Rysowanie linii/ścieżki na Google Maps

Dla tych, którzytak naprawdę tylko chcą narysować prostą linię - istnieje również wersja skrócona.

GoogleMap map;
// ... get a map.
// Add a thin red line from London to New York.
Polyline line = map.addPolyline(new PolylineOptions()
    .add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
    .width(5)
    .color(Color.RED));

Od https://developers.google.com/maps/documentation/android/reference/com/google/android/gms/maps/model/Polyline

// This Activity will draw a line between two selected points on Map

public class MainActivity extends MapActivity {
 MapView myMapView = null;
 MapController myMC = null;
 GeoPoint geoPoint = null;

 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {


  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  myMapView = (MapView) findViewById(R.id.mapview);
  geoPoint = null;
  myMapView.setSatellite(false);

  String pairs[] = getDirectionData("ahmedabad", "vadodara");
  String[] lngLat = pairs[0].split(",");

  // STARTING POINT
  GeoPoint startGP = new GeoPoint(
    (int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double
      .parseDouble(lngLat[0]) * 1E6));

  myMC = myMapView.getController();
  geoPoint = startGP;
  myMC.setCenter(geoPoint);
  myMC.setZoom(15);
  myMapView.getOverlays().add(new DirectionPathOverlay(startGP, startGP));

  // NAVIGATE THE PATH

  GeoPoint gp1;
  GeoPoint gp2 = startGP;

  for (int i = 1; i < pairs.length; i++) {
   lngLat = pairs[i].split(",");
   gp1 = gp2;
   // watch out! For GeoPoint, first:latitude, second:longitude

   gp2 = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6),
     (int) (Double.parseDouble(lngLat[0]) * 1E6));
   myMapView.getOverlays().add(new DirectionPathOverlay(gp1, gp2));
   Log.d("xxx", "pair:" + pairs[i]);
  }

  // END POINT
  myMapView.getOverlays().add(new DirectionPathOverlay(gp2, gp2));

  myMapView.getController().animateTo(startGP);
  myMapView.setBuiltInZoomControls(true);
  myMapView.displayZoomControls(true);

 }

 @Override
 protected boolean isRouteDisplayed() {
  // TODO Auto-generated method stub
  return false;
 }

 private String[] getDirectionData(String srcPlace, String destPlace) {

  String urlString = "http://maps.google.com/maps?f=d&hl=en&saddr="
   + srcPlace + "&daddr=" + destPlace
   + "&ie=UTF8&0&om=0&output=kml";

  Log.d("URL", urlString);
  Document doc = null;
  HttpURLConnection urlConnection = null;
  URL url = null;
  String pathConent = "";

  try {

   url = new URL(urlString.toString());
   urlConnection = (HttpURLConnection) url.openConnection();
   urlConnection.setRequestMethod("GET");
   urlConnection.setDoOutput(true);
   urlConnection.setDoInput(true);
   urlConnection.connect();
   DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
   DocumentBuilder db = dbf.newDocumentBuilder();
   doc = db.parse(urlConnection.getInputStream());

  } catch (Exception e) {
  }

  NodeList nl = doc.getElementsByTagName("LineString");
  for (int s = 0; s < nl.getLength(); s++) {
   Node rootNode = nl.item(s);
   NodeList configItems = rootNode.getChildNodes();
   for (int x = 0; x < configItems.getLength(); x++) {
    Node lineStringNode = configItems.item(x);
    NodeList path = lineStringNode.getChildNodes();
    pathConent = path.item(0).getNodeValue();
   }
  }
  String[] tempContent = pathConent.split(" ");
  return tempContent;
 }

}


//*****************************************************************************

DirectionPathOverlay

public class DirectionPathOverlay extends Overlay {

    private GeoPoint gp1;
    private GeoPoint gp2;

    public DirectionPathOverlay(GeoPoint gp1, GeoPoint gp2) {
        this.gp1 = gp1;
        this.gp2 = gp2;
    }

    @Override
    public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
            long when) {
        // TODO Auto-generated method stub
        Projection projection = mapView.getProjection();
        if (shadow == false) {

