Retrieving # of satellites used in gps fix from Android
I am trying to retrieve the # of satellites used in the GPS fix. I have implemented two different methods, as shown below:
package ti.utils;
import android.app.Activity;
import android.content.Context;
import android.location.GpsSatellite;
import android.location.GpsStatus;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
public class Gps {
private static final int TWO_MINUTES = 1000 * 60 * 2;
private static Location Location;
public static int Satellites = -1;
public static void StartTracking(Activity activity)
{
final LocationManager locationManager = (LocationManager) activity.getSystemService(Context.LOCATION_SERVICE);
//listen for gps status changes.
GpsStatus.Listener gpsStatusListener = new GpsStatus.Listener() {
public void onGpsStatusChanged(int event) {
Log("In onGpsStatusChanged event: " + event);
if (event == GpsStatus.GPS_EVENT_SATELLITE_STATUS || event == GpsStatus.GPS_EVENT_FIRST_FIX) {
GpsStatus status = locationManager.getGpsStatus(null);
Iterable<GpsSatellite> sats = status.getSatellites();
// Check number of satellites in list to determine fix state
Satellites = 0;
for (GpsSatellite sat : sats) {
//if(sat.usedInFix())
Satellites++;
}
Log("Setting Satellites from GpsStatusListener: " + Satellites);
}
}
};
locationManager.addGpsStatusListener(gpsStatusListener);
//listen for location changes.
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
// Called when a new location is found by the network location provider.
try
{
Log("Location changed! Speed = " + location.getSpeed() + " & Satellites = " + location.getExtras().getInt("satellites"));
boolean isBetter = isBetterLocation(location, Location);
if(isBetter)
{
Log("Set to new location");
Location = location;
Satellites = location.getExtras().getInt("satellites");
Log("Setting Satellites from LocationListener: " + Satellites);
}
}
catch(Exception exc)
{
Log(exc.getMessage());
}
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
}
/** Determines whether one Location reading is better than the current Location fix
* @param location The new Location that you want to evaluate
* @param currentBestLocation The current Location fix, to which you want to compare the new one
*/
protected static boolean isBetterLocation(Location location, Location currentBestLocation) {
if (currentBestLocation == null) {
// A new location is always better than no location
return true;
}
// Check whether the new location fix is newer or older
long timeDelta = location.getTime() - currentBestLocation.getTime();
boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
boolean isNewer = timeDelta > 0;
// If it's been more than two minutes since the current location, use the new location
// because the user has likely moved
if (isSignificantlyNewer) {
return true;
// If the new location is more than two minutes older, it must be worse
} else if (isSignificantlyOlder) {
return false;
}
// Check whether the new location fix is more or less accurate
int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
boolean isLessAccurate = accuracyDelta > 0;
boolean isMoreAccurate = accuracyDelta < 0;
boolean isSignificantlyLessAccurate = accuracyDelta > 200;
// Check if the old and new location are from the same provider
boolean isFromSameProvider = isSameProvider(location.getProvider(),
currentBestLocation.getProvider());
// Determine location quality using a combination of timeliness and accuracy
if (isMoreAccurate) {
return true;
} else if (isNewer && !isLessAccurate) {
return true;
} else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
return true;
}
return false;
}
/** Checks whether two providers are the same */
private static boolean isSameProvider(String provider1, String provider2) {
if (provider1 == null) {
return provider2 == null;
}
return provider1.equals(provider2);
}
private static void Log(String message) {
if(message != null && message.length() > 0) {
//android.util.Log.i(LCAT, message);
org.appcelerator.kroll.common.Log.i("SygicModule", message);
}
}
}
Neither of the listener events (onGpsStatusChanged & onLocationChanged) ever fire, even though I have standalone GPS enabled on my phone. I have the ACCESS_FINE_LOCATION permission set:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
I downloaded a 3rd party app called GPS Status and it was able to correctly display the # of satellites, so I know it isn't an issue with my Droid X2.
Any ideas?
Answer
Here is the code that ended up working.
package ti.utils;
import android.app.Activity;
import android.content.Context;
import android.location.GpsSatellite;
import android.location.GpsStatus;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
public class Gps {
private static final int TWO_MINUTES = 1000 * 60 * 2;
private static Location Location;
public static int Satellites = -1;
public static void StartTracking(Activity activity)
{
final LocationManager locationManager = (LocationManager) activity.getSystemService(Context.LOCATION_SERVICE);
//listen for gps status changes.
GpsStatus.Listener gpsStatusListener = new GpsStatus.Listener() {
@Override
public void onGpsStatusChanged(int event) {
Log("In onGpsStatusChanged event: " + event);
if (event == GpsStatus.GPS_EVENT_SATELLITE_STATUS || event == GpsStatus.GPS_EVENT_FIRST_FIX) {
GpsStatus status = locationManager.getGpsStatus(null);
Iterable<GpsSatellite> sats = status.getSatellites();
// Check number of satellites in list to determine fix state
Satellites = 0;
for (GpsSatellite sat : sats) {
//if(sat.usedInFix())
Satellites++;
}
Log("Setting Satellites from GpsStatusListener: " + Satellites);
}
}
};
locationManager.addGpsStatusListener(gpsStatusListener);
//listen for location changes.
LocationListener locationListener = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
// Called when a new location is found by the network location provider.
/*try
{
Log("Location changed! Speed = " + location.getSpeed() + " & Satellites = " + location.getExtras().getInt("satellites"));
boolean isBetter = isBetterLocation(location, Location);
if(isBetter)
{
Log("Set to new location");
Location = location;
Satellites = location.getExtras().getInt("satellites");
Log("Setting Satellites from LocationListener: " + Satellites);
}
}
catch(Exception exc)
{
Log(exc.getMessage());
}*/
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
/** Determines whether one Location reading is better than the current Location fix
* @param location The new Location that you want to evaluate
* @param currentBestLocation The current Location fix, to which you want to compare the new one
*/
protected static boolean isBetterLocation(Location location, Location currentBestLocation) {
if (currentBestLocation == null) {
// A new location is always better than no location
return true;
}
// Check whether the new location fix is newer or older
long timeDelta = location.getTime() - currentBestLocation.getTime();
boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
boolean isNewer = timeDelta > 0;
// If it's been more than two minutes since the current location, use the new location
// because the user has likely moved
if (isSignificantlyNewer) {
return true;
// If the new location is more than two minutes older, it must be worse
} else if (isSignificantlyOlder) {
return false;
}
// Check whether the new location fix is more or less accurate
int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
boolean isLessAccurate = accuracyDelta > 0;
boolean isMoreAccurate = accuracyDelta < 0;
boolean isSignificantlyLessAccurate = accuracyDelta > 200;
// Check if the old and new location are from the same provider
boolean isFromSameProvider = isSameProvider(location.getProvider(),
currentBestLocation.getProvider());
// Determine location quality using a combination of timeliness and accuracy
if (isMoreAccurate) {
return true;
} else if (isNewer && !isLessAccurate) {
return true;
} else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
return true;
}
return false;
}
/** Checks whether two providers are the same */
private static boolean isSameProvider(String provider1, String provider2) {
if (provider1 == null) {
return provider2 == null;
}
return provider1.equals(provider2);
}
private static void Log(String message) {
if(message != null && message.length() > 0) {
//android.util.Log.i(LCAT, message);
org.appcelerator.kroll.common.Log.i("UtilsModule", message);
}
}
}