Question

I am using OSMdroid.

I have managed thanks to this post Adding Overlay to OSMDROID to creata overlay static item on a specific location.

now I am trying to make the map little bit more dynamic. so when the location change the OverLayItem (which marking the specific location on the map) will update itself also.

this is what I tried to do. the map does update but the OverLayItem doesnt.

code:

package com.test.overlay;

import java.util.ArrayList;
import org.osmdroid.DefaultResourceProxyImpl;
import org.osmdroid.ResourceProxy;
import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapController;
import org.osmdroid.views.MapView;
import org.osmdroid.views.overlay.ItemizedIconOverlay;
import org.osmdroid.views.overlay.ItemizedOverlay;
import org.osmdroid.views.overlay.OverlayItem;
import org.osmdroid.views.util.constants.MapViewConstants;

import android.app.Activity;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;

public class SampleWithMinimapItemizedoverlay extends Activity implements
        LocationListener, MapViewConstants
{

    private MapView mMapView;
    private MapController mapController;
    private LocationManager mLocMgr;
    private ItemizedOverlay<OverlayItem> mMyLocationOverlay;
    private ResourceProxy mResourceProxy;
    int longtitude = 31987968;
    int latitude = 34783155;

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

        mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());
        setContentView(R.layout.main);

        mMapView = (MapView) this.findViewById(R.id.mapview);
        mMapView.setTileSource(TileSourceFactory.MAPNIK);
        mMapView.setBuiltInZoomControls(true);
        mMapView.setMultiTouchControls(true);
        mapController = this.mMapView.getController();
        mapController.setZoom(15);
        GeoPoint point2 = new GeoPoint(longtitude, latitude); // centre map here
        GeoPoint point3 = new GeoPoint(longtitude + 2000, latitude + 2000); // icon
                                                                            // goes
                                                                            // here
        // 31.987968,34.783155

        mapController.setCenter(point2);
        mLocMgr = (LocationManager) getSystemService(LOCATION_SERVICE);
        mLocMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 100,
                this);

        ArrayList<OverlayItem> items = new ArrayList<OverlayItem>();
        // Put overlay icon a little way from map centre
        items.add(new OverlayItem("Here", "SampleDescription", point3));

        /* OnTapListener for the Markers, shows a simple Toast. */
        this.mMyLocationOverlay = new ItemizedIconOverlay<OverlayItem>(items,
                new ItemizedIconOverlay.OnItemGestureListener<OverlayItem>()
                {
                    @Override
                    public boolean onItemSingleTapUp(final int index,
                            final OverlayItem item)
                    {
                        Toast.makeText(SampleWithMinimapItemizedoverlay.this,
                                "Item '" + item.mTitle, Toast.LENGTH_LONG)
                                .show();
                        return true; // We 'handled' this event.
                    }

                    @Override
                    public boolean onItemLongPress(final int index,
                            final OverlayItem item)
                    {
                        Toast.makeText(SampleWithMinimapItemizedoverlay.this,
                                "Item '" + item.mTitle, Toast.LENGTH_LONG)
                                .show();
                        return false;
                    }
                }, mResourceProxy);
        this.mMapView.getOverlays().add(this.mMyLocationOverlay);
        mMapView.invalidate();
    }

    -------//here I tried to do the change !!!!!!!!!---------------
    -- The map location being updated but not the overlayItem.
    public void onLocationChanged(Location location)
    {
        latitude = (int) (location.getLatitude() * 1E6);
        longtitude = (int) (location.getLongitude() * 1E6);
        Toast.makeText(SampleWithMinimapItemizedoverlay.this,
                "Location changed. Lat:" + latitude + " long:" + longtitude ,
                Toast.LENGTH_LONG).show();
        GeoPoint gpt = new GeoPoint(latitude, longtitude);
        mapController.setCenter(gpt);
        mMapView.invalidate();
    }

    @Override
    public void onProviderDisabled(String arg0)
    {
    }

    @Override
    public void onProviderEnabled(String provider)
    {
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras)
    {
    }

}

Thanks,

ray.

