Question

Can you help me with that.. application started to crash when I added the geocoder to get the name of the city by using latitude and longitude..

    double latitude, longitude;
    private TextView lala;

    LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 
    Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
    longitude = location.getLongitude();
    latitude = location.getLatitude();
    final LocationListener locationListener = new LocationListener() {
        public void onLocationChanged(Location location) {
            longitude = location.getLongitude();
            latitude = location.getLatitude();
        }

        public void onProviderDisabled(String arg0) {
            // TODO Auto-generated method stub

        }

        public void onProviderEnabled(String arg0) {
            // TODO Auto-generated method stub

        }

        public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
            // TODO Auto-generated method stub

        }
    };

    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
    lala = (TextView) findViewById(R.id.textView1);

    Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());   
    List<Address> myList = null;
    try {
        myList = myLocation.getFromLocation(latitude, longitude, 1);
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }


    lala.setText((CharSequence) myList);

Answer 1

lm.getLastKnownLocation can return null, and then tou try to getLongitude() you’ll get NullPointerException

Also lala.setText((CharSequence) myList); can do the same (throw Exception) cause’ myList can be null here (if Geocoder is failed).

EDIT
To deal with exception in Geocoder consider the following checklist

1. Make sure your latitude and longitude are not null
2. Make sure what -90 <= latitude <= 90 and -180 <= longitude <= 180
3. Make sure you are having available network connection

EDIT2
Improved code

private TextView lala;

LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 
Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);

if(location != null) {
    showMyAddress(location);
}

final LocationListener locationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
        showMyAddress(location);
    }

    public void onProviderDisabled(String arg0) {
        // TODO Auto-generated method stub

    }

    public void onProviderEnabled(String arg0) {
        // TODO Auto-generated method stub

    }

    public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
        // TODO Auto-generated method stub

    }
};

lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
lala = (TextView) findViewById(R.id.textView1);



// Also declare a private method

private void showMyAddress(Location location) {
    double latitude = location.getLatitude();
    double longitude = location.getLongitude();
    Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());   
    List<Address> myList;
    try {
        myList = myLocation.getFromLocation(latitude, longitude, 1);
        if(myList.size() == 1) {
            lala.setText(myList.get(0).toString());             
        }
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
}