ios - Xamarin iOS - CLLocationManager 在后台以设定的时间间隔获取位置

Question

我正在尝试向我的应用程序添加一项功能，该功能需要在设定的时间间隔内获取用户的当前位置。问题是每当我使用 System.Threading.Timer 时，都会创建一个新的 System.Threading.Thread 并使用 Thread.Sleep()，或使用 NSTimer.CreateScheduledTimer 应用程序将在应用程序处于后台时停止运行 CLLocationManager。

位置管理器.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();
            }
        });
    }
}

我该怎么做才能设置明确的时间间隔并仍然能够在后台运行位置更新？

Answer 1

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时间间隔获取位置修复。这是 iOS 平台的限制/限制，您无能为力。

最接近您想要的可能是 Getting Location Events in the Background .