            Paint paint = new Paint();
            paint.setAntiAlias(true);
            Point point = new Point();
            projection.toPixels(gp1, point);
            paint.setColor(Color.BLUE);
            Point point2 = new Point();
            projection.toPixels(gp2, point2);
            paint.setStrokeWidth(2);
            canvas.drawLine((float) point.x, (float) point.y, (float) point2.x,
                    (float) point2.y, paint);
        }
        return super.draw(canvas, mapView, shadow, when);
    }

    @Override
    public void draw(Canvas canvas, MapView mapView, boolean shadow) {
        // TODO Auto-generated method stub

        super.draw(canvas, mapView, shadow);
    }

}

Jest to Pełny kod źródłowy do rysowania ścieżki kierunku od szerokości i długości geograficznej źródłowej do szerokości i długości geograficznej docelowej. Zmieniłem powyższy kod, aby pasował do szerokości i długości geograficznej, a nie Źródła i miejsca przeznaczenia. Więc każdy, kto ma dostęp do jego szerokości i długości geograficznej przez gps, może uzyskać kierunek od jego urządzenia gps do współrzędnych celu.

Dzięki powyższym odpowiedziom mogliśmy dokonać takiej zmiany i uzyskać kierunek ścieżki.

public class DrawMapActivity extends MapActivity {
     MapView myMapView = null;
     MapController myMC = null;
     GeoPoint geoPoint = null;
     @Override
     public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);

      setContentView(R.layout.main);
      myMapView = (MapView) findViewById(R.id.mapview);

      geoPoint = null;
      myMapView.setSatellite(false);
      double fromLat = 12.303534;
      double fromLong = 76.64611;
      double toLat = 12.9715987;
      double toLong = 77.5945627;

      String sourceLat = Double.toString(fromLat);
      String sourceLong = Double.toString(fromLong);
      String destinationLat = Double.toString(toLat);
      String destinationLong = Double.toString(toLong);

      String pairs[] = getDirectionData(sourceLat,sourceLong, destinationLat, destinationLong );
      String[] lngLat = pairs[0].split(",");

      // STARTING POINT
      GeoPoint startGP = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double.parseDouble(lngLat[0]) * 1E6));

      myMC = myMapView.getController();
      geoPoint = startGP;
      myMC.setCenter(geoPoint);
      myMC.setZoom(10);
      myMapView.getOverlays().add(new DirectionPathOverlay(startGP, startGP));

      // NAVIGATE THE PATH

      GeoPoint gp1;
      GeoPoint gp2 = startGP;

      for (int i = 1; i < pairs.length; i++) {
       lngLat = pairs[i].split(",");
       gp1 = gp2;
       // watch out! For GeoPoint, first:latitude, second:longitude

       gp2 = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6),(int) (Double.parseDouble(lngLat[0]) * 1E6));
       myMapView.getOverlays().add(new DirectionPathOverlay(gp1, gp2));
       Log.d("xxx", "pair:" + pairs[i]);
      }

      // END POINT
      myMapView.getOverlays().add(new DirectionPathOverlay(gp2, gp2));

      myMapView.getController().animateTo(startGP);
      myMapView.setBuiltInZoomControls(true);
      myMapView.displayZoomControls(true);

     }

     @Override
     protected boolean isRouteDisplayed() {
      // TODO Auto-generated method stub
      return false;
     }

     private String[] getDirectionData(String sourceLat, String sourceLong, String destinationLat, String destinationLong) {


      String urlString = "http://maps.google.com/maps?f=d&hl=en&" +"saddr="+sourceLat+","+sourceLong+"&daddr="+destinationLat+","+destinationLong + "&ie=UTF8&0&om=0&output=kml";
      Log.d("URL", urlString);
      Document doc = null;
      HttpURLConnection urlConnection = null;
      URL url = null;
      String pathConent = "";

      try {

       url = new URL(urlString.toString());
       urlConnection = (HttpURLConnection) url.openConnection();
       urlConnection.setRequestMethod("GET");
       urlConnection.setDoOutput(true);
       urlConnection.setDoInput(true);
       urlConnection.connect();
       DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
       DocumentBuilder db = dbf.newDocumentBuilder();
       doc = db.parse(urlConnection.getInputStream());

