How to correctly animate a map created in Android

I'm trying to update my map so that the map automatically moves to centre the marker. I want it such that if I move around, after 5 seconds, the map will animate itself to move such that the marker is central again.

Here is the code:

public class TrackDifferentLocation extends AppCompatActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    LatLng mLatlng;
    String json_string;
    public static TextView data;
    LatLng latLng = null;

    @Override
    protected void onCreate (Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //Toast.makeText(this, "Tracking location...", Toast.LENGTH_LONG).show();
        setContentView(R.layout.activity_track_different_location);
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map_fragment);
        mapFragment.getMapAsync(this);
            getSupportActionBar().setDisplayShowHomeEnabled(true);
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        //new FetchJSON.execute(); //Not valid syntax
        new FetchJSON().execute();
    }

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    Log.i("", "onMapReady()");
    displayMarkers();
}
    private void displayMarkers(){
        if (mMap == null)return;
        //If mLatlng is null (as the Async task has not finished, then nothing will happen.
        if(mLatlng == null) return;
        //The camera and map will then update to the new location with zoom.
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(mLatlng, 17));
        mMap.addMarker(new MarkerOptions().position(mLatlng).title(String.valueOf(mLatlng)));
    }

    //Part of menu see following
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == android.R.id.home){
            //ends the activity
            this.finish();
        }
        switch (item.getItemId()) {
            case R.id.mapTypeNone:
                mMap.setMapType(GoogleMap.MAP_TYPE_NONE);
                break;
            case R.id.mapTypeNormal:
                mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
                break;
            case R.id.mapTypeTerrain:
                mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);
                break;
            case R.id.mapTypeSatellite:
                mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
                break;
            case R.id.mapTypeHybrid:
                mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
                break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }
    class FetchJSON extends AsyncTask<String, Integer, LatLng> {
        String JSONStr = "";
        String name, address, type = "";
        String lat = "";
        String lng = "";
        String id = "";
        //double lat, lng;
        int idInt;
        double latDouble = -1;
        double lngDouble = -1;

        protected LatLng doInBackground(String... args) {
            //LatLng latLng = null;
            try {
                //URL url = new URL("https://api.myjson.com/bins/ehzqu");
                URL url = new URL("https://api.myjson.com/bins/sv5vm");
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                Log.d("BufferedReader: ", String.valueOf(bufferedReader));
                String line = "lind";
                while (line != null) {
                    line = bufferedReader.readLine();
                    JSONStr = JSONStr + line;
                }
                Log.d("", JSONStr);
                JSONObject obj = new JSONObject(JSONStr);
                JSONArray array = obj.getJSONArray("server response");
                for (int i = 0; i < array.length(); i++) {
                    JSONObject o = array.getJSONObject(i);
                    id = o.optString("id");
                    name = o.optString("name");
                    address = o.optString("address");
                    lat = o.optString("lat");
                    lng = o.optString("lng");
                    Log.d("lat: ",lat);
                    latDouble = Double.parseDouble(lat);
                    lngDouble = Double.parseDouble(lng);
                    latLng = new LatLng(latDouble, lngDouble);
                    Log.i("JSON Values", lat + " " + lng);
                    type = o.optString("type");
                }

            } catch (Exception ex) {
                Log.e(TAG, "FetchJSON --- " + ex.getMessage());
            }
            return latLng;
        }

        protected void onPostExecute(LatLng latLng) {
            if (latLng != null) {
                mLatlng = latLng;
                displayMarkers();
            }
        }

}
}

Please note, for the question I have removed all imports and package.

To demonstrate how this can work I have changed the code which is more applicable to your code:

 int index = 0;
 private void loadLocation() {
     new FetchJSON().execute();
     startAutoHandler();
 }


 class FetchJSON extends AsyncTask<String, Integer, LatLng> {

     @Override
     protected LatLng doInBackground(String... params) {
         LatLng latLng = null;
         try {
             URL url = new URL("https://api.myjson.com/bins/sv5vm");
             HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
             InputStream inputStream = httpURLConnection.getInputStream();
             BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

             StringBuilder stringBuilder = new StringBuilder();
             String line = "";
             while ((line = bufferedReader.readLine()) != null) {
                 stringBuilder.append(line).append("\n");
             }
             bufferedReader.close();

             String json = stringBuilder.toString();

             Log.e(TAG, "Return = " + json);
             String lat= "";
             String lng= "";
             JSONObject obj = new JSONObject(json);
             JSONArray array = obj.getJSONArray("server response");
             for(int i = 0; i < array.length(); i++){
                 JSONObject o = array.getJSONObject(i);

                 lat = o.optString("lat");
                 lng = o.optString("lng");
             }

             Log.e(TAG, "Lat = " + lat);
             Log.e(TAG, "lng = " + lng);

             index++;

             double adjustLat = 0.1 * index;
             double adjustLng = 0.01 * index;

             double latDouble = Double.parseDouble(lat) + adjustLat;
             double lngDouble = Double.parseDouble(lng) + adjustLng;

             latLng = new LatLng(latDouble, lngDouble);
         }
         catch (Exception ex) {
             Log.e(TAG, "doInBackground --- " + ex.getMessage());
         }
         return latLng;
     }


     @Override
     protected void onPostExecute(LatLng latLng) {
         try{
             if(latLng != null){
                 mLatLng = latLng;
                 displayMarker();
             }

         }
         catch(Exception ex){
             Log.e(TAG, "onPostExecute" + ex.getMessage());
         }
     }

 }

 private void displayMarker(){
     if(mMap == null) return;
     if(mLatLng == null) return;

     mMap.clear();

     MarkerOptions markerOption = new MarkerOptions();
     markerOption.position(mLatLng);
     CameraUpdate loc = CameraUpdateFactory.newLatLngZoom(mLatLng, 10.3f);
     mMap.animateCamera(loc);
     mMap.addMarker(markerOption);
 }

 Handler mAutoHandler = new Handler();
 long delay = 2000l; //this delay is in ms change as needed

 private void startAutoHandler(){
     try{
         Log.e(TAG, "startAutoHandler");
         mAutoHandler.postDelayed(mAutoRunnable, delay);
     }
     catch (Exception ex){
         Log.e(TAG, ex.getMessage());
     }
 }


 private Runnable mAutoRunnable = new Runnable() {
     @Override
     public void run() {
         new FetchJSON().execute();
         mAutoHandler.postDelayed(mAutoRunnable, delay);
     }
 };

 private void stopAutoHandler(){
     mAutoHandler.removeCallbacks(mAutoRunnable);
 }

You will need to call stopAutoHandler(); in your onPause() method. Otherwise it will carry on and can cause some real issues!