Question

I have been using a previous question and a Google Tutorial to attempt to add multiple pin images on a Google Map view when the current location of the user changes.

Each pin when tapped displays the Longitude and Latitude of the pin.

However currently my code only displays one pin and does not add another image when the location of the user changes. I am relatively new to Android and can’t see why this code wouldn’t work?

Map.java:

import java.util.List;

import android.graphics.drawable.Drawable;
import android.os.Bundle;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.MyLocationOverlay;
import com.google.android.maps.OverlayItem;

import android.util.Log;


public class Map extends MapActivity {
   private MapView map;
   private MapController controller;
   private double lon, lat;
   private Drawable drawable;
   private MapOverlay itemizedoverlay;
   private List<Overlay> mapOverlays;

   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);

      setContentView(R.layout.maps);
      initMapView();
      mapOverlays = map.getOverlays();
      drawable = this.getResources().getDrawable(R.drawable.pin);
      itemizedoverlay = new MapOverlay(drawable, this);
      initMyLocation();

   }





   private void initMapView() {
      map = (MapView) findViewById(R.id.map);
      controller = map.getController();
      map.setSatellite(true);
      map.setBuiltInZoomControls(true);
   }


   private void initMyLocation() {
      final MyLocationOverlay overlay = new MyLocationOverlay(this, map);
      overlay.enableMyLocation();
      overlay.enableCompass(); // wont work in emulator
      overlay.runOnFirstFix(new Runnable() {
         public void run() {
            // Zoom in to current location - 1 is word view
            controller.setZoom(20);
            controller.animateTo(overlay.getMyLocation());
            lon = overlay.getMyLocation().getLongitudeE6();

            lat = overlay.getMyLocation().getLatitudeE6();
            setLON(lon);
            setLAT(lat);
            //-0.959896
            //51.742953
            Log.w("test-lon", Double.toString(lon/1E6));
            Log.w("test-lat", Double.toString(lat/1E6));
            GeoPoint point = new GeoPoint((int)(lat),(int)(lon));

            mapOverlays.add(itemizedoverlay);
            test(point);
         }
      });





      map.getOverlays().add(overlay);

   }

   public void setLON(double x){ //remove?

       lon = x;

   }
 public void setLAT(double x){ //remove?

       lat = x;
   }
   public void test(GeoPoint px){

       OverlayItem overlayitem = new OverlayItem(px,"Test Point" , "Lat: " + Double.toString(lat/1E6) + "\nLon: " + Double.toString(lon/1E6) );
       itemizedoverlay.addOverlay(overlayitem);


   }


   @Override
   protected boolean isRouteDisplayed() {
      // Required method from MapActivity


      return false;
   }
}

MapOverlay.java:

import java.util.ArrayList;

import android.app.AlertDialog;
import android.content.Context;
import android.graphics.drawable.Drawable;

import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.OverlayItem;

public class MapOverlay extends ItemizedOverlay {

    private ArrayList<OverlayItem> mapOverlay = new ArrayList<OverlayItem>();
    private Context mContext;

    public MapOverlay (Drawable defaultMarker, Context context) {
          super(boundCenterBottom(defaultMarker));
          mContext = context;
        }

    public MapOverlay(Drawable arg0) {
        super(boundCenterBottom(arg0));

    }


    public void addOverlay(OverlayItem overlay) {
        mapOverlay.add(overlay);
        populate();
    }

    @Override
    protected OverlayItem createItem(int i) {
      return mapOverlay.get(i);
    }

    @Override
    public int size() {
        return mapOverlay.size();
    }


    @Override
    protected boolean onTap(int index) {
      OverlayItem item = mapOverlay.get(index);
      AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
      dialog.setTitle(item.getTitle());
      dialog.setMessage(item.getSnippet());
      dialog.show();
      return true;
    }

}

Answer 1

u need implements class LocationListener for listen our location changes and update on the map.

class LocationsListeners implements LocationListener {

    @Override
    public void onLocationChanged(Location location) {
        setLAT(location.getLatitude());
        setLON(location.getLongitude());
        setGeoPoint(lat, lon);
        mapOverlays.add(geoPoint);          
    }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }

}

u need method for calc the GeoPoint:

    public GeoPoint setGeoPoint(double lat, double lon){
       geoPoint = new GeoPoint((int) (lat * 1E6), (int)(lon  * 1E6));
       return geoPoint;
    }

or using Little Fluffy Location – Its library that updates our location and notify u, is broadcast receiver, very simple and fast implementation:

try:

http://code.google.com/p/little-fluffy-location-library/