Directions.java

package com.mapexample.mapexample;

import java.io.InputStream;
import java.util.ArrayList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import com.google.android.maps.GeoPoint;

public class Directions {

  public static ArrayList<GeoPoint> getDirections(double lat1, double lon1,
			double lat2, double lon2) {
double lat,lng;
		String url = String.format("%s=%s,%s&destination=%s,%s%s",
				"http://maps.googleapis.com/maps/api/directions/xml?origin",
				lat1, lon1, lat2, lon2, "&sensor=false");
		String tag[] = { "lat", "lng" };
		ArrayList<GeoPoint> list_of_geopoints = new ArrayList<GeoPoint>();
		HttpResponse response = null;
		try {
			HttpClient httpClient = new DefaultHttpClient();
			HttpContext localContext = new BasicHttpContext();
			HttpPost httpPost = new HttpPost(url);
			response = httpClient.execute(httpPost, localContext);
			InputStream in = response.getEntity().getContent();
			DocumentBuilder builder = DocumentBuilderFactory.newInstance()
					.newDocumentBuilder();
			Document doc = builder.parse(in);
			if (doc != null) {
				NodeList nl1, nl2;
				nl1 = doc.getElementsByTagName(tag[0]);
				nl2 = doc.getElementsByTagName(tag[1]);
				list_of_geopoints.add(new GeoPoint((int) (lat1 * 1E6),
						(int) (lon1 * 1E6)));
				if (nl1.getLength() > 0) {
					list_of_geopoints = new ArrayList<GeoPoint>();
					for (int i = 0; i < nl1.getLength(); i++) {
						Node node1 = nl1.item(i);
						Node node2 = nl2.item(i);
						lat = Double.parseDouble(node1.getTextContent());
						  lng = Double.parseDouble(node2.getTextContent());
						list_of_geopoints.add(new GeoPoint((int) (lat * 1E6),
								(int) (lng * 1E6)));
					}
				} else {
					// No points found
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return list_of_geopoints;
	}
}

googlemap_native_MyMapActivity.java

void setupMapView() {
  	setContentView(R.layout.activity_main);
		mapView = (MapView) findViewById(R.id.mapview);
		mapView.setBuiltInZoomControls(true);
	}

	
	void drawRoute(double slat,double slon,double dlat,double dlon) {
		
		ArrayList<?> all_geo_points = Directions.getDirections(
				slat, slon, dlat,dlon );
		mapOverlays.add(new MyOverlay(all_geo_points));
		controller.setZoom(12);
		mapView.invalidate();
	}

		void drawLocation(GeoPoint current_location) {
		Drawable drawable = this.getResources().getDrawable(R.id.map_icon);
		OverlayItem overlayItem = new OverlayItem(current_location, "", "");
		itemizedOverlay = new MyItemizedOverlay(drawable, this);
		itemizedOverlay.addOverlay(overlayItem);
		mapView.getOverlays().add(itemizedOverlay);
		mapView.invalidate();
	}

	

MyItemizedOverlay.java

 package com.mapexample.mapexample;

import java.util.ArrayList;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.view.GestureDetector;
import android.view.MotionEvent;

import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapView;
import com.google.android.maps.OverlayItem;

public class MyItemizedOverlay extends ItemizedOverlay<OverlayItem> {

  
	private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();

	public MyItemizedOverlay(Drawable defaultMarker, Context ctx) {
		super(boundCenterBottom(defaultMarker));

	}

	public void addOverlay(OverlayItem overlay) {
		mOverlays.add(overlay);
		populate();
	}

	public void clear() {

		mOverlays.clear();
		populate();
	}

	@Override
	protected OverlayItem createItem(int i) {
		return mOverlays.get(i);
	}

	@Override
	public int size() {
		return mOverlays.size();
	}

	@Override
	protected boolean onTap(int index) {
		return true;
	}

	@Override
	public boolean onTouchEvent(MotionEvent event, MapView mapView) {

		return false;
	}

}

MyOverlay.java

public class MyOverlay1 extends Overlay {

  	private ArrayList all_geo_points;

		public MyOverlay1(ArrayList allGeoPoints) {
			super();
			this.all_geo_points = allGeoPoints;
		}

		@Override
		public boolean draw(Canvas canvas, MapView mv, boolean shadow, long when) {
			super.draw(canvas, mv, shadow);
			drawPath(mv, canvas);
			return true;
		}

		public void drawPath(MapView mv, Canvas canvas) {
			int xPrev = -1, yPrev = -1, xNow = -1, yNow = -1;
			Paint paint = new Paint();
			paint.setColor(Color.BLUE);
			paint.setStyle(Paint.Style.FILL_AND_STROKE);
			paint.setStrokeWidth(4);
			paint.setAlpha(100);
			if (all_geo_points != null)
				for (int i = 0; i < all_geo_points.size() - 4; i++) {
					GeoPoint gp = (GeoPoint) all_geo_points.get(i);
					Point point = new Point();
					mv.getProjection().toPixels(gp, point);
					xNow = point.x;
					yNow = point.y;
					if (xPrev != -1) {
						canvas.drawLine(xPrev, yPrev, xNow, yNow, paint);
					}
					xPrev = xNow;
					yPrev = yNow;
				}
		}
	}