How to move marker in googlemap while getting different latitude,longitude in android

Question

I am developing android application and my requirement is, how to move marker in google map while latitude and longitude is changing which means tracking device system

This is my json

{
 "gpslocation": [
                   {
                      "Latitude":"12.9789702",
                      "Longitude":"77.6411031",
                      "UpdatedOn":"2015-06-02 14:09:02"
                   }
                ]
}

This is my main activity

  private static String url = "http://example.com/android/gps/latlong.php";

            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.gmap_direction);

                pd = new ProgressDialog(Bustracking.this);
                pd.setMessage("Please wait...");
                pd.setCanceledOnTouchOutside(false);
                pd.show(); 

                new AsyncTask<Void, Void, Void>()
                {
                    @Override
                    protected Void doInBackground(Void... params)
                    {
                        callAsynchronousTask();

                        return null;
                    }

                    @Override
                    protected void onPostExecute(Void result)
                    {
                    }
                }.execute();


            }

       public void callAsynchronousTask() {
           timer = new Timer();
           timer.scheduleAtFixedRate(new TimerTask() {

             @Override
             public void run() {
                 location();     
             }
          }, 0, 1000);
         }

    public void location(){         

     List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("key", "agile89rise98"));
        params.add(new BasicNameValuePair("username", un));
        params.add(new BasicNameValuePair("type", "parent"));

         // getting JSON string from URL
        JSONObject json = jParser.makeHttpRequest(url, "GET", params);

     try {                              
             JSONArray a= json.getJSONArray(TAG_SUCCESS);
             JSONObject c = a.getJSONObject(0);

             // Storing  JSON item in a Variable
         final String latitudee = c.getString("Latitude");
         final String longitudee = c.getString("Longitude");
         final String updatedon = c.getString("UpdatedOn");
         pd.dismiss();

             runOnUiThread(new Runnable(){

                @Override
               public void run() {

               try {
                        // Loading map
                        initilizeMap();

                   // Changing map type
                        googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
                        googleMap.setMyLocationEnabled(true);
                        // Enable / Disable zooming controls
                        googleMap.getUiSettings().setZoomControlsEnabled(false);
                        // Enable / Disable my location button
                        googleMap.getUiSettings().setMyLocationButtonEnabled(true);
                        // Enable / Disable Compass icon
                        googleMap.getUiSettings().setCompassEnabled(true);
                        // Enable / Disable Rotate gesture
                        googleMap.getUiSettings().setRotateGesturesEnabled(true);
                        // Enable / Disable zooming functionality
                        googleMap.getUiSettings().setZoomGesturesEnabled(true);
                        double latitude =  Double.parseDouble(latitudee);
                        double longitude = Double.parseDouble(longitudee);

          MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title(updatedon);
          marker.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_YELLOW));

                            googleMap.addMarker(marker);

                                CameraPosition cameraPosition = new CameraPosition.Builder()
                                        .target(new LatLng(latitude,
                                                longitude)).zoom(25).build();

                                googleMap.animateCamera(CameraUpdateFactory
                                        .newCameraPosition(cameraPosition));



                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    } 

                  });

            } catch (final JSONException e) {
                 pd.dismiss();
                 runOnUiThread(new Runnable(){

                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(), "Bus Service Not Available", Toast.LENGTH_SHORT).show();
                            e.printStackTrace();
                        }
                 });
            }

        }

My lat and long is continuously changing according to device location and i am gettting lat and long from json url and display it in google map i have one AsyncTask in my oncreate function and i am calling one function called callAsynchronousTask(); in doinbackground This is function is excuting every one second because i need continuous lat,long from json url and i am calling one more funtion from callAsynchronoustask called location(); This function for retrieving lat,long value and display it in googlemap

i am calling location(); each and every seconds because of getting continous lat,long values. Now My output is coming like creating marker for each every movement so whenever i am getting latlong at that it is creating new marker

My Reqiurement:- It should not create new marker, same marker should move whenever i am getting different latlong values

Could you please tell me how to do it?

Answer 1

Do this between your initializeMap() method and googleMap.setMapType() method put this line:

 // Loading map
                            initilizeMap();
                          googleMap.clear();   // put this line

                       // Changing map type
                            googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);