如何将MapView添加到Swift中的另一个视图？

import MapKit

class ViewController: UIViewController {
    var mapView: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        mapView = MKMapView(frame: view.bounds)
        view.addSubview(mapView)
    }
}

class ViewController: UIViewController, MKMapViewDelegate {
    var mapView: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        mapView = MKMapView(frame: view.bounds)
        mapView.delegate = self
        view.addSubview(mapView)
    }

    // 实现MKMapViewDelegate协议中的方法
    // ...
}

class ViewController: UIViewController, MKMapViewDelegate {
    var mapView: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        mapView = MKMapView(frame: view.bounds)
        mapView.delegate = self
        view.addSubview(mapView)

        // 设置地图的中心坐标和缩放级别
        let coordinate = CLLocationCoordinate2D(latitude: 37.7749, longitude: -122.4194)
        let span = MKCoordinateSpan(latitudeDelta: 0.1, longitudeDelta: 0.1)
        let region = MKCoordinateRegion(center: coordinate, span: span)
        mapView.setRegion(region, animated: true)

        // 添加标注
        let annotation = MKPointAnnotation()
        annotation.coordinate = coordinate
        annotation.title = "San Francisco"
        mapView.addAnnotation(annotation)
    }

    // 实现MKMapViewDelegate协议中的方法
    // ...
}