How To Refresh The Marker On The Map?

I have just 2 Markers on the Map 1- I want to show the bothe markers with max zoom as possible 2- I want after that refresh the markers position with a timer for example. I want to

Solution 1:

You need to call load_locations_from_server() method after map ready which is in onMapReady() method.

Read more at https://developers.google.com/maps/documentation/android-api/start

To set the new location of marker, you just need to use:

Marker.setPosition(LatLng latlng);

So you need to create two variables for the markers.

private Marker mMarkerA; private Marker mMarkerB;

Then in your onMapReady(), initialize them:

@OverridepublicvoidonMapReady(GoogleMap googleMap) {
  mMap = googleMap;

  ...

  mMarkerA = mMap.addMarker(newMarkerOptions().position(a_local).title("a") 
            .snippet("xxx")
            .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_yellow))).showInfoWindow();

  mMarkerB = mMap.addMarker(newMarkerOptions().position(b_local).title("b")
            .snippet("yyy")
            .icon(BitmapDescriptorFactory.fromResource(R.drawable.markerb))).showInfoWindow();
  ...
}

Then, you can refresh them when you get the location from the server:

a_lat=respons.getString("a_lat");
a_lon=respons.getString("a_lon");
b_lat=respons.getString("b_lat");
b_lon=respons.getString("b_lon");

// refresh marker
mMarkerA.setPosition(new LatLng(a_lat, a_lon));
mMarkerA.setPosition(new LatLng(b_lat, b_lon));

Show Both Marker

To show both marker with extra padding, you can use LatLngBounds like the following method:

privatevoidzoomToShowBothPoints(LatLng firstLatLng, LatLng secondLatLng) {
    LatLngBoundsbounds=newLatLngBounds.Builder().include(firstLatLng).include(secondLatLng).build();

    PointdisplaySize=newPoint();
    getWindowManager().getDefaultDisplay().getSize(displaySize);
    mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, displaySize.x - 20, displaySize.y - 20, 50));
  }

Solution 2:

Try to store your marker on variables :

private Marker A;
private Marker B;

---

  A = mMap.addMarker(new MarkerOptions().position(a_local).title("a") 
            .snippet("xxx")
            .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker_yellow))).showInfoWindow();

   B = mMap.addMarker(new MarkerOptions().position(b_local).title("b")
            .snippet("yyy")
            .icon(BitmapDescriptorFactory.fromResource(R.drawable.markerb)))

---

Then create a timer that will call your load_locations_from_server() method and refresh the marker and update the camera in the response callback function :

publicvoidonResponse(JSONObject response) {

                    try {
                        JSONArrayjsonArray= response.getJSONArray("locations");

                        for (inti=0; i < jsonArray.length(); i++) {
                            JSONObjectrespons= jsonArray.getJSONObject(i);

                            a_lat=respons.getString("a_lat");
                            a_lon=respons.getString("a_lon");
                            b_lat=respons.getString("b_lat");
                            b_lon=respons.getString("b_lon");        

                            A.setLocation(LatLng(a_lat,a_lon));
                            B.setLocation(LatLng(b_lat,b_lon));

                            LatLngBounds.Builderbuilder=newLatLngBounds.Builder();
                            builder.include(A.getPosition());
                            builder.include(B.getPosition());
                            LatLngBoundsbounds= builder.build();
                            CameraUpdatecu= CameraUpdateFactory.newLatLngBounds(bounds, 0);
                            mMap..moveCamera(cu);
                        }

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