getting a bug at getResources() in android?

I want to set a marker at the starting point of map. but getResource is giving error, below is the code. please help. getResources() is used in the last, please see at bottom package infy.route;

public class MapRouteActivity extends MapActivity {


    MapView mapView;
    private Road mRoad;


    @Override
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.routeplanning);

            mapView = (MapView) findViewById(R.id.mapview);
            mapView.setBuiltInZoomControls(true);

            Bundle extras = this.getIntent().getExtras();
            String fLat=extras.getString("fromLat");
            String fLong=extras.getString("fromLong");
            String tLat=extras.getString("toLat");
            String tLong=extras.getString("toLong");

            final double fromLat=Double.parseDouble(fLat);
            final double fromLon=Double.parseDouble(fLong);
            final double toLat=Double.parseDouble(tLat);
            final double toLon=Double.parseDouble(tLong); 

      new Thread()
     {
                    @Override
                    public void run() 
                    {



                          //double fromLat = 28.6353, fromLon = 77.2250, toLat = 30.7313, toLon = 76.7754;
                            /***url contains the path to fetch the kml file from the internet*/
                            String url = RoadProvider
                                            .getUrl(fromLat, fromLon, toLat, toLon);
                            InputStream is = getConnection(url);
                            mRoad = RoadProvider.getRoute(is);
                            mHandler.sendEmptyMessage(0);
                    }
            }.start();
    }

    Handler mHandler = new Handler()
    {
            public void handleMessage(android.os.Message msg)
            {
                    TextView textView = (TextView) findViewById(R.id.description);
                    textView.setText(mRoad.mName + " " + mRoad.mDescription);
                    MapOverlay mapOverlay = new MapOverlay(mRoad, mapView);
                    List<Overlay> listOfOverlays = mapView.getOverlays();
                    listOfOverlays.clear();
                    listOfOverlays.add(mapOverlay);
                    mapView.invalidate();
            };
    };

    private InputStream getConnection(String url) {
            InputStream is = null;
            try {
                    //Opens a connection to the remote database(bidirectional)
                    URLConnection conn = new URL(url).openConnection();
                    is = conn.getInputStream();
            } catch (MalformedURLException e) {
                    e.printStackTrace();
            } catch (IOException e) {
                    e.printStackTrace();
            }
            return is;
    }

    @Override
    protected boolean isRouteDisplayed() {
            return false;
    }
}

class MapOverlay extends com.google.android.maps.Overlay {
    Road mRoad;
    ArrayList<GeoPoint> mPoints;
    Drawable greenMarker;
    Drawable finishMarker;
    HelloItemizedOverlay itemizedOverlay;
    List<Overlay> mapOverlays;
    LinearLayout linearLayout;


    public MapOverlay(Road road, MapView mv) {
            mRoad = road;

            if (road.mRoute.length > 0)
            {
                    mPoints = new ArrayList<GeoPoint>();
                    for (int i = 0; i < road.mRoute.length; i++)
                    {

                            mPoints.add(new GeoPoint((int) (road.mRoute[i][1] * 1000000),
                                            (int) (road.mRoute[i][0] * 1000000)));

                    }
                    int moveToLat = (mPoints.get(0).getLatitudeE6() + (mPoints.get(
                                    mPoints.size() - 1).getLatitudeE6() - mPoints.get(0)
                                    .getLatitudeE6()) / 2);
                    int moveToLong = (mPoints.get(0).getLongitudeE6() + (mPoints.get(
                                    mPoints.size() - 1).getLongitudeE6() - mPoints.get(0)
                                    .getLongitudeE6()) / 2);
                    GeoPoint moveTo = new GeoPoint(moveToLat, moveToLong);

                    MapController mapController = mv.getController();
                    mapController.animateTo(moveTo);
                    mapController.setZoom(7);
            }
    }

    @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) {

        greenMarker = getResources().getDrawable(R.drawable.greenmarker);

            int x1 = -1, y1 = -1, x2 = -1, y2 = -1;
            Paint paint = new Paint();
            paint.setColor(Color.GREEN);
            paint.setStyle(Paint.Style.STROKE);
            paint.setStrokeWidth(3);
            mapOverlays = mv.getOverlays();
            itemizedOverlay = new HelloItemizedOverlay(greenMarker);

            for (int i = 0; i < mPoints.size(); i++) {
                    Point point = new Point();
                    mv.getProjection().toPixels(mPoints.get(i), point);
                    if(i == 0){
                        OverlayItem overlayitem = new OverlayItem(mPoints.get(0), "", "");
                        itemizedOverlay.addOverlay(overlayitem);
                        mapOverlays.add(itemizedOverlay);      
                    }
                    x2 = point.x;
                    y2 = point.y;
                    if (i > 0) {
                            canvas.drawLine(x1, y1, x2, y2, paint);
                    }
                    x1 = x2;
                    y1 = y2;
            }
    }





}

Here is the stacktrace at line 174 i used getResource() and 168 calling of drawpath() is done

02-23 23:20:20.960: ERROR/AndroidRuntime(804): java.lang.NullPointerException
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at infy.route.MapOverlay.drawPath(MapRouteActivity.java:174)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at infy.route.MapOverlay.draw(MapRouteActivity.java:168)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at com.google.android.maps.OverlayBundle.draw(OverlayBundle.java:42)
02-23 23:20:20.960: ERROR/And开发者_如何学运维roidRuntime(804):     at com.google.android.maps.MapView.onDraw(MapView.java:476)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.View.draw(View.java:6274)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.drawChild(ViewGroup.java:1526)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1256)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.drawChild(ViewGroup.java:1524)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1256)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.View.draw(View.java:6277)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.widget.FrameLayout.draw(FrameLayout.java:352)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.drawChild(ViewGroup.java:1526)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1256)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.drawChild(ViewGroup.java:1524)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1256)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.View.draw(View.java:6277)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.widget.FrameLayout.draw(FrameLayout.java:352)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1883)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewRoot.draw(ViewRoot.java:1332)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewRoot.performTraversals(ViewRoot.java:1097)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1613)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.os.Looper.loop(Looper.java:123)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at android.app.ActivityThread.main(ActivityThread.java:4203)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at java.lang.reflect.Method.invokeNative(Native Method)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at java.lang.reflect.Method.invoke(Method.java:521)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
02-23 23:20:20.960: ERROR/AndroidRuntime(804):     at dalvik.system.NativeStart.main(Native Method)

(edit: reformatted code)

---

Overlay does not have resource. Pass reference to a Context (i.e. the Activity), and call getResources() on that instead.

Related question: Android getResource() undefined error

EDIT:

Change

MapOverlay mapOverlay = new MapOverlay(mRoad, mapView);

to

MapOverlay mapOverlay = new MapOverlay(MapRouteActivity.this, mRoad, mapView);

and:

public MapOverlay(Road road, MapView mv) {

to

Context context;
public MapOverlay(Context context, Road road, MapView mv) {
    this.context = context;

and finally, change the call to context.getResources().getDrawable(...