Question

didUpdateLocations被多次调用。所以我怎么能处理这个。我尝试在locationManager.stopUpdatingLocation()中使用didUpdateLocations，但效果不佳。

override func viewDidLoad()
{
    super.viewDidLoad()
    //for Authorisation from the User.
    isAuthorizedtoGetUserLocation()

    if CLLocationManager.locationServicesEnabled() {
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.startUpdatingLocation()
    }
}

func isAuthorizedtoGetUserLocation() {

    if CLLocationManager.authorizationStatus() != .authorizedWhenInUse     {
        locationManager.requestWhenInUseAuthorization()
    }
}

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    locationManager.stopUpdatingLocation()
    let locValue:CLLocationCoordinate2D = manager.location!.coordinate
    print("locations = \(locValue.latitude) \(locValue.longitude)")

    let camera = GMSCameraPosition.camera(withLatitude: locValue.latitude, longitude: locValue.longitude, zoom: 6.0)
    let mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
    self.view = mapView

    // Creates a marker in the center of the map.
    let marker = GMSMarker()
    marker.position = CLLocationCoordinate2D(latitude: locValue.latitude, longitude: locValue.longitude)
    marker.title = "name"
    marker.map = mapView

}

错误的错误代码

func locationManager( _ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    manager.stopUpdatingLocation()
    manager = nil // Here it is giving error "Cannot assign to value: 'manager' is a 'let' constant"

    var newLocation: CLLocation? = locations.last
    var locationAge: TimeInterval? = -(newLocation?.timestamp.timeIntervalSinceNow)!
    if Double(locationAge!) > 5.0 {
        return
    }
    if Double((newLocation?.horizontalAccuracy)!) < 0 {
        return
    }


    //manager = nil
    let locValue:CLLocationCoordinate2D = manager.location!.coordinate
    print("locations = \(locValue.latitude) \(locValue.longitude)")

    let camera = GMSCameraPosition.camera(withLatitude: locValue.latitude, longitude: locValue.longitude, zoom: 6.0)
    let mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
    self.view = mapView

    // Creates a marker in the center of the map.
    let marker = GMSMarker()
    marker.position = CLLocationCoordinate2D(latitude: locValue.latitude, longitude: locValue.longitude)
    marker.title = "name"
    marker.map = mapView

}

Answer 1

您需要设置CLLocation manager的distanceFilter属性，如下所示：

/* Notify changes when device has moved x meters.
 * Default value is kCLDistanceFilterNone: all movements are reported.
 */
self.locationManager.distanceFilter = 10.0f; // you can change as per your require ment

Answer 2

这是另一种方法。我的应用程序需要在更改后上传位置。即使我这样声明距离过滤器：

locationManager.distanceFilter = 300

首次创建CLLocationManager或调用startUpdatingLocation（）时，它可能会多次调用。

所以我将它们放在这样的任务队列中：

     if let locationUploadTask = self.locationTask { // if there is a task waiting, cancel it 
            locationUploadTask.cancel()
        }

     self.locationTask = DispatchWorkItem { //create a new task for upload
            //do your task
        }

     DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 1, execute: self.locationTask!) //execute the task 1 second after

此代码强制您的代码等待1秒。如果在一秒钟内有新的位置更新，则取消当前任务，再次开始等待1秒钟。

Answer 3

将属性distanceFilter设置为最大恒定距离CLLocationDistanceMax，以指示只有在设备移动了相当大的距离后才应触发新的更新。

CLLocationManager didUpdateLocations被多次调用

3 个答案: