? UIImageView
                imageView?.image = newImage
            }
        }
    }
}