Get driving directions using Google Maps API v2

I am trying to get the driving direction between the two positions:

LatLng(12.917745600000000000,77.623788300000000000)
LatLng(12.842056800000000000,7.663096499999940000)

The code which i have tried:

Polyline line = mMap.addPolyline(new PolylineOptions().
    add(new LatLng(12.917745600000000000,77.623788300000000000),
    new LatLng(12.842056800000000000,7.663096499999940000))
       .width(5).color(Color.RED));

But this draws a straight line between the two points .

Is there any other method/way to get the driving directions between these two points.

I just release my latest library for Google Maps Direction API on Android https://github.com/akexorcist/Android-GoogleDirectionLibrary

This is what I am using,

Intent intent = new Intent(android.content.Intent.ACTION_VIEW, 
Uri.parse("http://maps.google.com/maps?saddr="+latitude_cur+","+longitude_cur+"&daddr="+latitude+","+longitude));
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addCategory(Intent.CATEGORY_LAUNCHER );     
intent.setClassName("com.google.android.apps.maps", "com.google.android.maps.MapsActivity");
startActivity(intent);

You can also try the following project that aims to help use that api. It's here:https://github.com/MathiasSeguy-Android2EE/GDirectionsApiUtils

How it works, definitly simply:

public class MainActivity extends ActionBarActivity implements DCACallBack{
/**
 * Get the Google Direction between mDevice location and the touched location using the     Walk
 * @param point
 */
private void getDirections(LatLng point) {
     GDirectionsApiUtils.getDirection(this, mDeviceLatlong, point,     GDirectionsApiUtils.MODE_WALKING);
}

/*
 * The callback
 * When the direction is built from the google server and parsed, this method is called and give you the expected direction
 */
@Override
public void onDirectionLoaded(List<GDirection> directions) {        
    // Display the direction or use the DirectionsApiUtils
    for(GDirection direction:directions) {
        Log.e("MainActivity", "onDirectionLoaded : Draw GDirections Called with path " + directions);
        GDirectionsApiUtils.drawGDirection(direction, mMap);
    }
}