如何将一个MKPointAnnotation变成一个按钮？

import MapKit

class CustomAnnotationView: MKAnnotationView {
    var button: UIButton!

    override init(annotation: MKAnnotation?, reuseIdentifier: String?) {
        super.init(annotation: annotation, reuseIdentifier: reuseIdentifier)
        
        // 创建按钮
        button = UIButton(type: .custom)
        button.frame = CGRect(x: 0, y: 0, width: 30, height: 30)
        button.setTitle("按钮", for: .normal)
        button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
        
        // 设置按钮样式
        button.backgroundColor = UIColor.blue
        button.layer.cornerRadius = button.frame.width / 2
        
        // 将按钮添加到自定义的MKAnnotationView中
        addSubview(button)
    }
    
    @objc func buttonTapped() {
        // 按钮点击事件处理
        print("按钮被点击了")
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

// 在MKMapViewDelegate的方法中使用自定义的CustomAnnotationView
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
    if annotation is MKPointAnnotation {
        let identifier = "CustomAnnotation"
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier)
        
        if annotationView == nil {
            annotationView = CustomAnnotationView(annotation: annotation, reuseIdentifier: identifier)
        } else {
            annotationView?.annotation = annotation
        }
        
        return annotationView
    }
    
    return nil
}