Question

我是Xcode和Swift的新手，我正在尝试简单地创建一个显示用户当前位置并更新它的地图。到目前为止我有这个：

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

    @IBOutlet weak var map: MKMapView!

    let locationManager = CLLocationManager()
    var mapp = MKMapView.self

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        if (CLLocationManager.locationServicesEnabled())
        {
            self.locationManager.delegate = self
            self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
            self.locationManager.requestWhenInUseAuthorization()
            self.locationManager.startUpdatingLocation()
            self.map.showsUserLocation = true
        }
        else
        {
            print("Location services are not enabled")
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    override func loadView() {
        //let camera = GMSCameraPosition.camera(withLatitude: 36.2108, longitude: -81.6774, zoom: 15.0)
        //let mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
        //mapView.isMyLocationEnabled = true
        //view = mapView
    }


    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
    {
        let location = locations.last
        let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
        let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.002, longitudeDelta: 0.002))
        self.map.setRegion(region, animated: true)
        self.locationManager.stopUpdatingLocation()
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error)
    {
        print("Errors: " + error.localizedDescription)
    }
}

我在故事板中制作了MapView，CTRL将其拖动到文件中（因此@IBOutlet弱变量映射：MKMapView！）。但是，当我插入手机并模拟应用程序时，它会在打开一个可选值时显示出一个＆＃34;意外发现的nil＆＃34;在一些打印语句之后，我发现每当我引用map变量时都会发生这种情况。为什么是这样？谢谢！

Answer 1

在原帖的评论中，罗布回答了这个问题：

“
删除loadView方法。只有在以编程方式创建视图时才使用它。使用故事板（或NIB）时，将配置代码放在viewDidLoad中，而不是loadView。 - 罗布“

谢谢Rob

MKMapView似乎是零？

1 个答案: