title: How can stop onLocationChanged() method using button click?
body: <p>I'm beginner for android development.I use Gps service implementing LocationListener.I want to stop onLocationChanged() method using button click.
  I'm try to do this assigning null value to locationManager variable but it doesn't work it.</p>
  
  <pre><code>public class TabFragment1 extends Fragment implements LocationListener {
      ImageButton btnRUN;
      ImageButton btnSTOP;
      private LocationManager locationManager;
      Context ctx;
      private double lat_new, lon_new = 0.0;
  
  
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
          ctx = container.getContext();
          View view = inflater.inflate(R.layout.tab_fragment_1, container, false);
  
          initializeApp(view);
          return view;
      }
  
  
      private void initializeApp(View view) {
          btnRUN = (ImageButton) view.findViewById(R.id.btnRun);
          btnSTOP= (ImageButton) view.findViewById(R.id.btnStop);
  
  
          btnRUN.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  runOnClick();
              }
          });
  
          btnSTOP.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  stopOnClick();
  
              }
          });
  
      }
      public void stopOnClick(){
            locationManager =null;
      }
  
      public void runOnClick() {
  
  
  
          locationManager = (LocationManager) ctx.getSystemService(Context.LOCATION_SERVICE);
          locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 3000, 10, this);
  
  
      }
  
  
      @Override
      public void onLocationChanged(Location location) {
          lat_new=location.getLatitude();
          lon_new=location.getLongitude();
  
  
  
          String str="Lat :"+lat_new +"Lon :"+lon_new;
          Toast.makeText(ctx,str,Toast.LENGTH_LONG).show();
      }
  
      @Override
      public void onStatusChanged(String provider, int status, Bundle extras) {
  
      }
  
      @Override
      public void onProviderEnabled(String provider) {
          Toast.makeText(ctx, "Gps turned on ", Toast.LENGTH_LONG).show();
      }
  
      @Override
      public void onProviderDisabled(String provider) {
          Toast.makeText(ctx, "Gps turned off ", Toast.LENGTH_LONG).show();
      }
  
  
  } 
  </code></pre>