Android LocationManager.getLastKnownLocation() returns null

Question

So I'm trying to sample the gps coordinates just once in an application. I don't want to create a LocationListener object to constantly get gps updates. I want to wait until receiving the coordinates, and then proceed on to another task.

Here is a code snippet

LocationManager lm = (LocationManager)act.getSystemService(Context.LOCATION_SERVICE);
Criteria crit = new Criteria();
crit.setAccuracy(Criteria.ACCURACY_FINE);
String provider = lm.getBestProvider(crit, true);
Location loc = lm.getLastKnownLocation(provider);

The loc variable is always null in the emulator. I tried using the command "geo fix latitude longitude" to set it, and also I tried using the DDMS way of setting it. Neither method had any effect on the code. Also the snippet isn't causing any exceptions.

Thanks for your help.

Answer 1

Try using the MyLocationOverlay , create a runnable that does what you need to do with that GPS location, and pass it to

boolean     runOnFirstFix(java.lang.Runnable runnable)
          Queues a runnable to be executed as soon as we have a location fix.

and then disable the location updates for the MyLocationOverlay.

Edit: The reason the location is null is because at the time that code is run, no geofix has been received.

Answer 2

The call to request update for a location is not blocking, hence it wont wait there. Also the provider in emulator may not have been started.

A possible check could be to see if the settings in it disable gps provider ? then send geo fix.

However, I would use Location Listener, it would be ideal in your case since you need a geo fix to proceed further.Location Listener is Used for receiving notifications from the LocationManager when the location has changed. You can unregister the listener after first geofix.

Note: It can take some time on device to get current location, and even on device this can return null.

Answer 3

Here's a nice example with source code http://marakana.com/forums/android/android_examples/42.html