Develop Reference

Android: GPS Location not working

I am trying to retrieve Location as follows:
LocationManager locationManager = (LocationManager)MyApp.getAppContext().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
// Getting the name of the provider that meets the criteria
String provider = locationManager.getBestProvider(criteria, false);
if(provider!=null && !provider.equals("")){
// NOTE: the location below is null !!
Location location = locationManager.getLastKnownLocation(provider);
String lat = location.getLatitude();
String lng = location.getLongitude();
}
The 'location' above is null. Why?
But when i open the (Google) Maps app - it shows location correctly, and even a notification icon (looks like a exclamation mark) shows up.
And there is a GPS Coordinates app - which also shows up blank.
I have turned on Settings > 'Location' on the phone. If it matters this is Android 4.4.4 Sony Experia phone.

Well, it seems that you're not checking properly if the GPS is working or not. The way you should do it:
final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
if (!manager.isProviderEnabled( LocationManager.GPS_PROVIDER ) ) {
//GPS is not enabled !!
}
You can also create an AlertDialog so the user is aware that the GPS is not enabled and you can send him to the GPS settings by doing this:
startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
After this, I'd implement a location listener and get coordinates, here is an example, check it out
How do I get the current GPS location programmatically in Android?
UPDATE: They might be getting coordinates through other provider (usually the one which is working better at that moment). So if the GPS it not working, just try other provider, here is an example:
Location lastKnownLocation = null;
List<String> providers = null;
if(locationManager != null) providers = locationManager.getAllProviders();
if(providers != null)
{
for(int i=0; i<providers.size(); i++)
{
if(locationManager != null) lastKnownLocation = locationManager.getLastKnownLocation(providers.get(i));
if(lastKnownLocation != null)
{
position = new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude());
break;
}
}
}

Trying to get latitude and latitude with Network provider

I am trying to get my current coordinates with network provider and not gps provider.
I was able to figure out the solution for that but I am a bit confused with the concept in this scenario.
Working Code
Here's my code for getting my coordinates:
public void getLocation(){
locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
if(appUtils.isOnline()){
try{
Geocoder geocoder = new Geocoder(
MainActivity.this.getApplicationContext(),
Locale.getDefault());
Location locationNetwork = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
List<Address> list;
if(locationNetwork!=null){
Toast.makeText(context,"Network Available!!",Toast.LENGTH_LONG).show();
list = geocoder.getFromLocation(locationNetwork.getLatitude(),locationNetwork.getLongitude(),3);
if(list!=null&&list.size()>0){
latitude = list.get(0).getLatitude();
longitude = list.get(0).getLongitude();
Toast.makeText(context,String.valueOf(latitude) + " (....) " + String.valueOf(longitude),Toast.LENGTH_LONG).show();
int count = 0;
while (latitude==null||longitude==null){
latitude = list.get(count).getLatitude();
longitude = list.get(count).getLongitude();
count++;
Toast.makeText(context,String.valueOf(latitude) + " --- " + String.valueOf(longitude),Toast.LENGTH_LONG).show();
}
}
}else{
Toast.makeText(context,"No response!!",Toast.LENGTH_LONG).show();
}
}catch (IOException e){
e.printStackTrace();
}
}else{
Toast.makeText(context,"Server not responding",Toast.LENGTH_LONG).show();
}
}
This piece of code is working perfectly fine when the gps is enabled. If gps is disabled, it doesn't work.
Now, if we are setting the location to NETWORK_PROVIDER:
Location locationNetwork = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
Why do we still require gps ?
Now if I change it to PASSIVE PROVIDER:
Location locationNetwork = locationManager
.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
It works fine with the passive provider. Why is it that ?
Can someone explain what is the major difference here and what would be the right way to get the coordinates with network provider ?
I know this question is been asked several times and I did went through it. I just want to get cleared with this concept.
Thank's in advance.. :)

It doesn't require GPS to use the network provider, I've done it many times. However, getLastKnowLocation may not return a value if either it has never had an app request updates for that provider, or if the last time that happened was too long ago. You cannot count on that function always returning non-NULL. If you want to ensure that you get a location, use requestSingleUpdate instead. This will always get you a location (assuming the provider you use is enabled), but may take some time- a result may not be immediately available.
(There is one other time that function may never return- if you use the GPS provider and it can't get a lock on enough sattelites to find a location. Such as if you're in an underground parking garage).

