Add Scale Bar on OpenStreetMap

To add a scale bar on OpenStreetMapView is very easy:
- New a ScaleBarOverlay object
- add the Overlay to the MapView

ScaleBarOverlay myScaleBarOverlay = new ScaleBarOverlay(this);
myOpenMapView.getOverlays().add(myScaleBarOverlay);

Modify main Java code AndroidOpenStreetMapViewActivity.java from last exercise "Update location on OpenStreetMap".

package com.exercise.OpenStreetMapView;

import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapController;
import org.osmdroid.views.MapView;
import org.osmdroid.views.overlay.ScaleBarOverlay;

import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;

public class AndroidOpenStreetMapViewActivity extends Activity {
 
 private MapView myOpenMapView;
 private MapController myMapController;
 
 LocationManager locationManager;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        myOpenMapView = (MapView)findViewById(R.id.openmapview);
        myOpenMapView.setBuiltInZoomControls(true);
        myMapController = myOpenMapView.getController();
        myMapController.setZoom(12);
        
        locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        
        //for demo, getLastKnownLocation from GPS only, not from NETWORK
        Location lastLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if(lastLocation != null){
         updateLoc(lastLocation);
        }
        
        //Add Scale Bar
        ScaleBarOverlay myScaleBarOverlay = new ScaleBarOverlay(this);
        myOpenMapView.getOverlays().add(myScaleBarOverlay);
    }
    
    @Override
 protected void onResume() {
  // TODO Auto-generated method stub
  super.onResume();
  locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, myLocationListener);
  locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, myLocationListener);
 }

 @Override
 protected void onPause() {
  // TODO Auto-generated method stub
  super.onPause();
  locationManager.removeUpdates(myLocationListener);
 }

 private void updateLoc(Location loc){
     GeoPoint locGeoPoint = new GeoPoint(loc.getLatitude(), loc.getLongitude());
     myMapController.setCenter(locGeoPoint);
     myOpenMapView.invalidate();
    }
    
    private LocationListener myLocationListener
    = new LocationListener(){

  @Override
  public void onLocationChanged(Location location) {
   // TODO Auto-generated method stub
   updateLoc(location);
  }

  @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
   
  }
     
    };

}