public void OnLocationChanged(Location location) {
try {
_currentLocation = location;
if (_currentLocation == null)
_location = "Unable to determine your location.";
else {
_location = String.Format("{0},{1}", _currentLocation.Latitude, _currentLocation.Longitude);
Geocoder geocoder = new Geocoder(this);
//The Geocoder class retrieves a list of address from Google over the internet
IList<Address> addressList = geocoder.GetFromLocation(_currentLocation.Latitude, _currentLocation.Longitude, 10);
Address addressCurrent = addressList.FirstOrDefault();
if (addressCurrent != null) {
StringBuilder deviceAddress = new StringBuilder();
for (int i = 0; i < addressCurrent.MaxAddressLineIndex; i++)
deviceAddress.Append(addressCurrent.GetAddressLine(i))
.AppendLine(",");
_address = deviceAddress.ToString();
}
else
_address = "Unable to determine the address.";
IList<Address> source = geocoder.GetFromLocationName(_sourceAddress, 1);
Address addressOrigin = source.FirstOrDefault();
var coord1 = new LatLng(addressOrigin.Latitude, addressOrigin.Longitude);
var coord2 = new LatLng(addressCurrent.Latitude, addressCurrent.Longitude);
var distanceInRadius = Utils.HaversineDistance(coord1, coord2, Utils.DistanceUnit.Miles);
_remarks = string.Format("Your are {0} miles away from your original location.", distanceInRadius);
Intent intent = new Intent(this,typeof(GPSServiceReciever));
intent.SetAction(GPSServiceReciever.LOCATION_UPDATED);
intent.AddCategory(Intent.CategoryDefault);
intent.PutExtra("Location", _location);
intent.PutExtra("Address", _address);
intent.PutExtra("Remarks", _remarks);
SendBroadcast(intent);
}
}
catch (Exception ex){
_address = "Unable to determine the address.";
}
}
public static double HaversineDistance(LatLng coord1, LatLng coord2, DistanceUnit unit) {
double R = (unit == DistanceUnit.Miles) ? 3960 : 6371;
var lat = (coord2.Latitude - coord1.Latitude).ToRadian();
var lng = (coord2.Longitude - coord1.Longitude).ToRadian();
var h1 = Math.Sin(lat / 2) * Math.Sin(lat / 2) +
Math.Cos(coord1.Latitude.ToRadian()) * Math.Cos(coord2.Latitude.ToRadian()) *
Math.Sin(lng / 2) * Math.Sin(lng / 2);
var h2 = 2 * Math.Asin(Math.Min(1, Math.Sqrt(h1)));
return R * h2;
}
