OverlayItem not updating on location change (OSM)

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.

You are not changing the position of the icon when you change location. You will have to do this in onLocationChanged. This means you'll have to make the GestureListener a non anonynmous class, i.e. give it a name as you'll need to refer to it again. I'll post some modified code. — NickT, Jul 02 '11 at 16:59

score 4 · Accepted Answer · answered Jul 02 '11 at 17:07

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)

I know I had to modify the onLocationChanged method. but what is the purpose of the Glistener? — rayman, Jul 03 '11 at 06:41
The code in it was already there as an anonymous class, which is one that has no name and is defined and instantiated in a single step. Because we want to instantiate it twice now, we need to move the code to an inner class code block and give it a name (Glistener) so we can refer to it with the 'new Glistener()' expression. — NickT, Jul 03 '11 at 06:58
I know what inner class is. but why did you need to use Glistener in order to "validate" the Icon place within the new coordinates? sorry for the misunderstanding. — rayman, Jul 03 '11 at 07:07
If you add more and more icons as you change location and don't pass a new Glistener to the overlay in onLocationChanged(), then the app will crash with an index out of bounds error. Try it. I have to go out now, good luck with it all. — NickT, Jul 03 '11 at 07:17
In the case of have more than one overlay, is possible clean one without the others? — Maske, Aug 21 '20 at 18:15

OverlayItem not updating on location change (OSM)

1 Answers1