Question

I am working on an android application that determines user location in osm maps. I am being able to show user location on the map, but if the location change the whole map is reloaded, what’s wrong with that? Also how I can increase the accuracy of the user location? And how can I make a circle that increase and decrease according to the accuracy(as shown in Google one)?

code :

public class OsmDemoActivity extends Activity implements LocationListener, 
    MapViewConstants 
{  
private MapView mMapView; 
private MapController mapController; 
private LocationManager mLocMgr; 
private ItemizedOverlay<OverlayItem> mMyLocationOverlay; 
private ResourceProxy mResourceProxy; 

ArrayList<OverlayItem> items;

@Override 
public void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext()); 
    setContentView(R.layout.main); 
    //mMapView.setUseDataConnection(false);
    initilaizeMap();
    //addOverlay(); 
    mLocMgr = (LocationManager) getSystemService(LOCATION_SERVICE); 
    mLocMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);      
} 

public void initilaizeMap()
{
    mMapView = (MapView) this.findViewById(R.id.mapView); 
    mMapView.setTileSource(TileSourceFactory.MAPNIK); 



    //mMapView.setUseDataConnection(false);



    mMapView.setBuiltInZoomControls(true); 
    mMapView.setMultiTouchControls(true); 
    mapController = this.mMapView.getController(); 
    mapController.setZoom(15); 
    mapController.setCenter(new GeoPoint(15.610762,32.540345));


    /*
    final MyLocationOverlay myLocationOverlay = new MyLocationOverlay(this, mMapView, 
            mResourceProxy); 
    myLocationOverlay.enableMyLocation();
    //myLocationOverlay.disableMyLocation(); // not on by default 
    myLocationOverlay.disableCompass(); 
    myLocationOverlay.disableFollowLocation(); 
    myLocationOverlay.setDrawAccuracyEnabled(true); 
    myLocationOverlay.runOnFirstFix(new Runnable() { 
        public void run() { 
            mapController.animateTo(myLocationOverlay 
                    .getMyLocation()); 
        } 
    }); 
    //ArrayList<OverlayItem> mOsmOverlays;
    //mOsmOverlays.add(myLocationOverlay); 
    */
}

public void addOverlay()
{
    GeoPoint point2 = new GeoPoint(53554070, -2959520); // centre map here 
    GeoPoint point3 = new GeoPoint(53554070 + 1000, -2959520 + 1000); // icon goes here 
    GeoPoint point4 = new GeoPoint(15.610844, 32.540045);
    GeoPoint point5 = new GeoPoint(15610844 + 40, 32540045 + 40);
    GeoPoint point6 = new GeoPoint(15610844 + 50, 32540045 + 50);
    GeoPoint point7 = new GeoPoint(15610844 + 10, 32540045 +10);
    mapController.setCenter(point4);
    items = new ArrayList<OverlayItem>(); 
    // Put overlay icon a little way from map center 
    items.add(new OverlayItem("Here5", "SampleDescription", point5)); 
    items.add(new OverlayItem("Here6", "SampleDescription", point6));
    items.add(new OverlayItem("Here7", "SampleDescription", point7));
    /* 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( 
                            OsmDemoActivity.this, 
                            "Item onItemSingleTapUp '" + item.mTitle, Toast.LENGTH_LONG).show(); 
                    return true; // We 'handled' this event. 
                } 
                @Override 
                public boolean onItemLongPress(final int index, 
                        final OverlayItem item) { 
                    Toast.makeText( 
                            OsmDemoActivity.this,  
                            "Item onItemLongPress '" + item.mTitle ,Toast.LENGTH_LONG).show(); 
                    return false; 
                } 
            }, mResourceProxy); 
    this.mMapView.getOverlays().add(this.mMyLocationOverlay); 
    mMapView.invalidate(); 
}

public void displayLocation(GeoPoint loc)
{
    mapController.setCenter(loc);
    items = new ArrayList<OverlayItem>(); 
    // Put overlay icon a little way from map center
    items.add(new OverlayItem("Here u r", "SampleDescription", loc));
    /* 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( 
                            OsmDemoActivity.this, 
                            "Item onItemSingleTapUp '" + item.mTitle, Toast.LENGTH_LONG).show(); 
                    return true; // We 'handled' this event. 
                } 
                @Override 
                public boolean onItemLongPress(final int index, 
                        final OverlayItem item) { 
                    Toast.makeText( 
                            OsmDemoActivity.this,  
                            "Item onItemLongPress '" + item.mTitle ,Toast.LENGTH_LONG).show(); 
                    return false; 
                } 
            }, mResourceProxy); 
    mMapView.getOverlays().clear();
    this.mMapView.getOverlays().add(this.mMyLocationOverlay); 
    //mMapView.invalidate();
}

public void onLocationChanged(Location location)
{ 
    int lat = (int) (location.getLatitude() * 1E6); 
    int lng = (int) (location.getLongitude() * 1E6); 
    GeoPoint gpt = new GeoPoint(lat, lng); 
    //mapController.setCenter(gpt); 
    //mMapView.invalidate();
    displayLocation(gpt);
} 

