android如何在谷歌地图上用中间点绘制从起点到目的地的路线？

Question

I have start point,intermediate point and destination point. start point and destination point is same now i want to cover all points and reach to same destination point on Google map in Android so, how it will be possible. Thank you in Advanced....

Answer 1

To draw a route from A to B, I use the following code (unfortunately I cannot remember where I got it but credit does not go to me):

public class GMapV2Direction {

    private final static String TAG = "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)
            throws InterruptedException, ExecutionException, TimeoutException {
        final 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";

        Log.d(TAG, url);

        try {
            Log.d(TAG, "Fetching directions");
            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) {
            Log.e(TAG, e.getMessage(), e);
        }
        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;
    }
}

To use it I use this code (the calls to the googlemaps is a code module that I have implemented but if you parse you GoogleMap object, you should be able to draw the route, same goes for AddressHolder, which just supplies the destination position):

private void addDirectionsToMap(GoogleMap map, AddressHolder addressHolder,
        boolean zoomToBounds) {

    Log.i(TAG, "addDirectionsToMap");

    Location lastLocation = location.getLastLocation();

    if (lastLocation == null) {
        // TODO res/string
        Toast.makeText(context, "Unable to get device position",
                Toast.LENGTH_LONG).show();
        return;
    }

    map.setTrafficEnabled(getPreferences().showTraffic());
    map.setMapType(getPreferences().getMapType());

    googlemaps.addLocationPin(lastLocation);
    googlemaps.addAddressPin(addressHolder);

    new GetDirectionsTask(zoomToBounds).execute(
            new LatLng(lastLocation.getLatitude(), lastLocation
                    .getLongitude()), addressHolder.position);

}

private class GetDirectionsTask extends
        AsyncTask<LatLng, Integer, List<LatLng>> {

    private boolean zoomToBounds;

    public GetDirectionsTask(boolean zoomToBounds) {
        this.zoomToBounds = zoomToBounds;
    }

    // Before running code in separate thread
    @Override protected void onPreExecute() {
        // Create a new progress dialog.
        // progressDialog = new ProgressDialog(context);
        // progressDialog.setMessage("Henter rute...");
        // progressDialog.setCancelable(false);
        // progressDialog.setIndeterminate(true);
        // progressDialog.show();

    }

    // The code to be executed in a background thread.
    @Override protected List<LatLng> doInBackground(LatLng... position) {
        LatLng fromPosition = position[0];
        LatLng toPosition = position[1];

        GMapV2Direction md = new GMapV2Direction();

        List<LatLng> directionPoints = null;
        Document doc;
        try {
            doc = md.getDocument(fromPosition, toPosition,
                    GMapV2Direction.MODE_DRIVING);

            if (doc != null) {
                directionPoints = md.getDirection(doc);
            } else {
                Log.d(TAG, "Directions document was null");
            }
        } catch (InterruptedException e) {
            Log.e(TAG, e.getMessage(), e);
        } catch (ExecutionException e) {
            Log.e(TAG, e.getMessage(), e);
        } catch (TimeoutException e) {
            Log.e(TAG, e.getMessage(), e);
        }
        return directionPoints;
    }

    // Update the progress
    @Override protected void onProgressUpdate(Integer... values) {
        // set the current progress of the progress dialog
        // progressDialog.setProgress(values[0]);
    }

    // after executing the code in the thread
    @Override protected void onPostExecute(List<LatLng> directionPoint) {
        // close the progress dialog
        // progressDialog.dismiss();
        final GoogleMap map = googlemaps.getMap();

        if (directionPoint == null)
            return;
        if (map == null)
            return;

        PolylineOptions rectLine = new PolylineOptions().width(3).color(
                Color.RED);

        LatLngBounds.Builder builder = new LatLngBounds.Builder();

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

            builder.include(directionPoint.get(i));
        }

        map.addPolyline(rectLine);

        final LatLngBounds bounds = builder.build();

        final int padding = 50; // offset from edges of the
        // map in pixels

        if (zoomToBounds) {
            try {
                googlemaps.zoomWithBounds(bounds, padding);
            } catch (Exception e) {

                // if map is just created we have to wait for it to be ready

                map.setOnCameraChangeListener(new OnCameraChangeListener() {

                    @Override public void onCameraChange(CameraPosition arg0) {
                        // Move camera.

                        googlemaps.zoomWithBounds(bounds, padding);

                        // Remove listener to prevent position reset on
                        // camera move.
                        map.setOnCameraChangeListener(null);

                    }
                });
            }
        }

    }
}

Have not tried to use this code for multiple routes but cannot see any reason for this not to work by getting directions A -> B, B -> C and finally C -> A.

Answer 2

I don't know if it is possible, but you can draw a map in Google Maps, put on the points, and draw the line with the path you want. Export to kml file and use it in your app.