title: Osmdroid marker not updating
body: <p>I have to make implement navigation using osmdriod maps api. The Activity receives broadcasts from a location service, using following receiver:</p>
  
  <pre><code>public class ReceiveMessages extends BroadcastReceiver
  {
  
      @Override
      public void onReceive(Context context, Intent intent)
      {
          String lat = intent.getStringExtra("Latitude");
          String lon = intent.getStringExtra("Longitude");
          System.out.println("on recieve called "+lat+lon);
          updateUi(Double.parseDouble(lat),Double.parseDouble(lon));
      }
  }
  </code></pre>
  
  <p>Following is updateUi method:</p>
  
  <pre><code>public void updateUi(Double lat,Double lon) { 
      gPt1 = new GeoPoint(lat, lon);
      Marker endMarker = new Marker(mMapView);
      endMarker.setPosition(gPt1);
      endMarker.setTitle("Current Position"+lat+" "+lon);
      mMapView.getOverlays().add(endMarker);
  
      Polyline pl = new Polyline();
      pl.setWidth(5f);
      pl.setColor(Color.RED);
      List&lt;GeoPoint&gt; pts = new ArrayList&lt;&gt;();
      pts.add(gPt0);
      pts.add(gPt1);
      pl.setPoints(pts);
      pl.setGeodesic(true);
      mMapView.getOverlayManager().add(pl);
      mMapView.invalidate();
  }
  </code></pre>
  
  <p>Now what is happening is that the current position markers are getting added one above the other as and when broadcast receiver gets called when current position changes like <a href="https://drive.google.com/file/d/0ByknFXX0Jq-QQ1BrZUxrM1NaTGVqb2t6Mll3RmxpMmdsXzBB/view?usp=sharing" rel="nofollow">here</a>, <a href="https://drive.google.com/file/d/0ByknFXX0Jq-QNkI2dGxQU21iM1BvMTJacEZzZU1HNXJmQ18w/view?usp=sharing" rel="nofollow">here</a>. </p>
  
  <p>I just want a single current position marker and a single poly line should be present between the 2 markers, which get updated.</p>