Question

我正在尝试创建一个简单的应用程序，显示：纬度经度水平精度高度垂直精度位置从开始

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（所有内容都正确连接）

fatal error: unexpectedly found nil while unwrapping an Optional value

（lldb）

我如何添加 if 语句？你能帮我找到问题吗？

谢谢！

Answer 1

欢迎来到Swift。你不能用AnyObject做任何事情。像这样抛弃：

    let latestLocation = locations.last as! CLLocation

另外，你说＆＃34;一切都正确连接了＃34;但是我不确定我是否相信;尝试println(latitude)来确保。

最后，这段代码不起作用：

locationManager.requestWhenInUseAuthorization()
locationManager.startUpdatingLocation()

问题是授权请求是异步。因此，您可能在实际获得授权之前开始更新位置。在开始要求更新之前，您必须等到实际拥有授权。

Answer 2

关于如何获取授权：

首先将 NSLocationWhenInUseUsageDescription 添加到info.plist文件中

然后在viewDidload中：

if NSString(string:UIDevice.currentDevice().systemVersion).doubleValue > 8 {
        locationManager.requestWhenInUseAuthorization()
    }

然后是这个委托方法，启动updateingLoation

 func locationManager(manager: CLLocationManager!, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
        if status != CLAuthorizationStatus.Denied{
            locationManager.startUpdatingLocation()
        }
    }

然后，当您获得位置时，可以将其转换为CLLocation matt 帖子

您也可以参考此链接了解详细信息，这是我之前回答的答案 Swift: Exception while trying to print CLLocationSpeed "unexpectedly found nil while unwrapping an Optional value"

我的CLLocation我做错了什么？

2 个答案: