Question

hi i am doing a application based on gps,i use gps as service for my project ,when gps is turn on it show the location correctly and application runs fine ,but after that i exit from my app completely and when the gps turned off the it shows crash message.which mean even if l leave or exit my app the service class is still running ,and also app get crash if i turn off gps when app is running ,but if i did not turn of gps it work fine.Now how can i solve this problem. i will show my service class used for gps

public class Gps_Service extends Service {

TextView txtv;
List<Address> myList;
String addressStr;
LocationManager lm;
LocationListener ll;
SQLiteDatabase DiaryDB = null;

@Override
public IBinder onBind(Intent arg0) {
    // TODO Auto-generated method stub
    return null;
}
@Override
public void onCreate() {
    super.onCreate();
    System.out.println("@@@@@@@@@@@ serviceOnCreate");
//      Toast.makeText(this, "GPS Service started(Diary)", Toast.LENGTH_LONG).show();       

    lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    ll = new mylocationlistener();
    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);

}

@Override
public void onDestroy() {
    super.onDestroy();

//      Toast.makeText(this, "GPS Service Destroyed(Diary)", Toast.LENGTH_LONG).show();

    lm.removeUpdates(ll);
    System.out.println("@@@@@@@@@@@ inside ONDESTROY GPS listener removed");
}

 @Override
    public int onStartCommand(Intent intent, int flags, int startId) 
    {
        Log.v("StartServiceAtBoot", "StartAtBootService -- onStartCommand()");          
//          Toast.makeText(this, "Service started", Toast.LENGTH_LONG).show();
        // We want this service to continue running until it is explicitly
        // stopped, so return sticky.
        return START_STICKY;
    }

 private class mylocationlistener implements LocationListener
    {

        public void onLocationChanged(Location location) 
        {
            if (location != null) {
                Geocoder myLocation = new Geocoder(Gps_Service.this, Locale.getDefault());
//                  Toast.makeText(MyService.this,location.getLatitude() + "       " + location.getLongitude()   +"\n",Toast.LENGTH_LONG).show();
//                  DiaryDB = MyService.this.openOrCreateDatabase("DIARY_DATABASE", MODE_PRIVATE, null);
//                  DiaryDB.execSQL("INSERT INTO Locations(LATITUDE, LONGITUDE) VALUES('"   +location.getLatitude()+"','"+location.getLongitude()+"')");
//                  DiaryDB.close();
            //  ParseTweetsActivity.latitude  = ""+location.getLatitude();
                //ParseTweetsActivity.longitude = ""+location.getLongitude();
                AndroidGoogleMapsActivity.lats   = Double.parseDouble(""+location.getLatitude());
                AndroidGoogleMapsActivity.longt = Double.parseDouble(""+location.getLongitude());
            Advertiser_get_direction.latitudefrom = Double.parseDouble(""+location.getLongitude());
                Advertiser_get_direction.longtitudefrom = Double.parseDouble(""+location.getLongitude());

                AndroidGoogleMapsActivity.longt = Double.parseDouble(""+location.getLongitude());
                System.out.println("saaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"+AndroidGoogleMapsActivity.lats);
          //    ParseTweetsActivity.load();
                try 
                {
                    myList = myLocation.getFromLocation(location.getLatitude(),location.getLongitude(), 1);

                } catch (IOException e) {

                    e.printStackTrace();
                }

                if(myList!=null)
                {

                    Address address = (Address) myList.get(0);

                    addressStr = "";
                    addressStr += address.getAddressLine(0) + "\n";
                    addressStr += address.getAddressLine(1) + "\n";
                    addressStr += "Country name  "+address.getCountryName() + "\n";
                    addressStr += "Locality      "+address.getLocality() + "\n";
                    addressStr += "Country code  "+address.getCountryCode() + "\n";
                    addressStr += "Admin Area    "+address.getAdminArea() + "\n";
                    addressStr += "SubAdmin Area "+address.getSubAdminArea() + "\n";
                    addressStr += "PostalCode    "+address.getPostalCode() + "\n";

                //  txtv.append(location.getLatitude() + "    " + location.getLongitude() +"\n");
                //  txtv.append(addressStr+"\n");
                    System.out.println(location.getLatitude() + "    " + location.getLongitude() +"\n");
                    lm.removeUpdates(ll);
                }
            }
        }
        public void onProviderDisabled(String provider) 
        {
//              Toast.makeText(MyService.this,"Provider Disabled",Toast.LENGTH_LONG).show();
            txtv.setText("");
        }
        public void onProviderEnabled(String provider)
        {
//              Toast.makeText(MyService.this,"Provider Enabled.....",Toast.LENGTH_LONG).show();
        }
        public void onStatusChanged(String provider, int status, Bundle extras)
        {
        }
   }

}

Answer 1

You have declared a TextView within your Service. That’s not good. TextView is a UI component and doesn’t belong on the service.

In your onProviderDisabled() method, you call txtv.setText(""); which will probably crash because txtv is null. This is probably why your app is crashing when you disable GPS.