滚动视图中的循环重置(swift3)

import UIKit

class ViewController: UIViewController, UIScrollViewDelegate {
    @IBOutlet weak var scrollView: UIScrollView!
    
    let numberOfElements = 5
    var elementWidth: CGFloat = 0.0
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        scrollView.delegate = self
        scrollView.isPagingEnabled = true
        
        // 计算每个元素的宽度
        elementWidth = scrollView.frame.width
        
        // 设置滚动视图的内容大小
        scrollView.contentSize = CGSize(width: elementWidth * CGFloat(numberOfElements), height: scrollView.frame.height)
        
        // 添加元素到滚动视图中
        for i in 0..<numberOfElements {
            let elementView = UIView(frame: CGRect(x: CGFloat(i) * elementWidth, y: 0, width: elementWidth, height: scrollView.frame.height))
            elementView.backgroundColor = UIColor.random()
            scrollView.addSubview(elementView)
        }
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let contentOffsetX = scrollView.contentOffset.x
        
        // 判断是否已经滚动到最后一个元素的位置
        if contentOffsetX >= CGFloat(numberOfElements - 1) * elementWidth {
            // 重置滚动视图的偏移量为第一个元素的位置
            scrollView.contentOffset = CGPoint(x: 0, y: 0)
        }
    }
}

extension UIColor {
    static func random() -> UIColor {
        let red = CGFloat.random(in: 0...1)
        let green = CGFloat.random(in: 0...1)
        let blue = CGFloat.random(in: 0...1)
        return UIColor(red: red, green: green, blue: blue, alpha: 1.0)
    }
}