why getSpeed() always return 0 on android

Question

I need to get the speed and heading from the gps. However the only number i have from location.getSpeed() is 0 or sometimes not available. my code:

Answer 1

On a spherical planet distance should be calculated with these formulas :

private static Double distance(Location one, Location two) {
       int R = 6371000;        
       Double dLat = toRad(two.getLatitude() - one.getLatitude());
       Double dLon = toRad(two.getLongitude() - one.getLongitude());
       Double lat1 = toRad(one.getLatitude());
       Double lat2 = toRad(two.getLatitude());         
       Double a = Math.sin(dLat / 2) * Math.sin(dLat / 2)
               + Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1) * Math.cos(lat2);        
       Double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));        
       Double d = R * c;
       return d;
   }
private static double toRad(Double d) {
       return d * Math.PI / 180;
   }

Answer 2

There is my custom LocationListener used to get speed manually and by location object if has speed.

 new LocationListener() {
        private Location mLastLocation;

        @Override
        public void onLocationChanged(Location pCurrentLocation) {
            //calcul manually speed
            double speed = 0;
            if (this.mLastLocation != null)
                speed = Math.sqrt(
                        Math.pow(pCurrentLocation.getLongitude() - mLastLocation.getLongitude(), 2)
                                + Math.pow(pCurrentLocation.getLatitude() - mLastLocation.getLatitude(), 2)
                ) / (pCurrentLocation.getTime() - this.mLastLocation.getTime());
            //if there is speed from location
            if (pCurrentLocation.hasSpeed())
                //get location speed
                speed = pCurrentLocation.getSpeed();
            this.mLastLocation = pCurrentLocation;
            ////////////
            //DO WHAT YOU WANT WITH speed VARIABLE
            ////////////
        }

        @Override
        public void onStatusChanged(String s, int i, Bundle bundle) {

        }

        @Override
        public void onProviderEnabled(String s) {

        }

        @Override
        public void onProviderDisabled(String s) {

        }
    };

Answer 3

getspeed() works fine. You don't have to do the math using distance formula. It is already there in getspeed, As long as there are latitude and longitude, there will be a speed in getspeed.

Answer 4

getSpeed() method actually works fine but you have to use a high request interval like 1 second and you need high accuracy, first i was doing 3 second interval and PRIORITY_BALANCED_POWER_ACCURACY and i kept getting 0 values until i change it like i say. I am using fused location provider api.

public class Main3Activity extends AppCompatActivity {

private FusedLocationProviderClient mFusedLocationClient;
private int speed;
private double lat;
private double lng;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);

    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
}

@Override
protected void onResume() {
    super.onResume();
    if(!runtime_permissions()) {
        requestLocations();
    }
}

@Override
protected void onPause() {
    super.onPause();
    //stop location updates when Activity is no longer active
    if (mFusedLocationClient != null) {
        mFusedLocationClient.removeLocationUpdates(mLocationCallback);
    }
}

@SuppressLint("MissingPermission")
private void requestLocations(){
    LocationRequest mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(1000);;
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

    mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
}

LocationCallback mLocationCallback = new LocationCallback() {
    @Override
    public void onLocationResult(LocationResult locationResult) {
        List<Location> locationList = locationResult.getLocations();
        if (locationList.size() > 0) {
            //The last location in the list is the newest
            Location location = locationList.get(locationList.size() - 1);

            lat = location.getLatitude();
            lng = location.getLongitude();

            //speed in km/h
            speed = (int) ((location.getSpeed() * 3600) / 1000);

        }
    }
};

private boolean runtime_permissions() {
    if(Build.VERSION.SDK_INT >= 23 && ContextCompat.checkSelfPermission(this,
            Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED){

        requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION},100);

        return true;
    }
    return false;
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(requestCode == 100){
        if( grantResults[0] == PackageManager.PERMISSION_GRANTED){
            onResume();
        }else{
            runtime_permissions();
        }
    }
}

}

Answer 5

Based on other suggestions here I put together this code with comments to why:

public static float getSpeedKmh(Location newLocation, Location previousLocation)
{
    if(newLocation == null) throw new IllegalArgumentException("newLocation must not be null");
    float speed = -1.0f;
    if(newLocation.hasSpeed()) /* gps doppler speed at the current moment preferred */
    {
        speed = newLocation.getSpeed();
    }else /* may be wifi or celltower based location: compute AVERAGE speed since last fix */
    {
       if(previousLocation == null) throw new IllegalArgumentException("Cannot compute speed without previousLocation (was null)");
       if(previousLocation.getTime()==newLocation.getTime())
           throw new IllegalArgumentException("Cannot compute speed from same time locations!"); /* diff by zero protection */
       speed = newLocation.distanceTo(previousLocation) * 1000.0f /* time diff in millis so multiply by 1000 */
           / Math.abs(newLocation.getTime() - previousLocation.getTime()); /* Math abs: so you can even swap new and older location without effect */
    }
       return speed * 3.6f; /* m/s -> km/h */
}

Answer 6

location.getSpeed() only returns what was set with location.setSpeed(). This is a value that you can set for a location object.

To calculate the speed using GPS, you'll have to do a little math:

Speed = distance / time

So you would need to do:

(currentGPSPoint - lastGPSPoint) / (time between GPS points)

All converted to ft/sec, or however you want to show the speed. This is how I did it when I made a runner app.

More specifically, you'll need to calculate for absolute distances:

(sqrt((currentGPSPointX - lastGPSPointX)^2) + (currentGPSPointY - lastGPSPointY)^2)) / (time between GPS points)

It might help to make a new TrackPoint class or something, which keeps the GPS location and time it was taken inside.