How to Draw Route in Google Maps API V2 from my lo

问题:

This question already has an answer here:

• Android: How to draw route directions google maps API V2 from current location to destination 4 answers

I want to make direction application but, i have problem to draw route from my location to destination, i get variabel longitude and latitude from my location , but i dont know to draw line .. i want to draw direction to this location = -6.984873352070259,108.48140716552734. please help me guys.. i have read the quetions before but i cant get solution.. thanks.. iam sorry before.. here is my code

package com.apps.visitkuningan;

import android.app.Dialog;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.widget.Toast;


import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;

public class Arahkan extends FragmentActivity implements LocationListener {

    GoogleMap googleMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Getting Google Play availability status
        int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

        // Showing status
        if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

            int requestCode = 10;
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
            dialog.show();

        }else { // Google Play Services are available

            // Getting reference to the SupportMapFragment of activity_main.xml
            SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

            // Getting GoogleMap object from the fragment
            googleMap = fm.getMap();

            // Enabling MyLocation Layer of Google Map
            googleMap.setMyLocationEnabled(true);

            // Getting LocationManager object from System Service LOCATION_SERVICE
            LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

            // Creating a criteria object to retrieve provider
            Criteria criteria = new Criteria();

            // Getting the name of the best provider
            String provider = locationManager.getBestProvider(criteria, true);

            // Getting Current Location
            Location location = locationManager.getLastKnownLocation(provider);

            if(location!=null){
                onLocationChanged(location);
            }
            locationManager.requestLocationUpdates(provider, 20000, 0, this);
        }
    }
    @Override
    public void onLocationChanged(Location location) {

        // Getting latitude of the current location
        double latitude = location.getLatitude();

        // Getting longitude of the current location
        double longitude = location.getLongitude();

        // Creating a LatLng object for the current location
        LatLng latLng = new LatLng(latitude, longitude);

        // Showing the current location in Google Map
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

        // Zoom in the Google Map
        googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));

    }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub
         Toast.makeText( getApplicationContext(), "Gps Disabled", Toast.LENGTH_SHORT ).show();
    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
         Toast.makeText( getApplicationContext(), "Gps Enabled", Toast.LENGTH_SHORT).show();

    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub
    }

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


}

Iam newbie in android programming i hope you can help me.. thanks.. :)

回答1:

Assuming you have at least 2 location objects you can draw a polyline. This method draws a semi-transparent blue line on the map given a list of locations. This code is taken from an application currently on the Android Play store (Simply Walking).

private void drawPrimaryLinePath( ArrayList<Location> listLocsToDraw )
{
    if ( map == null )
    {
        return;
    }

    if ( listLocsToDraw.size() < 2 )
    {
        return;
    }

    PolylineOptions options = new PolylineOptions();

    options.color( Color.parseColor( "#CC0000FF" ) );
    options.width( 5 );
    options.visible( true );

    for ( Location locRecorded : listLocsToDraw )
    {
        options.add( new LatLng( locRecorded.getLatitude(),
                                 locRecorded.getLongitude() ) );
    }

    map.addPolyline( options );

}

回答2:

Firstly you can get the directions between two location co-ordinates using the Google Directions API.

public static ArrayList getDirections(double lat1, double lon1, double lat2, double lon2) {
    String url = "http://maps.googleapis.com/maps/api/directions/xml?origin=" +lat1 + "," + lon1  + "&destination=" + lat2 + "," + lon2 + "&sensor=false&units=metric";
    String tag[] = { "lat", "lng" };
    ArrayList list_of_geopoints = new ArrayList();
    HttpResponse response = null;
    try {
        HttpClient httpClient = new DefaultHttpClient();
        HttpContext localContext = new BasicHttpContext();
        HttpPost httpPost = new HttpPost(url);
        response = httpClient.execute(httpPost, localContext);
        InputStream in = response.getEntity().getContent();
        DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
        Document doc = builder.parse(in);
        if (doc != null) {
            NodeList nl1, nl2;
            nl1 = doc.getElementsByTagName(tag[0]);
            nl2 = doc.getElementsByTagName(tag[1]);
            if (nl1.getLength() > 0) {
                list_of_geopoints = new ArrayList();
                for (int i = 0; i < nl1.getLength(); i++) {
                    Node node1 = nl1.item(i);
                    Node node2 = nl2.item(i);
                    double lat = Double.parseDouble(node1.getTextContent());
                    double lng = Double.parseDouble(node2.getTextContent());
                    list_of_geopoints.add(new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6)));
                }
            } else {
                // No points found
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return list_of_geopoints;
}

Once a MapView layout is created in your android app, you can include this customized Overlay class.

public class MyOverlay extends Overlay {

private ArrayList all_geo_points;

public MyOverlay(ArrayList allGeoPoints) {
    super();
    this.all_geo_points = allGeoPoints;
}

@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) {
    int xPrev = -1, yPrev = -1, xNow = -1, yNow = -1;
    Paint paint = new Paint();
    paint.setColor(Color.BLUE);
    paint.setStyle(Paint.Style.FILL_AND_STROKE);
    paint.setStrokeWidth(4);
paint.setAlpha(100);
    if (all_geo_points != null)
        for (int i = 0; i < all_geo_points.size() - 4; i++) {
            GeoPoint gp = all_geo_points.get(i);
            Point point = new Point();
            mv.getProjection().toPixels(gp, point);
            xNow = point.x;
            yNow = point.y;
            if (xPrev != -1) {
                canvas.drawLine(xPrev, yPrev, xNow, yNow, paint);
            }
            xPrev = xNow;
            yPrev = yNow;
        }
    }
}

The getDirections() function can be called right before before adding this Overlay to the MapView’s overlays.

MapView mv = (MapView) findViewById(R.id.mvGoogle);
mv.setBuiltInZoomControls(true);
MapController mc = mv.getController();
ArrayList all_geo_points = getDirections(17.3849, 78.4866, 28.63491, 77.22461);
GeoPoint moveTo = all_geo_points.get(0);
mc.animateTo(moveTo);
mc.setZoom(12);
mv.getOverlays().add(new MyOverlay(all_geo_points));

回答3:

You can use Drawing on Map feature dude:

• https://developers.google.com/maps/documentation/android/shapes