ios - 在 iOS 中放大用户位置

Question

我已经尝试解决这个问题几个小时了，但我似乎无法找到解决方案。我正在尝试在我的 map View 上创建一个按钮，该按钮在按下时放大用户位置。以下是与按钮相关的功能代码:

func zoomInOnLocation() {
    let userLocation = MKUserLocation()
    let locationManager = CLLocationManager()
    locationManager.requestWhenInUseAuthorization()

    let currentLocation: CLLocation? = userLocation.location
    let latitude = currentLocation?.coordinate.latitude
    let longitude = currentLocation?.coordinate.longitude
    let span: MKCoordinateSpan = MKCoordinateSpan(latitudeDelta: 0.05, longitudeDelta: 0.05)
    let location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude!, longitude!)
    let region: MKCoordinateRegion = MKCoordinateRegionMake(location, span)
    mapView.setRegion(region, animated: true)
}

当我点击模拟器中的按钮时，我收到一条错误，指出 fatal error :

unexpectedly found nil while unwrapping an Optional value

第五行 mapDelegate.mapView!... 以红色突出显示。此外，我还向 Info.plist 添加了正确的标签。非常感谢任何帮助。

Answer 1

检查这个:

 if #available(iOS 9.0, *) {
    locationManager.requestLocation()
  } else {
    // Fallback
  }

 let latitude:CLLocationDegrees = //insert latitutde

let longitude:CLLocationDegrees = //insert longitude

let latDelta:CLLocationDegrees = 0.05

let lonDelta:CLLocationDegrees = 0.05

let span = MKCoordinateSpanMake(latDelta, lonDelta)

let location = CLLocationCoordinate2DMake(latitude, longitude)

let region = MKCoordinateRegionMake(location, span)

mapView.setRegion(region, animated: false)

更多信息:Making the map zoom to user location and annotation (swift 2)