location manager android problem

Question

I am trying to get a user's location when a button is clicked.
I have the following code in my button onclick listener:


locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
bestProvider = locationManager.getBestProvider(criteria, false);
Location currentLocation = locationManager.getLastKnownLocation(bestProvider);
Log.e(tag,"reached till here");
location = Double.toString(currentLocation.getLatitude()) + " " + Double.toString(currentLocation.getLongitude());
Toast.makeText(getApplicationContext(), location, Toast.LENGTH_LONG);
MyLocation.setText(location);

I am getting the the output reached till here in logcat. After that the application stops and asks me to force close it. I initially did some searching and found out that getLatitude and getLongitude return double values. So I corrected the code. But still I am getting an error. What am I doing wrong?

EDIT : The logcat error:
Got RemoteException sending setActive(false) notification to pid 796 uid 10036
I think currentLocation is returning null

can you debug and see if your object "currentLocation" is null? and also, what is the error you get in the logcat? — Finuka, Aug 01 '11 at 15:32
Please show us the log. It might be that there is no last known location. Then you will get null instead. — TofferJ, Aug 01 '11 at 15:33

Ovidiu Latcu · Accepted Answer · 2011-08-01T15:45:12.290

3

If your are testing your app in the Emulator you probably don't have any provider and the currentLocation object is null and that is why getLatitude() and getLongitude() will give a NPE.

Edit: as the @grinnner said, from the DDMS perspective you can simulate the sending of location coordinates. Open the DDMS Perspective in eclipse and in the LocationControls tab set the Longitude and Latitude and then click send. Be sure that the focus in the Devices tab is on the emulator that you are running your app on.

edited Aug 01 '11 at 15:45

answered Aug 01 '11 at 15:40

Ovidiu Latcu

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He can spoof the location from the DDMS perspective if he uses Eclipse. – thegrinner Aug 01 '11 at 15:43
Could you tell me how to get a provider if I am using an emulator? – Brahadeesh Aug 01 '11 at 15:47
@thegrinner I dont know how to do that. Can you explain the steps please? – Brahadeesh Aug 01 '11 at 15:47
I just have one virtual device. so shouldnt be a problem. I'll try and let you know soon – Brahadeesh Aug 01 '11 at 15:52
I tried doing that. But I am still getting an error. Any idea when should I send the location parameters? I have the code above in a button onclick listener onClick method. I tried sending before and after I click the button. To no avail. – Brahadeesh Aug 01 '11 at 15:57

score 1 · Answer 2 · answered Aug 01 '11 at 15:42

If you don't have a last known location (just do a simple null check for the value returned), then you need to add a location listener to get a location. Something like this:

// Start listening for a new location.
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
String bestProvider = lm.getBestProvider(new Criteria(), true);    
mMyLocationListener = new MyLocationListener();
lm.requestLocationUpdates(bestProvider, 0, 0, mMyLocationListener);

private class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location location) {
        // Do what you need to do with the longitude and latitude here.
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

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

You should also remember to remove the location listener as soon as you no longer need it:

LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.removeUpdates(mMyLocationListener);
mMyLocationListener = null;

I dont want location updates. I just want to find the location once. I have this code inside a class that implements a location listener. — Brahadeesh, Aug 01 '11 at 15:46
Even if you only want the location once, I think that this is the only way to get it, if you don't have a last known location. Register a listener and as soon as you get an update, remove that listener and use the location you get. However, if the problem is that the emulator doesn't provide you with one, see Ovidiu's answer. :) — TofferJ, Aug 01 '11 at 15:54
Yeah. Please check my last comment on his answer. Thank you for your answer though. — Brahadeesh, Aug 01 '11 at 15:59

location manager android problem

2 Answers2