      } catch (Exception e) {
      }

      NodeList nl = doc.getElementsByTagName("LineString");
      for (int s = 0; s < nl.getLength(); s++) {
       Node rootNode = nl.item(s);
       NodeList configItems = rootNode.getChildNodes();
       for (int x = 0; x < configItems.getLength(); x++) {
        Node lineStringNode = configItems.item(x);
        NodeList path = lineStringNode.getChildNodes();
        pathConent = path.item(0).getNodeValue();
       }
      }
      String[] tempContent = pathConent.split(" ");
      return tempContent;
     }

    }


    //*****************************************************************************



     class DirectionPathOverlay extends Overlay {

        private GeoPoint gp1;
        private GeoPoint gp2;

        public DirectionPathOverlay(GeoPoint gp1, GeoPoint gp2) {
            this.gp1 = gp1;
            this.gp2 = gp2;
        }

        @Override
        public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
                long when) {
            // TODO Auto-generated method stub
            Projection projection = mapView.getProjection();
            if (shadow == false) {

                Paint paint = new Paint();
                paint.setAntiAlias(true);
                Point point = new Point();
                projection.toPixels(gp1, point);
                paint.setColor(Color.BLUE);
                Point point2 = new Point();
                projection.toPixels(gp2, point2);
                paint.setStrokeWidth(2);
                canvas.drawLine((float) point.x, (float) point.y, (float) point2.x,(float) point2.y, paint);
            }
            return super.draw(canvas, mapView, shadow, when);
        }

        @Override
        public void draw(Canvas canvas, MapView mapView, boolean shadow) {
            // TODO Auto-generated method stub

            super.draw(canvas, mapView, shadow);
        }

    }

Hope it helps for inni użytkownicy Stack Overflow

Można to zrobić również za pomocą intentów:

  final Intent intent = new Intent(Intent.ACTION_VIEW,
    Uri.parse(
            "http://maps.google.com/maps?" +
            "saddr="+YOUR_START_LONGITUDE+","+YOUR_START_LATITUDE+"&daddr="YOUR_END_LONGITUDE+","+YOUR_END_LATITUDE));
         intent.setClassName(
          "com.google.android.apps.maps",
          "com.google.android.maps.MapsActivity");
   startActivity(intent);

Tak, musisz używać nakładek.

Musisz pobrać nakładki MapView i dodać do niej nową nakładkę.

Twoja klasa rozszerza nakładkę, która jest przezroczystym płótnem, na którym możesz rysować jak każde inne płótno.

Możesz użyć mapView.getProjection() do wyświetlenia widoku mapy.

...

Więcej informacji można znaleźć tutaj: http://blogoscoped.com/archive/2008-12-15-n14.html

To naprawdę proste z Google Maps Android API v2

Wystarczy skopiować przykład z dokumentacji programisty

(oczywiście najpierw musisz init swojej mapy)

GoogleMap map;
 // ... get a map.
 // Add a thin red line from London to New York.
 Polyline line = map.addPolyline(new PolylineOptions()
     .add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
     .width(5)
     .color(Color.RED));

Rzut można uzyskać z obiektu MapView, który jest przekazywany do metody draw() : mapv.getProjection ().toPixels (gP1, p1);

public class MainActivity extends FragmentActivity  {


  List<Overlay> mapOverlays;
  GeoPoint point1, point2;
  LocationManager locManager;
  Drawable drawable;
  Document document;
  GMapV2GetRouteDirection v2GetRouteDirection;
  LatLng fromPosition;
  LatLng toPosition;
  GoogleMap mGoogleMap;
  MarkerOptions markerOptions;
  Location location ;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        v2GetRouteDirection = new GMapV2GetRouteDirection();
      SupportMapFragment supportMapFragment = (SupportMapFragment) getSupportFragmentManager()
        .findFragmentById(R.id.map);
        mGoogleMap = supportMapFragment.getMap();

