want to draw a line between any two location in android

问题

This is my main activity

import java.net.HttpURLConnection;
import java.net.URL;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import android.os.Bundle;
import android.util.Log;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;

public class DrawActivity extends MapActivity {
 MapView myMapView = null;
 MapController myMC = null;
 GeoPoint geoPoint = null;
  String pairs[]=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);
  System.out.println("before pairs");
  String pairs[] = getDirectionData("Hyderabad","hyderguda");

  System.out.println("pairs:"+pairs[1]);
  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());

 //The above code "doc" is getting null value so thats why its getting crashed here itself not going further execution and returning as `nullpointerexception`
  } 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;
 }

}

and my another part of code package com.hands;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.Projection;

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);
}

}

The above is my complete source code plz help me out from this problem

回答1:

You are using output=kml, this parameter no longer works. You get the error because this URL now retrieves a webpage not KML file.

This way of extracting the Google Directions from Google by parsing the KML file is no longer available since 27 July 2012 (because Google has changed the structure of retrieving Google Directions, now you can only get it by JSON or XML), it is time to migrate your code to JSON instead of KML.

See the answer in my own question here.

来源：https://stackoverflow.com/questions/11932797/want-to-draw-a-line-between-any-two-location-in-android