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How do I get the current GPS location programmatically in Android?

Asked 12 years ago
Viewed 995.36 k times

I need to get my current location using GPS programmatically. How can i achieve it?

asked 12 years ago

Correct Answer

I have created a small application with step by step description to get current location's GPS coordinates.

Complete example source code is in Get Current Location coordinates , City name - in Android.


See how it works:

  • All we need to do is add this permission in the manifest file:

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    
  • And create a LocationManager instance like this:

    LocationManager locationManager = (LocationManager)
    getSystemService(Context.LOCATION_SERVICE);
    
  • Check if GPS is enabled or not.

  • And then implement LocationListener and get coordinates:

    LocationListener locationListener = new MyLocationListener();
    locationManager.requestLocationUpdates(
    LocationManager.GPS_PROVIDER, 5000, 10, locationListener);
    
  • Here is the sample code to do so


/*---------- Listener class to get coordinates ------------- */
private class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location loc) {
        editLocation.setText("");
        pb.setVisibility(View.INVISIBLE);
        Toast.makeText(
                getBaseContext(),
                "Location changed: Lat: " + loc.getLatitude() + " Lng: "
                    + loc.getLongitude(), Toast.LENGTH_SHORT).show();
        String longitude = "Longitude: " + loc.getLongitude();
        Log.v(TAG, longitude);
        String latitude = "Latitude: " + loc.getLatitude();
        Log.v(TAG, latitude);

        /*------- To get city name from coordinates -------- */
        String cityName = null;
        Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault());
        List<Address> addresses;
        try {
            addresses = gcd.getFromLocation(loc.getLatitude(),
                    loc.getLongitude(), 1);
            if (addresses.size() > 0) {
                System.out.println(addresses.get(0).getLocality());
                cityName = addresses.get(0).getLocality();
            }
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        String s = longitude + "\n" + latitude + "\n\nMy Current City is: "
            + cityName;
        editLocation.setText(s);
    }

    @Override
    public void onProviderDisabled(String provider) {}

    @Override
    public void onProviderEnabled(String provider) {}

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

answered 6 years ago

Other Answer

Here is additional information for other answers.

Since Android has

GPS_PROVIDER and NETWORK_PROVIDER

you can register to both and start fetch events from onLocationChanged(Location location) from two at the same time. So far so good. Now the question do we need two results or we should take the best. As I know GPS_PROVIDER results have better accuracy than NETWORK_PROVIDER.

Let's define Location field:

private Location currentBestLocation = null;

Before we start listen on Location change we will implement the following method. This method returns the last known location, between the GPS and the network one. For this method newer is best.

/**
 * @return the last know best location
 */
private Location getLastBestLocation() {
    Location locationGPS = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
    Location locationNet = mLocationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

    long GPSLocationTime = 0;
    if (null != locationGPS) { GPSLocationTime = locationGPS.getTime(); }

    long NetLocationTime = 0;

    if (null != locationNet) {
        NetLocationTime = locationNet.getTime();
    }

    if ( 0 < GPSLocationTime - NetLocationTime ) {
        return locationGPS;
    }
    else {
        return locationNet;
    }
}

Each time when we retrieve a new location we will compare it with our previous result.

...
static final int TWO_MINUTES = 1000 * 60 * 2;
...

I add a new method to onLocationChanged:

@Override
public void onLocationChanged(Location location) {

    makeUseOfNewLocation(location);

    if(currentBestLocation == null){
        currentBestLocation = location;
    }

    ....
}


/**
 * This method modify the last know good location according to the arguments.
 *
 * @param location The possible new location.
 */
void makeUseOfNewLocation(Location location) {
    if ( isBetterLocation(location, currentBestLocation) ) {
        currentBestLocation = location;
    }
}

....

/** 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 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 boolean isSameProvider(String provider1, String provider2) {
    if (provider1 == null) {
        return provider2 == null;
    }
    return provider1.equals(provider2);
}

....
answered 12 years ago