Ortungssystem im ASyncTask

double Latitude;
double Longitude;
String Ortungsprovider = null;

GetPosition getpositiontask = new GetPosition(boolean *OB GPS VERSUCHT WERDEN SOLL*, int *MAX MINUTEN DES ALTEN DATENSATZES*, boolean *OB EIN PROGRESSDIALOG ANGEZEIGT WERDEN SOLL*, boolean *OB DAS PROGRESSDIALOG EIN ABBRECHEN HABEN SOLL*);
getpositiontask.execute();

private class GetPosition extends AsyncTask<Void, Void, Location> implements LocationListener{
    	
        long old_Datensatz;
        private Location location;
        private LocationManager lm;
        private boolean use_gps;
        private boolean ist_gps_aktiv = false;
        private boolean ist_network_aktiv = false;
        private boolean ist_passive_aktiv = false;
        private boolean zeige_progressbar;
        private boolean zeige_progresskill;
        private String useprovider;
        private long minTime = 0;
        private float minDistance = 0;
        
        private GetPosition(boolean benutzeGPS, int minuten, boolean zeigeProgress, boolean zeigeAbbrechen){
        	
        	use_gps = benutzeGPS;
        	old_Datensatz = minuten*60*1000;
        	zeige_progressbar = zeigeProgress;
        	zeige_progresskill = zeigeAbbrechen;
        }

        ProgressDialog progressload = new ProgressDialog(*Activity*.this);
        
        protected void onPreExecute(){
        	
        	lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        	
        	ist_gps_aktiv = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
    		ist_network_aktiv = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
    		ist_passive_aktiv = lm.isProviderEnabled(LocationManager.PASSIVE_PROVIDER);	
    		
    		if(use_gps && ist_gps_aktiv){
    			lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, minTime, minDistance, this);
    			useprovider = "GPS_PROVIDER";
    			progressload.setMessage("Suche Standortposition via GPS ...");
    		}else if(ist_network_aktiv){
    			lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, minTime, minDistance, this);
    			useprovider = "NETWORK_PROVIDER";
    			progressload.setMessage("Suche Standortposition via Mobilfunknetz ...");
    		}else if(ist_passive_aktiv){
    			lm.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER, minTime, minDistance, this);
    			useprovider = "PASSIVE_PROVIDER";
    			progressload.setMessage("Suche Standortposition ...");
    		}
    		
    		Ortungsprovider = useprovider;
    		
    		System.out.println("Benutze \"" + useprovider + "\" zum orten ...");
        	
        	progressload.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        	progressload.setCancelable(false);
        	
        	if(zeige_progresskill){
        		System.out.println("Zeige Abbrechen-Button an ...");
        		progressload.setButton(DialogInterface.BUTTON_NEGATIVE, "Abbrechen", new DialogInterface.OnClickListener() {
        		    public void onClick(DialogInterface dialog, int which) {
        		        dialog.dismiss();
        		        killprogress();
        		    }
        		});
        	}else{
        		System.out.println("Zeige keinen Abbrechen-Button an ...");
        	}
        	
        	if(zeige_progressbar){
        		progressload.show();
        		System.out.println("Zeige ProgressDialog an ...");
        	}else{
        		System.out.println("Zeige keinen ProgressDialog an ...");
        	}

            
        }
        
        private void killprogress(){
	        lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
            lm.removeUpdates(this);
            Ortungsprovider = null;
            Toast.makeText(getApplicationContext(), "Standortsuche wurde abgebrochen.", Toast.LENGTH_LONG).show();
        }

        protected Location doInBackground(Void... params){
            
        	//Versuche den letzten Standort zu bekommen - spart Akku
            Location lastLocation = lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
            
            // Wenn der letzte Standort älter als old_Datensatz ist, suche einen neuen
            if ((System.currentTimeMillis() - lastLocation.getTime() > old_Datensatz) || lastLocation == null){
            	
                while (location == null){
                    try {
                    	Thread.sleep(100);
                    }catch (Exception ex) {}
                }
                return location;
            }
            return lastLocation;
        }

        protected void onPostExecute(Location location){
            progressload.dismiss();
            lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
            lm.removeUpdates(this);  	
    	Latitude = location.getLatitude();
    	Longitude = location.getLongitude();
    	
    	System.out.println("Latitude: " + Latitude + "\nLongitude: " + Longitude);
        }

        public void onLocationChanged(Location newLocation){
            location = newLocation;
        }

        public void onProviderDisabled(String provider) {}
        public void onProviderEnabled(String provider) {}
        public void onStatusChanged(String provider, int status, Bundle extras) {}
        
    }