Ios Swift-谷歌地图与'；意外发现nil'；错误

我正在尝试将

GoogleMap

设置为

UIView

并将其添加为子视图。但是，在运行应用程序时，我遇到以下错误：

致命错误：在展开可选值时意外发现nil

它在代码行崩溃：

mapView.camera = camera

这是我的完整ViewController代码：

class LocationViewController: UIViewController {
    @IBOutlet weak var mapView: GMSMapView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let camera = GMSCameraPosition.camera(withLatitude: 15.4989, longitude: 73.8278, zoom: 6)
        mapView.camera = camera
        mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
        mapView.isMyLocationEnabled = true
        mapView.settings.myLocationButton = true
        self.view.addSubview(self.mapView)
    }
}

我经历了一些其他类似的线程，它们都有相同的代码。在我的例子中，UI冻结并因此错误而崩溃。我做错了什么

编辑

---

是的，我已将UIView的自定义类设置为

GMSMapView

您是否可以使用以下代码并尝试：

override func viewDidLoad() {
        super.viewDidLoad()

        let camera = GMSCameraPosition.camera(withLatitude: 15.4989, longitude: 73.8278, zoom: 6)
        mapView.camera = camera
        mapView.isMyLocationEnabled = true
        mapView.settings.myLocationButton = true
        self.view.addSubview(self.mapView)
    }

let camera = GMSCameraPosition.camera(withLatitude: 15.4989,
                                      longitude:  73.8278,
                                      zoom: 6)
let mapView = GMSMapView.map(withFrame: self.view.bounds, camera: camera)

---

你必须这样做

您必须为

GMSMapview

在这一行

self.view.bounds

中，您必须设置自定义

view

let camera = GMSCameraPosition.camera(withLatitude: 15.4989,
                                      longitude:  73.8278,
                                      zoom: 6)
let mapView = GMSMapView.map(withFrame: self.view.bounds, camera: camera)

---

这是swift 3.0中的语法

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 
{
    print(locations)
    mapview.delegate = self
 currentLocation =     CLLocationCoordinate2D(latitude:CLLocationDegrees(locations[0].coordinate.latitude), longitude:CLLocationDegrees(locations[0].coordinate.longitude))
    mapview.camera = GMSCameraPosition.camera(withTarget:locations[0].coordinate, zoom: 10.0)
mapview.isMyLocationEnabled = true
}

---

你在哪一行出错？@Jecky At

mapView.camera=camera

检查我的答案检查你在故事板中的IBOutlet连接你给了故事板中的视图GMSMapView类了吗你做了什么更改？你的mapView框架swift-3中的代码有点不同bro:/仍然崩溃，应该是弱的还是强的参考？它必须是弱的，如果你已经连接它使用故事板，然后参考我的更新答案