Answer 1

This should work OK

.

public class SampleWithMinimapItemizedoverlay extends Activity implements
        LocationListener, MapViewConstants {

    private MapView mMapView;
    private MapController mapController;
    private LocationManager mLocMgr;
    private ItemizedOverlay<OverlayItem> mMyLocationOverlay;
    private ResourceProxy mResourceProxy;
    int mLongtitude = 31987968;
    int mLatitude = 34783155;
    ArrayList<OverlayItem> mItems;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());
        setContentView(R.layout.main);

        mMapView = (MapView) this.findViewById(R.id.mapview);
        mMapView.setTileSource(TileSourceFactory.MAPNIK);
        mMapView.setBuiltInZoomControls(true);
        mMapView.setMultiTouchControls(true);
        mapController = this.mMapView.getController();
        mapController.setZoom(15);
        GeoPoint point2 = new GeoPoint(mLongtitude, mLatitude); // centre map here
        GeoPoint point3 = new GeoPoint(mLongtitude + 2000, mLatitude + 2000); // icon
                                                                            // goes
        // 31.987968,34.783155
        mapController.setCenter(point2);
        mLocMgr = (LocationManager) getSystemService(LOCATION_SERVICE);
        mLocMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 100,
                this);

        mItems = new ArrayList<OverlayItem>();
        // Put overlay icon a little way from map centre
        mItems.add(new OverlayItem("Here", "SampleDescription", point3));

        /* OnTapListener for the Markers, shows a simple Toast. */
        // REFER TO THE GESTURE LISTEMER BY NAME NOW
        this.mMyLocationOverlay = new ItemizedIconOverlay<OverlayItem>(mItems,
                new Glistener() , mResourceProxy);
        this.mMapView.getOverlays().add(this.mMyLocationOverlay);
        mMapView.invalidate();
    }

    //We can't use an anonymous class anymore if we want to change the position
    // of the overlays/icons when location changed, give it a name
    class Glistener implements OnItemGestureListener<OverlayItem> {
        @Override
        public boolean onItemLongPress(int index, OverlayItem item) {
            Toast.makeText(SampleWithMinimapItemizedoverlay.this, "Item " + item.mTitle,
                    Toast.LENGTH_LONG).show();

            return false;
        }

        @Override
        public boolean onItemSingleTapUp(int index, OverlayItem item) {
            Toast.makeText(SampleWithMinimapItemizedoverlay.this, "Item " + item.mTitle,
                    Toast.LENGTH_LONG).show();
            return true; // We 'handled' this event.

        }

    }
    // -------//here I tried to do the change !!!!!!!!!---------------
    // -- The map location being updated but not the overlayItem.
    public void onLocationChanged(Location location) {
        mLatitude = (int) (location.getLatitude() * 1E6);
        mLongtitude = (int) (location.getLongitude() * 1E6);
        Toast.makeText(SampleWithMinimapItemizedoverlay.this,
                "Location changed. Lat:" + mLatitude + " long:" + mLongtitude,
                Toast.LENGTH_LONG).show();
        GeoPoint gpt = new GeoPoint(mLatitude, mLongtitude);
        mapController.setCenter(gpt);
        mItems.clear(); // COMMENT OUT THIS LINE IF YOU WANT A NEW ICON FOR EACH CHANGE OF POSITION
        mItems.add(new OverlayItem("New", "SampleDescription", gpt));
        // Change the overlay
        this.mMyLocationOverlay = new ItemizedIconOverlay<OverlayItem>(mItems,
                new Glistener() , mResourceProxy);
        this.mMapView.getOverlays().clear();
        this.mMapView.getOverlays().add(this.mMyLocationOverlay);
        mMapView.invalidate();
    }

    @Override
    public void onProviderDisabled(String arg0) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    }

}

Just comment/uncomment the mItems.clear(); line depending on whether you want a new marker each time you change position. (The icon appears atthe position that you have moved to)