    @Override 
    public void onProviderDisabled(String arg0) {} 
    @Override 
    public void onProviderEnabled(String provider) {} 
    @Override 
    public void onStatusChanged(String provider, int status, Bundle extras) {} 

}

Answer 1

You must use an location change listener
Maybe this can help you

Listener:

package dispatch.driver.osmMaps;

import org.osmdroid.util.GeoPoint;

import android.location.Location;
import android.location.LocationListener;
import android.os.Bundle;
import android.widget.Toast;

public class OsmGeoUpdateHandler implements LocationListener
{

    private OsmMapsActivity mMapActivity;

    public OsmGeoUpdateHandler(OsmMapsActivity aMapActivity)
    {
        this.mMapActivity = aMapActivity;

    }

    @Override
    public void onLocationChanged(Location location)
    {
        Toast.makeText(mMapActivity,
                "latitude = " + location.getLatitude() * 1e6 + " longitude = " + location.getLongitude() * 1e6,
                Toast.LENGTH_SHORT).show();

        int latitude = (int) (location.getLatitude() * 1E6);
        int longitude = (int) (location.getLongitude() * 1E6);
        GeoPoint point = new GeoPoint(latitude, longitude);
        mMapActivity.updateCarPosition(point);
    }

    @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

    }

}

OsmMapActivity class (how to use listener)

public class OsmMapsActivity extends Activity
{
    // final private int MAP_DEFAULT_ZOOM = 14;
    final private double MAP_DEFAULT_LATITUDE = 44.445883;
    final private double MAP_DEFAULT_LONGITUDE = 26.040963;

    private MapView mMapView;
    private ResourceProxy mResourceProxy;
    private OsmMapsItemizedOverlay mItemizedOverlay;
    private MyLocationOverlay mMyLocationOverlay;
    private LocationManager locationManager;
    private OverlayItem lastPosition = null;
    private Order mOrder;
    OsmGeoUpdateHandler mUpdateHandler;
    private ArrayList<OverlayItem> mItems = new ArrayList<OverlayItem>();

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

        // Specify the XML layout to use:
        setContentView(R.layout.osmmap);

        mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());
        mMapView = (MapView) findViewById(R.id.mapview);

        // Setup the mapView controller:
        mMapView.setBuiltInZoomControls(true);
        mMapView.setMultiTouchControls(true);
        mMapView.setClickable(true);
        mMapView.setUseDataConnection(false);
        mMapView.setTileSource(TileSourceFactory.MAPNIK);
        mMapView.getController().setZoom(12);


        /* location manager */
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        mUpdateHandler = new OsmGeoUpdateHandler(this);
        Location location = null;

        for (String provider : locationManager.getProviders(true))
        {
            location = locationManager.getLastKnownLocation(provider);
            if (location != null)
            {
                //location.setLatitude(MAP_DEFAULT_LATITUDE);
                //location.setLongitude(MAP_DEFAULT_LONGITUDE);
                locationManager.requestLocationUpdates(provider, 0, 0, mUpdateHandler);
                break;
            }
        }

        //add car position
        if (location == null)
        {
            location = new Location(LocationManager.GPS_PROVIDER);
            location.setLatitude(MAP_DEFAULT_LATITUDE);
            location.setLongitude(MAP_DEFAULT_LONGITUDE);
            updateCarPosition(new GeoPoint(location));
        }

    } // end onCreate()
public void updateCarPosition(GeoPoint aPoint)
    {
        if (mItemizedOverlay == null)
        {
            return;
        }
        OverlayItem overlayItem;

        /* remove last position marker */
        removeLastPosition(lastPosition);

        overlayItem = new OverlayItem("Center", "Center", (GeoPoint) aPoint);

        lastPosition = overlayItem;

        mItemizedOverlay.addOverlay(overlayItem);


        mMapView.getOverlays().add(mItemizedOverlay);
        mMapView.getController().animateTo(aPoint);

    }
}