Android ListView does not update dynamic location data - android-listview

Question

I have researched this topic thoroughly and found similar questions on StackOverflow but not specific enough for my question. I am trying to update my ListView with a SimpleCursorAdapter. I have a button, "Get Network Location" that when I press it, it dynamically populates my ListView with new location data (id, lat, lon, acc, time) every time the location changes inside method "onLocationChanged". This is done through adding the new location data to the database and setting the cursor to the adapter.
So it works fine until the "Back" button is pressed or the phone changes orientation. In onResume, the listview becomes empty, so I had to open the database again and set the cursor to the adapter and the adapter to listview again. This populates the listview with complete data from database at the time that "onResume" is called.
However, when a new location data gets added in "onLocationChanged", the new data doesn't populate the listview, until "onResume" gets called again. adapter.notifyDataSetChanged is called both in "onResume" an "onLocation" changed but to no avail. My guess is the listview has changed to a different one after "onCreate" is called but I don't know how to resolve that.
Please anyone with knowledge on this issue let me know what is wrong with my code.
Here's my code:
public class MainActivity extends Activity {
LocationManager locMan;
String provider;
Boolean netWork_enabled = false;
private static long MINTIME;
private static float MINDIS;
Cursor cursor;
NetworkScanDB GeoLocInfoDb;
String row;
double lat;
double lon;
double accur;
double time;
EditText etMinTime;
EditText etMinDis;
ListView lv;
SimpleCursorAdapter sd;
String[] columns;
int[] to;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// initialize lv
lv = (ListView) findViewById(R.id.listView1);
// getting min time and distance from edit text
etMinTime = (EditText) findViewById(R.id.et_minTime);
etMinDis = (EditText) findViewById(R.id.et_minDis);
// initiating location
locMan = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
provider = locMan.NETWORK_PROVIDER;
try {
netWork_enabled = locMan.isProviderEnabled(provider);
} catch (Exception ex) {
}
columns = new String[] { NetworkScanDB.Key_RowID,
NetworkScanDB.Key_Lat, NetworkScanDB.Key_Lon,
NetworkScanDB.Key_Accur, NetworkScanDB.Key_Time };
to = new int[] { R.id.t0, R.id.t1, R.id.t2, R.id.t3, R.id.t4 };
sd = new SimpleCursorAdapter(MainActivity.this, R.layout.nsrow, cursor,
columns, to, 0); // had to change to api 11., 0=no query
}
LocationListener locationListenerNetwork = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
try {
GeoLocInfoDb = new NetworkScanDB(MainActivity.this);
GeoLocInfoDb.open();
// insert row into DB
GeoLocInfoDb.insertGeoLocInfo(location.getLatitude(),
location.getLongitude(), location.getAccuracy(),
location.getTime());
cursor = GeoLocInfoDb.getGeoLocInfoCursor();
sd = new SimpleCursorAdapter(MainActivity.this, R.layout.nsrow,
cursor, columns, to, 0); // had to change to api 11.,
// 0=no query
Toast.makeText(getApplicationContext(),
"added new location onLocationChanged",
Toast.LENGTH_LONG).show();
// lv = (ListView) findViewById(R.id.listView1);
sd.notifyDataSetChanged();
lv.setAdapter(sd);
GeoLocInfoDb.close();
} catch (Exception e) {
Log.w("nwscan", e.toString());
}
}
#Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
#Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
};
public void getNetworkLocation(View v) {
MINTIME = Long.parseLong(etMinTime.getText().toString());
MINDIS = Float.parseFloat(etMinDis.getText().toString());
if (netWork_enabled) {
locMan.requestLocationUpdates(provider, MINTIME, MINDIS,
locationListenerNetwork);
} else {
Toast.makeText(getApplicationContext(), "network not enable",
Toast.LENGTH_LONG).show();
}
}
#Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Toast.makeText(getApplicationContext(), "onResume ", Toast.LENGTH_LONG)
.show();
GeoLocInfoDb = new NetworkScanDB(MainActivity.this);
GeoLocInfoDb.open();
cursor = GeoLocInfoDb.getGeoLocInfoCursor();
sd = new SimpleCursorAdapter(MainActivity.this, R.layout.nsrow, cursor,
columns, to, 0); // had to change to api 11., 0=no query
sd.notifyDataSetChanged();
lv.setAdapter(sd);
}
...
}