getLastKnownLocation returning null in Android

Question

I know this has been talked about many times but nothing has helped me fix the problem that getLastKnownLocation is returning null.

My Activity implement LocationListener:

public class MainActivity extends Activity implements
    GooglePlayServicesClient.ConnectionCallbacks,
    GooglePlayServicesClient.OnConnectionFailedListener, LocationListener {

I have this in my onCreate method:

  LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE);
  lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);

And i then try to get the user location like so (also in onCreate):

    // Getting the Co-ordinates of the users current location
    Location location = lm
            .getLastKnownLocation(LocationManager.GPS_PROVIDER);

    if(location != null){
        longitude = location.getLongitude();
        latitude = location.getLatitude();
    }

I tried then:

@Override
public void onLocationChanged(Location location) {      
    longitude = location.getLongitude();
    latitude = location.getLatitude();
}

Am I missing something?

EDIT: Still not working but code I have tried:

    if (lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
    while (location == null) {
        if (counter > MAX_TIME) {   
        }
        else {
            try {
                 location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            counter += 1000;
        }
    }
    }

Ajay S · Answer 1 · 2014-03-10T14:45:20.403

1

You have to wait for a while to get the location because GPS take some seconds to warm up.

If you call directly getLastLocation it will return you last find location or sometime null when there is no cache location. It always good if you implement a location service and try to get the location of onLocationChanged. You can keep this variable as static to access in other classes.

Sometime, GPS provider fail to get location when you are in building so in that case you can switch to Network provider to get the location but in Network provider accurary would be less as comparision to GPS provider

For more accurate location, you can use a while in onLocationChanged until you think accuracy is better.

edited Mar 10 '14 at 14:45

answered Mar 10 '14 at 14:39

Ajay S

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Best to implement a loop here that checks every second or so to see if the location is no longer null, obviously with a time limit (say 30 seconds). – confused_at_times Mar 10 '14 at 14:42
@confused_at_times have u an example of the loop please? – Natalie Carr Mar 10 '14 at 14:47
@NatalieCarr Did you make any location service ? – Ajay S Mar 10 '14 at 14:47
@TGMCians No I don't think so, pretty new to android – Natalie Carr Mar 10 '14 at 14:52
1

@NatalieCarr See this http://stackoverflow.com/questions/1513485/how-do-i-get-the-current-gps-location-programmatically-in-android?rq=1 – Ajay S Mar 10 '14 at 14:54

confused_at_times · Accepted Answer · 2014-03-10T16:02:56.877

1

From documentation:

"Returns a Location indicating the data from the last known location fix obtained from the given provider.

Returns the last known location for the provider, or null "

So, there must be at least one previous location obtained using the supplied provider. For it to receive a location, you have to register for updates at least once using that provider and receive an actual update. After which, getLastKnownLocation will return that value. If you want to register for locations provided by other apps, use Location.PASSIVE_PROVIDER.

Hope this helps.

Edit: As I commented above, put a while loop in that iterates say for 30 seconds and checks every second if the location is not longer null. You need this to happen at least once, to then be able to use getLastKnownLocation, AFAIK.

Edit with small, untested example. Best to put all this in an AsyncTask too i.e. in doInBackground. Note, I'm assuming you are storing the Location object itself, rather than separating it out into longitude and latitude.:

if (lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
    long final MAX_TIME = 30000;
    long counter = 0;
    while (location == null) {
        if (counter > MAX_TIME) {
            return False;
        }
        Thread.sleep(1000);
        counter += 1000;
    }
} else {
    return False;
}

Edit: Remember, Location is updated in onLocationUpdate(Location location). One this has updated, you then have a location object not equal to null.

edited Mar 10 '14 at 16:02

answered Mar 10 '14 at 14:41

confused_at_times

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Unfortunately it just times out and location remains at null – Natalie Carr Mar 10 '14 at 15:24
Make sure the location provider is enabled first.. I've updated the post. – confused_at_times Mar 10 '14 at 15:29
Also, ensure you have correct manifest permissions (FINE_LOCATION). – confused_at_times Mar 10 '14 at 15:32
I haven edited my post to show code, still timing out – Natalie Carr Mar 10 '14 at 15:50
No, the loop is there just until Location is no longer null. Remove the getLastKnownLocation from it. If the loop times out then you have a problem elsewhere getting a location. Rather than use GPS, try with NETWORK_PROVIDER as you are more likely to get a location indoors with it. – confused_at_times Mar 10 '14 at 16:01
I am trying with both atm, dont know why it is remaining at null, will try delve further! Thank you – Natalie Carr Mar 10 '14 at 16:40
Yes I have fine and course location as I use the google maps and it picks up the location setting `.setMyLocationEnabled(true)` – Natalie Carr Mar 10 '14 at 16:49
Ok, last thing that comes to mind is the phone settings. Have you given apps permission to use your phone's location in Settings->Location. There are two options: Wifi and GPS? If that isn't it, I'm stumped! – confused_at_times Mar 10 '14 at 18:40

getLastKnownLocation returning null in Android

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