"Location not available"?

Question

In my android app that I want to develope, I would like the users can find their position. To do this I have this code in the MainActivity but on the device (when i run it) it can't find latitute longitude and the address.Why?

public class MainActivity extends Activity implements LocationListener {
private TextView latituteField;
private TextView longitudeField;
private TextView addressField; //Add a new TextView to your activity_main to display the address
private LocationManager locationManager;
private String provider;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    latituteField = (TextView) findViewById(R.id.TextView02);
    longitudeField = (TextView) findViewById(R.id.TextView04);
    addressField = (TextView) findViewById(R.id.TextView05); //Make sure you add this to activity_main


    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

    Criteria criteria = new Criteria();
    provider = locationManager.getBestProvider(criteria, false);
    Location location = locationManager.getLastKnownLocation(provider);


    if (location != null) {
        System.out.println("Provider " + provider + " has been selected.");
        onLocationChanged(location);
    } else {
        latituteField.setText("Location not available");
        longitudeField.setText("Location not available");
    }
}


@Override
protected void onResume() {
    super.onResume();
    locationManager.requestLocationUpdates(provider, 400, 1, this);
}


@Override
protected void onPause() {
    super.onPause();
    locationManager.removeUpdates(this);
}

@Override
public void onLocationChanged(Location location) {

    double lat = location.getLatitude();
    double lng = location.getLongitude();

    Geocoder geoCoder = new Geocoder(this, Locale.getDefault());
    StringBuilder builder = new StringBuilder();
    try {
        List<Address> address = geoCoder.getFromLocation(lat, lng, 1);
        int maxLines = address.get(0).getMaxAddressLineIndex();
        for (int i=0; i<maxLines; i++) {
            String addressStr = address.get(0).getAddressLine(i);
            builder.append(addressStr);
            builder.append(" ");
        }

        String fnialAddress = builder.toString(); //This is the complete address.

        latituteField.setText(String.valueOf(lat));
        longitudeField.setText(String.valueOf(lng));
        addressField.setText(fnialAddress); //This will display the final address.

    } catch (IOException e) {}
    catch (NullPointerException e) {}
}

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


}

@Override
public void onProviderEnabled(String provider) {
    Toast.makeText(this, "Enabled new provider " + provider,
            Toast.LENGTH_SHORT).show();

}

@Override
public void onProviderDisabled(String provider) {
    Toast.makeText(this, "Disabled provider " + provider,
            Toast.LENGTH_SHORT).show();
}

}

Answer 1

Note: This is an old answer which did not help solve the particular problem. However, it is valuable information so I don't delete it.

The blinking GPS icon is a good sign. It means that your app is asking the operating system for the location and the operating system tries to fetch it.

The blinking indicates that the operating system did not complete fetching the location via GPS. If this problem persists for, e.g. more than 1 or 2 minutes, it can have the following reasons:

• You do not receive the GPS signal (e.g. because you are in a building with too thick walls).
• You do not have a data connection to the internet (on some versions of phones and/or android, GPS doesn't work without data connection. Sounds stupid, but it's true. I am a proud owner of such a phone.)
• There is some other bug that causes your GPS to be in a state where it does not generate any more location updates. This happened for me sometimes and I do not know any more background info. After a reboot of the phone, it always worked again.

Answer 2

I've compiled your example and tested it on a Galaxy S2. Here are my findings:

You have code in your examples for two different approaches of getting the location. One approach is to use LocationManager.getLastKnownLocation(...) to fetch the location directly and the other approach is to implement the LocationListener interface and registering for location updates to get notified about new location updates later.

Upfront info: I got the second approach work fine, but I did not get the approach with the getLastKnownLocation method to work reliably.

The location fetching does not work because as provider, "network" is returned. This happens although GPS is on. The subsequent effect is that, because I have the network location provider switched off, the getLastKnowLocation method returns null as documented there: "If the provider is currently disabled, null is returned." (from getLastKnownLocation )

You can fix this by changing

provider = locationManager.getBestProvider(criteria, false);

to

provider = locationManager.getBestProvider(criteria, true);

.

This will give you the GPS provider, if it is available (switched on). However, the getLastKnownLocation(...) method still returns null for me, although the correct provider (gps) is selected and the provider is available. That means that the documentation of the getLastKnownLocation method is lacking information about another case when it returns null. This seems to be because no last known location was saved for this provider. You can not know if this is the case when starting your application, so you can not rely on this method returning a non-null value at application startup.

And here is the good news: Now that we got the correct location provider, the location updates through the second approach (the registering for future location update notifications) works as expected through the gps provider. Updates are coming in and the locations are shown and updated in the textfields on my test phone.

Answer 3

My guess would be that the best provider is not enabled. try calling getBestProvider(criteria, true) also Log.d the provider and you can use isProviderEnabled(provider) to see if the provider is enabled.