自定义TableViewCell的UIimageView宽度为单元格宽度的1/3，单元格高度=图像纵横比

class CustomTableViewCell: UITableViewCell {
    var customImageView: UIImageView!
    
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        // 初始化自定义的UIImageView
        customImageView = UIImageView()
        customImageView.contentMode = .scaleAspectFit
        contentView.addSubview(customImageView)
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        // 设置UIImageView的frame属性
        let imageViewWidth = contentView.frame.width / 3
        let imageViewHeight = imageViewWidth / imageAspectRatio() // 图像纵横比
        let imageViewX = contentView.frame.width - imageViewWidth
        let imageViewY = (contentView.frame.height - imageViewHeight) / 2
        customImageView.frame = CGRect(x: imageViewX, y: imageViewY, width: imageViewWidth, height: imageViewHeight)
    }
    
    // 计算图像纵横比
    private func imageAspectRatio() -> CGFloat {
        // 假设图像的宽度和高度已知
        let imageWidth: CGFloat = 300
        let imageHeight: CGFloat = 200
        return imageHeight / imageWidth
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}