This is the bit of code that I use to quickly get the current location, by checking all available network options.
private double[] getGPS(){
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
List<String> providers = lm.getProviders(true);
/* Loop over the array backwards, and if you get an accurate location, then break out the loop*/
Location l = null;
for (int i=providers.size()-1; i>=0; i--) {
l = lm.getLastKnownLocation(providers.get(i));
if (l != null) break;
}
double[] gps = new double[2];
if (l != null) {
gps[0] = l.getLatitude();
gps[1] = l.getLongitude();
}
return gps;
}

Location mapping not returning on different devices

I have this code for getting the long and lat coordinates.
String bestProvider;
LocationManager lm = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
bestProvider = lm.getBestProvider(criteria, true);
Location location = lm.getLastKnownLocation(bestProvider);
if (location == null){
}else{
geocoder = new Geocoder(this);
try {
setLat((double)location.getLatitude());
setLng((double)location.getLongitude());
}catch (Exception e) {
e.printStackTrace();
}
}
I tried using different devices. Some returns a value for lat and long. Some do not. All devices were connected to the internet and gps enabled. Do you guys have any idea on what is causing this? Thanks!

It is due to getLastKnownLocation which may or may not exists. I suggest you to request single location update. Also remember that lastknownlocation is not necessarily accurate one it may belong to 2 days before.
dev guide:
http://developer.android.com/reference/android/location/LocationManager.html
A guide about single update
http://androidexperinz.wordpress.com/2012/04/19/current-location-update/

If there is no previous captured location, then getlastknown location does not return any value.So you need to implement the location listener to capture the location.

How to get the coarse location using Wifi or GSM or GPS, whichever is available?

My app only needs a coarse location service when started up.
In detail, I need the app's rough location so as to provide the users with the shop info nearby.
The location does NOT need to be updated constantly. In addition, coarse localization will be sufficient in this case.
I wish the app to choose GSM, or wifi, or GPS automatically, whichever is available.
The location service should also be one-time to save phone energy.
How may I do that?
I have tried using GPS separately.
My problem is I don't know how to stop the constantly-refreshing-location feature of GPS. I don't know how to make the phone select one out of the three methods, either.
Some sample codes or ideas are greatly appreciated.

Here's a certain point of view:
private void _getLocation() {
// Get the location manager
LocationManager locationManager = (LocationManager)
getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(bestProvider);
try {
lat = location.getLatitude();
lon = location.getLongitude();
} catch (NullPointerException e) {
lat = -1.0;
lon = -1.0;
}
}
This might however request a FINE_LOCATION access. So:
Another way is to use this which uses the LocationManager.
The quickest possible way is to use the Last Known location with this, I used it and it's quite fast:
private double[] getGPS() {
LocationManager lm = (LocationManager) getSystemService(
Context.LOCATION_SERVICE);
List<String> providers = lm.getProviders(true);
Location l = null;
for (int i=providers.size()-1; i>=0; i--) {
l = lm.getLastKnownLocation(providers.get(i));
if (l != null) break;
}
double[] gps = new double[2];
if (l != null) {
gps[0] = l.getLatitude();
gps[1] = l.getLongitude();
}
return gps;
}

you can use LocationClient it provides a unified/simplified (Fused) location API, check out this Video for introductory material and background or this developer guide
the main drawback is that you make you app dependent on the existence of Google Play Services on the device.

In order to get info from specific provider you should use: LocationManager.getLastKnownLocation(String provider), if you want your app to choose automatically between providers then you can add choosing of the provider with getBestProvider method. As for stopping refreshing of GPS location, I didn't quite catch. Do you need to get the location info only once or do you need to monitor location changes periodically?
EDIT: Oh by the way, if you want your location info to be up-to-date you should use requestSingleUpdate method of location manager, with specified Criteria. In this case provider should also be chosen automatically

Android Runtime GPS Location - Blackberry Device - not working

My app has been ported from Android to blackberry and it works fine...
the only thing not working is the GPS location which works on the android....
the app displays a message to the using that we are trying to find the location and if no location is found we tell the user that we could not retrieve a location..
here is the code
private void gpsLocation()
{
//Get the location manager
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
//Provide Criteria
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
locationManager.requestLocationUpdates(provider, 400, 1, this);
if(location != null){
onLocationChanged(location);
} else{
Log.i(TAG, "no GPS location available - waiting for GPS fix");
Toast.makeText(getApplicationContext(), R.string.gpsWaitingToast, Toast.LENGTH_SHORT).show();
if (Debug.GPS_USE_MONTREAL) {
currentLatitude = Double.valueOf(Debug.GPS_LAT_MONTREAL); currentLongitude = Double.valueOf(Debug.GPS_LNG_MONTREAL); // montreal
}
waitForGpsFix(GPSFIX_DELAY);
}
its not working,, I restarted the app ,, did it next to a window and all that stuff..
nothing works..
your advise and help is greatly appreciated.
Regards

There was previously a bug where LocationManager.NETWORK_PROVIDER returned null, which may still be returned by the locationManager.getBestProvider() method. This should be fixed in the newer OS builds, however.
If you'd like to fix your code immediately, all you would need to do would be to set:
provider = LocationManager.GPS_PROVIDER
as in the early stages, GPS_PROVIDER was the only provider that was implemented in the player.