ios - 我的 CLLocation 做错了什么？

Question

我正在尝试制作一个简单的应用程序来显示: 纬度 经度 水平精度 高度 垂直精度 起点位置

我的代码是:

@IBOutlet weak var latitude: UILabel!
@IBOutlet weak var longitude: UILabel!
@IBOutlet weak var horizontalAccuracy: UILabel!
@IBOutlet weak var altitude: UILabel!
@IBOutlet weak var verticalAccuracy: UILabel!
@IBOutlet weak var distance: UILabel!

var locationManager: CLLocationManager = CLLocationManager()
var startLocation: CLLocation!

@IBAction func resetDistance(sender: AnyObject) {
    startLocation = nil
}

func locationManager(manager: CLLocationManager!,
    didUpdateLocations locations: [AnyObject]!)
{
    var latestLocation: AnyObject = locations[locations.count - 1]

    latitude.text = String(format: "%.4f",
        latestLocation.coordinate.latitude)
    longitude.text = String(format: "%.4f",
        latestLocation.coordinate.longitude)
    horizontalAccuracy.text = String(format: "%.4f",
        latestLocation.horizontalAccuracy)
    altitude.text = String(format: "%.4f",
        latestLocation.altitude)
    verticalAccuracy.text = String(format: "%.4f",
        latestLocation.verticalAccuracy)


    if startLocation == nil {
        startLocation = latestLocation as! CLLocation
    }

    var distanceBetween: CLLocationDistance =
    latestLocation.distanceFromLocation(startLocation)

    distance.text = String(format: "%.2f", distanceBetween)
} 


func locationManager(manager: CLLocationManager!,
    didFailWithError error: NSError!) {

}

然后在 ViewDidLoad 部分:

locationManager.desiredAccuracy = kCLLocationAccuracyBest
    locationManager.delegate = self
    locationManager.requestWhenInUseAuthorization()
    locationManager.startUpdatingLocation()
    startLocation = nil

我一直收到错误:在 latitude.text 行上(一切都正确连接)

fatal error: unexpectedly found nil while unwrapping an Optional value

(数据库)

我将如何添加 if let 语句？你能帮我找出问题所在吗？

谢谢!

Answer 1

欢迎使用 swift 。您不能对 AnyObject 做任何事情。像这样放下:

    let latestLocation = locations.last as! CLLocation

此外，您说“一切都正确连接”，但我不确定我是否相信；尝试执行 println(latitude) 以确保。

最后，这段代码是行不通的:

locationManager.requestWhenInUseAuthorization()
locationManager.startUpdatingLocation()

问题是授权请求是异步的。因此，您可能在实际获得授权之前就开始更新位置。在开始请求更新之前，您必须等到您真正拥有授权。