        // Enabling MyLocation in Google Map
        mGoogleMap.setMyLocationEnabled(true);
        mGoogleMap.getUiSettings().setZoomControlsEnabled(true);
        mGoogleMap.getUiSettings().setCompassEnabled(true);
        mGoogleMap.getUiSettings().setMyLocationButtonEnabled(true);
        mGoogleMap.getUiSettings().setAllGesturesEnabled(true);
        mGoogleMap.setTrafficEnabled(true);
        mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(12));
        markerOptions = new MarkerOptions();
        fromPosition = new LatLng(11.663837, 78.147297);
        toPosition = new LatLng(11.723512, 78.466287);
        GetRouteTask getRoute = new GetRouteTask();
        getRoute.execute();
  }
  /**
   *
   * @author VIJAYAKUMAR M
   * This class Get Route on the map
   *
   */
  private class GetRouteTask extends AsyncTask<String, Void, String> {

        private ProgressDialog Dialog;
        String response = "";
        @Override
        protected void onPreExecute() {
              Dialog = new ProgressDialog(MainActivity.this);
              Dialog.setMessage("Loading route...");
              Dialog.show();
        }

        @Override
        protected String doInBackground(String... urls) {
              //Get All Route values
                         document = v2GetRouteDirection.getDocument(fromPosition, toPosition,          GMapV2GetRouteDirection.MODE_DRIVING);
                    response = "Success";
              return response;

        }

        @Override
        protected void onPostExecute(String result) {
              mGoogleMap.clear();
              if(response.equalsIgnoreCase("Success")){
              ArrayList<LatLng> directionPoint = v2GetRouteDirection.getDirection(document);
              PolylineOptions rectLine = new PolylineOptions().width(10).color(
                          Color.RED);

              for (int i = 0; i < directionPoint.size(); i++) {
                    rectLine.add(directionPoint.get(i));
              }
              // Adding route on the map
              mGoogleMap.addPolyline(rectLine);
              markerOptions.position(toPosition);
              markerOptions.draggable(true);
              mGoogleMap.addMarker(markerOptions);

              }

              Dialog.dismiss();
        }
  }
  @Override
  protected void onStop() {
        super.onStop();
        finish();
    }
 }

Klasa Pomocnicza trasy

 public class GMapV2GetRouteDirection {
  public final static String MODE_DRIVING = "driving";
  public final static String MODE_WALKING = "walking";

  public GMapV2GetRouteDirection() { }

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

Po prostu znajdę rysunek z jakimś prostokątem w mapview po prostu chcemy zmienić farbę jak chcemy

EmptyOverlay.java

public class EmptyOverlay extends Overlay {
private float x1,y1;
private MapExampleActivity mv = null;
private Overlay overlay = null;

public EmptyOverlay(MapExampleActivity mapV){
    mv = mapV;
}

@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
        long when) {
    // TODO Auto-generated method stub
    return super.draw(canvas, mapView, shadow, when);
}

@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
    if(mv.isEditMode()){
        if(e.getAction() == MotionEvent.ACTION_DOWN){
            //when user presses the map add a new overlay to the map
            //move events will be catched by newly created overlay
            x1 = y1 = 0;
            x1 = e.getX();
            y1 = e.getY();

            overlay = new MapOverlay(mv, x1, y1);
            mapView.getOverlays().add(overlay);

        }
        if(e.getAction() == MotionEvent.ACTION_MOVE){
        }
        //---when user lifts his finger---
        if (e.getAction() == MotionEvent.ACTION_UP) {                

        }    
        return true;
    }
    return false;
}
}

 public class MapExampleActivity extends MapActivity {
private MapView mapView;
private boolean isEditMode = false;
private Button toogle;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    toogle = (Button)findViewById(R.id.toogleMap);        
    toogle.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            toogleEditMode();

        }
    });

    mapView = (MapView)findViewById(R.id.mapview);
    mapView.setBuiltInZoomControls(true); //display zoom controls
    //add one empty overlay acting as a overlay loader. This will catch press events and will add the actual overlays
    mapView.getOverlays().add(new EmptyOverlay(this));
    mapView.postInvalidate();
}
//toogle edit mode for drawing or navigating the map
private void toogleEditMode(){
    isEditMode = !isEditMode;
}

