UI元素在UIScrollView swift中不起作用

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let scrollView = UIScrollView()
        scrollView.frame = view.bounds
        scrollView.showsVerticalScrollIndicator = true
        scrollView.showsHorizontalScrollIndicator = true
        view.addSubview(scrollView)
        
        let contentView = UIView()
        contentView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.addSubview(contentView)
        
        NSLayoutConstraint.activate([
            contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
            contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
            contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
            contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
            contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor)
        ])
        
        let button = UIButton(type: .system)
        button.setTitle("Click Me", for: .normal)
        button.translatesAutoresizingMaskIntoConstraints = false
        contentView.addSubview(button)
        
        NSLayoutConstraint.activate([
            button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),
            button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor),
            button.widthAnchor.constraint(equalToConstant: 100),
            button.heightAnchor.constraint(equalToConstant: 50)
        ])
        
        scrollView.contentSize = CGSize(width: 1000, height: 1000) // 根据实际内容调整大小
    }
}