Current location, Latitude and Longitude

Question

My problem is getting latitude and longitude.

In emulator I use: Lat - 54.035795, Long - 21.760029. But when I call getLatitude() or getLongitude() I get 54.0 and 21.0.
So I can't get accurate distance between two points. What is the problem?

Please help me.

public final class LocationGpsListener implements LocationListener 
{

        private final Context mContext;
        public boolean isGPSEnabled = false;
        boolean isNetworkEnabled = false;
        boolean canGetLocation = false;

        Location location;
        Double latitude;
        Double longitude;

        private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
        private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1;

        protected LocationManager locationManager;

        public LocationGpsListener(Context context) {
            this.mContext = context;
            getLocation();
        }

        public Location getLocation() {
            try {
                locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
                isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
                Log.v("isGPSEnabled", "=" + isGPSEnabled);

                isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
                Log.v("isNetworkEnabled", "=" + isNetworkEnabled);

                if (isGPSEnabled == false && isNetworkEnabled == false) {

                } else {
                    this.canGetLocation = true;
                    if (isNetworkEnabled) {
                        locationManager.requestLocationUpdates(
                                LocationManager.NETWORK_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        if (locationManager != null) {
                            location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                            if (location != null) {
                                latitude = location.getLatitude();
                                longitude = location.getLongitude();
                            }
                        }
                    }
                    if (isGPSEnabled) {
                        if (location == null) {
                            locationManager.requestLocationUpdates(
                                    LocationManager.GPS_PROVIDER,
                                    MIN_TIME_BW_UPDATES,
                                    MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                            Log.d("GPS Enabled", "GPS Enabled");
                            if (locationManager != null) {
                                location = locationManager
                                        .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                                if (location != null) {
                                    latitude = location.getLatitude();
                                    longitude = location.getLongitude();
                                }
                            }
                        }
                    }
                }

            } catch (Exception e) {
                e.printStackTrace();
            }

            return location;
        }

        public void stopUsingGPS() {
            if (locationManager != null) {
                locationManager.removeUpdates(LocationGpsListener.this);
            }
        }

        public double getLatitude() {
            if (location != null) {
                latitude = location.getLatitude();
            }
            return latitude;
        }

        public double getLongitude() {
            if (location != null) {
                longitude = location.getLongitude();
            }
            return longitude;
        }

        public boolean canGetLocation() {
            return this.canGetLocation;
        }

        public void showSettingsAlert() {
            AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

            alertDialog.setTitle("GPS");
            alertDialog.setMessage("GPS is ENABLED:");

            alertDialog.setPositiveButton("Settings",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            Intent intent = new Intent(
                                    Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                            mContext.startActivity(intent);
                        }
                    });

            alertDialog.setNegativeButton("Cancel",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            dialog.cancel();
                        }
                    });
            alertDialog.show();
        }

        @Override
        public void onLocationChanged(Location location) {
        }

        @Override
        public void onProviderDisabled(String provider) {
        }

        @Override
        public void onProviderEnabled(String provider) {
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
        }

}

And i use:

mGPS = new LocationGpsListener(this);

if(mGPS.canGetLocation ){

    longitude = mGPS.getLatitude();
    latitude = mGPS.getLongitude();         
}else{
     longitude = 21.230000;
     latitude = 53.230000;
}

Location l1 = new Location("lok a");
l1.setLatitude(latitude);
l1.setLongitude(longitude);

Location l2 = new Location("lok b");
l2.setLatitude(54.035679);
l2.setLongitude(21.784879);                             

Answer 1

I cannot reproduce your issue, however I can supply you with an improved version of your code:

import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;

public final class LocationGpsListener implements LocationListener {

    public boolean isGPSEnabled = false;

    private Location location;

    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1;

    protected LocationManager locationManager;

    public LocationGpsListener(Context context) {
        locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
        // TODO check is network/gps is enabled and display the system settings
        // see
        // https://github.com/unchiujar/Umbra/blob/master/src/main/java/org/unchiujar/umbra/activities/FogOfExplore.java#L599
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
                MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES,
                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

        location = new Location("fake");
        location.setLatitude(0);
        location.setLongitude(0);
    }

    public void stopLocationUpdates() {
        if (locationManager != null) {
            locationManager.removeUpdates(LocationGpsListener.this);
        }
    }

    public double getLatitude() {
        return location.getLatitude();
    }

    public double getLongitude() {
        return location.getLongitude();
    }

    @Override
    public void onLocationChanged(Location location) {
        this.location = location;
    }

    @Override
    public void onProviderDisabled(String provider) {
        // NO-OP
    }

    @Override
    public void onProviderEnabled(String provider) {
        // NO-OP
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // NO-OP
    }

}

The code you posted does not use the listener pattern correctly (mine doesn't either but it's an improvement). The location logic should be in the onLocationChanged method not in a random method somewhere else. In

I recommend you read: http://www.vogella.com/articles/AndroidLocationAPI/article.html

Also, never use catch(Exception e) it will lead to all sort of awfully hard to trace bugs. Why is the Catch(Exception) almost always a bad Idea? http://today.java.net/article/2006/04/04/exception-handling-antipatterns#catchingException

Answer 2

I think the problem is that you're not being specific enough with the location provider used, and you're getting back course accuracy.

Get the best location provider using Criteria to set the desired accuracy:

locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_HIGH);  
locationManager.getBestProvider(criteria, true);

or perhaps alternatively use the override of requestLocationUpdates that takes Criteria as a parameter.

Check the above, and also have "android.permission.ACCESS_FINE_LOCATION" in your manifest.

Answer 3

My problem was in getting Location befor my GPS set good value

And I had one funny problem (when app crashed): "Remember, check whether the device has a GPS " :)