Android cannot retrieve location

Question

I have created the below code to simply get the most recent latitude and longitude without needing the user to turn on GPS but simply rely on wifi or network for positioning. Upon running the app, it simply returns the toast "The Lat is 0.0 and Long is 0.0". I know this should work because I have downloaded the sample code here: https://github.com/googlesamples/android-play-location/tree/master/BasicLocationSample, and adapted to work in my code.

How can I get this to work?

public class MainActivity extends FragmentActivity implements GoogleApiClient.ConnectionCallbacks, OnConnectionFailedListener  {

    public static double lat;
    public static double lng;

    ViewPager viewPager = null;

    /**
     * Provides the entry point to Google Play services.
     */
    protected GoogleApiClient mGoogleApiClient;

    /**
     * Represents a geographical location.
     */
    protected Location mLastLocation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        buildGoogleApiClient();

        String text = "The Lat is " + lat
                + " and Long is " + lng;

        Toast.makeText(getBaseContext(), text, Toast.LENGTH_LONG).show();

        };

        // Assign list to actionbar
        actionBar.setListNavigationCallbacks(aAdpt, null); // DEPRACATED

    } 


    /**
     * Builds a GoogleApiClient. Uses the addApi() method to request the LocationServices API.
     */
    protected synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (mGoogleApiClient.isConnected()) {
            mGoogleApiClient.disconnect();
        }
    }

    /**
     * Runs when a GoogleApiClient object successfully connects.
     */
    @Override
    public void onConnected(Bundle connectionHint) {
        // Provides a simple way of getting a device's location and is well suited for
        // applications that do not require a fine-grained location and that do not need location
        // updates. Gets the best and most recent location currently available, which may be null
        // in rare cases when a location is not available.
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (mLastLocation != null) {
            lat = mLastLocation.getLatitude();
            lng = mLastLocation.getLongitude();
        } else {
            Toast.makeText(this,"No location detected", Toast.LENGTH_LONG).show();
        }
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
        // Refer to the javadoc for ConnectionResult to see what error codes might be returned in
        // onConnectionFailed.

    }


    @Override
    public void onConnectionSuspended(int cause) {
        // The connection to Google Play services was lost for some reason. We call connect() to
        // attempt to re-establish the connection.

        mGoogleApiClient.connect();
    }
}

}

Answer 1

"lat", "lng", and "mLastLocation" isn't set or valid until onConnected() has been executed. You need to understand that this operation is asynchronous -- that is, the location doesn't come back immediately but is provided later on. This would have been obvious if you tested whether "mLastLocation" was null or not when you made that toast.