How to draw route in google-maps-api-v2 from my Current-location to a given Destination

MainActivity.java

public class MainActivity extends FragmentActivity { // Activity {

private static final String TAG ="MainActivity";
GoogleMap mMap;
GMapV2Direction md;

 LatLng fromPosition = new LatLng(12.914788 , 77.610106);
 LatLng toPosition = new LatLng(12.94231 , 77.59739);

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

md = new GMapV2Direction();
mMap = ((SupportMapFragment)getSupportFragmentManager()
.findFragmentById(R.id.the_map)).getMap();

LatLng coordinates = new LatLng(12.914788 , 77.610106);

mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.getUiSettings().setCompassEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
mMap.getUiSettings().setAllGesturesEnabled(true);
mMap.setTrafficEnabled(true);
mMap.animateCamera(CameraUpdateFactory.zoomTo(12));
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(coordinates, 16));

mMap.addMarker(new MarkerOptions().position(fromPosition).title("Start"));
mMap.addMarker(new MarkerOptions().position(toPosition).title("End"));

new showRoute().execute();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

private class showRoute extends AsyncTask<Void, Void, Document>{

Document doc;
PolylineOptions rectLine;

@Override
protected Document doInBackground(Void... params) {

doc = md.getDocument(fromPosition, toPosition, GMapV2Direction.MODE_DRIVING);

ArrayList<LatLng> directionPoint = md.getDirection(doc);
rectLine = new PolylineOptions().width(3).color(Color.RED);

for(int i = 0 ; i < directionPoint.size() ; i++) {
           rectLine.add(directionPoint.get(i));
}

return null;
}

@Override
protected void onPostExecute(Document result) {

mMap.addPolyline(rectLine);
}

}
}

------------------------------------------------------------------------------------------------
GMapV2Direction.java
package com.prabhakar;

public class GMapV2Direction {

public final static String MODE_DRIVING = "driving";
public final static String MODE_WALKING = "walking";

public GMapV2Direction() { }

public Document getDocument(LatLng start, LatLng end, String mode) {

//Implement THREADING concept here  ###

String url = "http://maps.googleapis.com/maps/api/directions/xml?"
+ "origin=" + start.latitude + "," + start.longitude
+ "&destination=" + end.latitude + "," + end.longitude
+ "&sensor=false&units=metric&mode=driving";

try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url);
HttpResponse response = httpClient.execute(httpPost, localContext);

InputStream in = response.getEntity().getContent();
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = builder.parse(in);
return doc;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

public String getDurationText (Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
        Node node1 = nl1.item(0);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "text"));
        Log.i("DurationText", node2.getTextContent());
return node2.getTextContent();
}

public int getDurationValue (Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
        Node node1 = nl1.item(0);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "value"));
        Log.i("DurationValue", node2.getTextContent());
return Integer.parseInt(node2.getTextContent());
}

public String getDistanceText (Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
        Node node1 = nl1.item(0);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "text"));
        Log.i("DistanceText", node2.getTextContent());
return node2.getTextContent();
}

public int getDistanceValue (Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
        Node node1 = nl1.item(0);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "value"));
        Log.i("DistanceValue", node2.getTextContent());
return Integer.parseInt(node2.getTextContent());
}

public String getStartAddress (Document doc) {
NodeList nl1 = doc.getElementsByTagName("start_address");
        Node node1 = nl1.item(0);
        Log.i("StartAddress", node1.getTextContent());
return node1.getTextContent();
}

public String getEndAddress (Document doc) {
NodeList nl1 = doc.getElementsByTagName("end_address");
        Node node1 = nl1.item(0);
        Log.i("StartAddress", node1.getTextContent());
return node1.getTextContent();
}

public String getCopyRights (Document doc) {
NodeList nl1 = doc.getElementsByTagName("copyrights");
        Node node1 = nl1.item(0);
        Log.i("CopyRights", node1.getTextContent());
return node1.getTextContent();
}

public ArrayList<LatLng> getDirection (Document doc) {
NodeList nl1, nl2, nl3;
        ArrayList<LatLng> listGeopoints = new ArrayList<LatLng>();
        nl1 = doc.getElementsByTagName("step");   
        if (nl1.getLength() > 0) {
            for (int i = 0; i < nl1.getLength(); i++) {
                Node node1 = nl1.item(i);
                nl2 = node1.getChildNodes();

                Node locationNode = nl2.item(getNodeIndex(nl2, "start_location"));
                nl3 = locationNode.getChildNodes();
                Node latNode = nl3.item(getNodeIndex(nl3, "lat"));
                double lat = Double.parseDouble(latNode.getTextContent());
                Node lngNode = nl3.item(getNodeIndex(nl3, "lng"));
                double lng = Double.parseDouble(lngNode.getTextContent());
                listGeopoints.add(new LatLng(lat, lng));

                locationNode = nl2.item(getNodeIndex(nl2, "polyline"));
                nl3 = locationNode.getChildNodes();
                latNode = nl3.item(getNodeIndex(nl3, "points"));
                ArrayList<LatLng> arr = decodePoly(latNode.getTextContent());
                for(int j = 0 ; j < arr.size() ; j++) {
                listGeopoints.add(new LatLng(arr.get(j).latitude, arr.get(j).longitude));
                }

                locationNode = nl2.item(getNodeIndex(nl2, "end_location"));
                nl3 = locationNode.getChildNodes();
                latNode = nl3.item(getNodeIndex(nl3, "lat"));
                lat = Double.parseDouble(latNode.getTextContent());
                lngNode = nl3.item(getNodeIndex(nl3, "lng"));
                lng = Double.parseDouble(lngNode.getTextContent());
                listGeopoints.add(new LatLng(lat, lng));
            }
        }
     
        return listGeopoints;
}

private int getNodeIndex(NodeList nl, String nodename) {
for(int i = 0 ; i < nl.getLength() ; i++) {
if(nl.item(i).getNodeName().equals(nodename))
return i;
}
return -1;
}

private ArrayList<LatLng> decodePoly(String encoded) {
ArrayList<LatLng> poly = new ArrayList<LatLng>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;

LatLng position = new LatLng((double) lat / 1E5, (double) lng / 1E5);
poly.add(position);
}
return poly;
}
}
--------------------------------------------------------------------------------------------------
main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"  >

    <fragment
        android:id="@+id/the_map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        class="com.google.android.gms.maps.SupportMapFragment"/>


</RelativeLayout>
--------------------------------------------------------------------------------------------------

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.prabhakar"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8"

        android:targetSdkVersion="17" />

  <permission android:name="com.prabhakar.permission.MAPS_RECEIVE"

         android:protectionLevel="signature"/>

    <uses-permission android:name="com.prabhakar.permission.MAPS_RECEIVE" />    

    <uses-permission android:name="android.permission.INTERNET" />

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    

    <uses-feature android:glEsVersion="0x00020000"

        android:required="true"/>

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme"

        android:debuggable="true" >

        

      <meta-data android:name="com.google.android.maps.v2.API_KEY"

            android:value="-----enter your v2 API key here----------"/>

        <activity

            android:name=".MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

    </application>

</manifest>

-----------------------------------------------------------------------------------------------