Android: adding progressdialog to my current location finder crashes app. Need to find location once

Question

The location class:

public class MyLocationListener implements LocationListener{
         private Context cnt;
         private ProgressDialog d;
    public MyLocationListener(Context cnt){
        this.cnt = cnt;

         this.d.show(cnt, "", "Finding your location...");

    }

     @Override
     public void onLocationChanged(Location loc){

     loc.getLatitude();
     loc.getLongitude();
     this.d.dismiss();
     String Text = "My current location is: " +"Latitud = " + loc.getLatitude() +"Longitud = " + loc.getLongitude();

     Toast.makeText( getApplicationContext(),Text,Toast.LENGTH_SHORT).show();
     }


     @Override

     public void onProviderDisabled(String provider) {

     Toast.makeText(getApplicationContext(),"Gps Disabled",Toast.LENGTH_SHORT ).show();

     }


     @Override

     public void onProviderEnabled(String provider) {

     Toast.makeText(getApplicationContext(),"Gps Enabled",Toast.LENGTH_SHORT).show();

     }


     @Override
     public void onStatusChanged(String provider, int status, Bundle extras){


     }

     }/* End of Class MyLocationListener */

This is how I implement it:

/* Use the LocationManager class to obtain GPS locations */

                LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
                LocationListener mlocListener = new MyLocationListener(cnt);
                mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);

I get a null pointer exception error when I add that progress dialog. When I take it out everything works fine.

Is the progress dialog conflicting with the Toast message?

EDIT:

It looks like onLocationChanged, well, changes often, so it ends up dismissing a dialog that was already dismissed.

Is there a way to only have the location found once?

Answer 1

with a boolean, but that won't be the best practice. in your case you would add an if before you dismiss your progressDialog:

if (this.d.isShowing())
    this.d.dismiss();