/// <summary>
/// Stop listen to location update / gatherer device location.
/// </summary>
private void StopLocationUpdate(GeolocationStatus status)
{
if (LocationRetrieveTimer != null)
{
// Destroy the timer
LocationRetrieveTimer.Dispose();
LocationRetrieveTimer = null;
}
if (FusedLocationClient != null)
{
// Stop listen to location changes
if (FusedLocationCallback != null)
{
FusedLocationCallback.LocationResult -= FusedLocationCallback_LocationResult;
FusedLocationClient.RemoveLocationUpdates(FusedLocationCallback);
FusedLocationCallback = null;
}
FusedLocationClient.Dispose();
FusedLocationClient = null;
}
if (LocationManager != null)
{
// Stop listen to location changes
LocationManager.RemoveUpdates(this);
LocationManager.Dispose();
LocationManager = null;
}
// Make sure we only update the result if it is not completed yet
if (LocationTaskCompletionSource != null &&
!LocationTaskCompletionSource.Task.IsCompleted)
{
// Craft the location with all information we have whatever the location is acceptable or not
var location = IsLastKnownLocationFresh() ?
LastKnownLocation.ToNewGeolocation(status) :
new Geolocation(status);
// return the location
LocationTaskCompletionSource.SetResult(location);
}
}
/// <summary>
/// Start listen to location update / gather device location.
/// </summary>
private void StartLocationUpdate()
{
InvokeOnMainThread(async() =>
{
// Don't start another location manager if there is one already running
if (FusedLocationClient == null ||
LocationManager == null)
{
var isRequestLocationSuccessful = false;
var isLastKnownLocationUseable = false;
// Check permission
if (IsPermissionGrantedImpl())
{
// Check if Google Play service is available, if it is available, then we can only use fused location service
if (IsGooglePlayLocationAvailableAndEnabled())
{
try
{
FusedLocationClient = LocationServices.GetFusedLocationProviderClient(Application.Context);
if (FusedLocationClient != null)
{
// Try get the last known location or current device location
if (!UpdateLocation(await FusedLocationClient.GetLastLocationAsync()))
{
// Then request the location update
var locationRequest = new LocationRequest()
.SetPriority(LocationRequest.PriorityHighAccuracy)
.SetInterval(5000) // Google document mention 5 seconds
.SetFastestInterval(0);
FusedLocationCallback = new LocationCallback();
FusedLocationCallback.LocationResult += FusedLocationCallback_LocationResult;
await FusedLocationClient.RequestLocationUpdatesAsync(locationRequest, FusedLocationCallback);
}
else
{
// No need to get next provider for location since we already have the location
isLastKnownLocationUseable = true;
}
isRequestLocationSuccessful = true;
}
}
catch
{
// Ignore all error including lack of permission or provider is not enabled
}
}
// In some event that Google Play service is not available or not ready, fall back to Android location instead
// Acquire a reference to the system Location Manager
if (!isLastKnownLocationUseable)
{
LocationManager = (LocationManager)Application.Context.GetSystemService(Context.LocationService);
if (LocationManager != null &&
LocationManager.AllProviders != null)
{
// Get location from all provider to increase the chances of getting a location
foreach (var provider in LocationManager.AllProviders)
{
try
{
// Try get the last known location or current device location
if (!UpdateLocation(LocationManager.GetLastKnownLocation(provider)))
{
// Then request the location update
LocationManager.RequestLocationUpdates(provider, 0, 0f, this);
isRequestLocationSuccessful = true;
}
else
{
// No need to get next provider for location since we already have the location
isRequestLocationSuccessful = true;
isLastKnownLocationUseable = true;
break;
}
}
catch
{
// Ignore all error including lack of permission or provider is not enabled
}
}
}
}
}
// Stop location service if initialized failed or we already have the location
if (!isRequestLocationSuccessful)
{
StopLocationUpdate(GeolocationStatus.SetupError);
}
else if (isLastKnownLocationUseable)
{
StopLocationUpdate(GeolocationStatus.Successful);
}
}
});
}