@Override
protected boolean isRouteDisplayed() {
    // TODO Auto-generated method stub
    return false;
}
@Override
protected boolean isLocationDisplayed() {
    return false;
}

public boolean isEditMode(){
    return this.isEditMode;
}

public MapView getMapView(){
    return this.mapView;
}
}

MapOverlay.java

 public class MapOverlay extends Overlay {

private float x1,y1,x2,y2;
private GeoPoint p1=null,p2=null;
private MapExampleActivity mv = null;
private Paint paint = new Paint();
private boolean isUp = false;

//constructor receiving the initial point
public MapOverlay(MapExampleActivity mapV,float x,float y){
    paint.setStrokeWidth(2.0f);
    x1 = x;
    y1 = y;
    mv = mapV;
    p1 = mapV.getMapView().getProjection().fromPixels((int)x1,(int)y1);
}
//override draw method to add our custom drawings
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
        long when) {

    if(p1 != null && p2 != null){
        //get the 2 geopoints defining the area and transform them to pixels
        //this way if we move or zoom the map rectangle will follow accordingly
        Point screenPts1 = new Point();
        mapView.getProjection().toPixels(p1, screenPts1);
        Point screenPts2 = new Point();
        mapView.getProjection().toPixels(p2, screenPts2);

        //draw inner rectangle
        paint.setColor(0x4435EF56);
        paint.setStyle(Style.FILL);
        canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
        //draw outline rectangle
        paint.setColor(0x88158923);
        paint.setStyle(Style.STROKE);
        canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
    }
    return true;
}

@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
    if(mv.isEditMode() && !isUp){
        if(e.getAction() == MotionEvent.ACTION_DOWN){
            x1 = y1 = 0;
            x1 = e.getX();
            y1 = e.getY();
            p1 = mapView.getProjection().fromPixels((int)x1,(int)y1);

        }
        //here we constantly change geopoint p2 as we move out finger
        if(e.getAction() == MotionEvent.ACTION_MOVE){
            x2 = e.getX();
            y2 = e.getY();
            p2 = mapView.getProjection().fromPixels((int)x2,(int)y2);

        }
        //---when user lifts his finger---
        if (e.getAction() == MotionEvent.ACTION_UP) {                
            isUp = true;
        }    
        return true;
    }
    return false;
}
 }

Zobacz to http://n3vrax.wordpress.com/2011/08/13/drawing-overlays-on-android-map-view/

Try this one:
Add itemizedOverlay class:

public class AndroidGoogleMapsActivity extends MapActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Displaying Zooming controls
        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);


        MapController mc = mapView.getController();
        double lat = Double.parseDouble("48.85827758964043");
        double lon = Double.parseDouble("2.294543981552124");
        GeoPoint geoPoint = new GeoPoint((int)(lat * 1E6), (int)(lon * 1E6));
        mc.animateTo(geoPoint);
        mc.setZoom(15);
        mapView.invalidate(); 


        /**
         * Placing Marker
         * */
        List<Overlay> mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.mark_red);
        AddItemizedOverlay itemizedOverlay = 
             new AddItemizedOverlay(drawable, this);


        OverlayItem overlayitem = new OverlayItem(geoPoint, "Hello", "Sample Overlay item");

        itemizedOverlay.addOverlay(overlayitem);
        mapOverlays.add(itemizedOverlay);

    }

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

To mi pomogło. Dzięki wspomnianej tu metodzie udało mi się narysować polilinię na Google Maps V2. Narysowałem nową linię za każdym razem, gdy lokalizacja użytkownika została zmieniona, więc polilinia wygląda jak ścieżka, po której następuje użytkownik na mapie.

Kod źródłowy w. Github: prasang7 / eTaxi-Meter

Proszę zignorować inne moduły tego projektu związane z obliczaniem odległości i interfejsem użytkownika, jeśli nie są one zainteresowane.