我正在尝试向我的应用程序添加一项功能,该功能需要以设定的时间间隔获取用户的当前位置。问题是每当我使用 System.Threading.Timer 时,创建一个新的 System.Threading.Thread 并使用 Thread.Sleep() ,或使用 NSTimer.CreateScheduledTimer 当应用程序在后台时,应用程序将停止 CLLocationManager 运行。
LocationManager.cs
public class LocationManager
{
protected CLLocationManager locationManager;
/// <summary>
/// Time in milliseconds between location checking.
/// </summary>
private int serviceMillisecondTimeout = 10000;
public LocationManager()
{
this.locationManager = new CLLocationManager();
// iOS 8 additional permissions requirements
if (UIDevice.CurrentDevice.CheckSystemVersion(8, 0))
{
locationManager.RequestAlwaysAuthorization();
}
locationManager.LocationsUpdated += onLocationUpdated;
locationManager.DistanceFilter = 1;
locationManager.DesiredAccuracy = 1;
}
public CLLocationManager LManager
{
get { return locationManager; }
}
public void startLocationUpdates()
{
if (CLLocationManager.LocationServicesEnabled)
{
locationManager.StartUpdatingLocation();
}
}
public void stopLocationUpdates()
{
locationManager.StopUpdatingLocation();
}
public void onLocationUpdated(object sender, CLLocationsUpdatedEventArgs e)
{
// stop location updates until timer calls StartUpdatingLocation
locationManager.StopUpdatingLocation();
var coordinate = e.Locations[e.Locations.Length - 1].Coordinate;
double lat = coordinate.Latitude;
double lon = coordinate.Longitude;
// do stuff with coordinates
// This will work until the application goes into the background.
// The same thing seems to happen whenever I try creating
// new threads, or any other form of a timer.
//
// Without any sort of timer or new thread, it will call
// StartUpdatingLocation in the background and will
// continue to run indefinitely.
NSTimer t = NSTimer.CreateScheduledTimer(TimeSpan.FromMilliseconds(serviceMillisecondTimeout), delegate
{
if (CLLocationManager.LocationServicesEnabled)
{
locationManager.StartUpdatingLocation();
}
});
}
}
如何设置明确的时间间隔并仍然能够在后台运行位置更新?
Best Answer-推荐答案 strong>
平台不支持此功能。您可以在后台或离开设置的地理围栏时订阅重要的位置更改,但您不能强制您的代码在后台以特定间隔获取位置修复。这是 iOS 平台的限制/限制,您对此无能为力。
最接近你想要的可能是Getting Location Events in the Background .
关于ios - Xamarin iOS - CLLocationManager 在后台以设定的时间间隔获取位置,我们在Stack Overflow上找到一个类似的问题:
https://stackoverflow.com/questions/31949539/
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