GetMapDirection.java

package com.ese2013.mensaunibe.map;

import java.io.InputStream;
import java.util.ArrayList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import android.util.Log;

import com.google.android.gms.maps.model.LatLng;

/**
 * @author group7
 * @author Marc Dojtschinov
 */

public class GetMapDirection {

	/**
	 * Connects with google mpa api and request direction 
	 * @param start Starting point for directions request
	 * @param end Endpoint for directions request
	 * @param mode travel mode e.g. walking 
	 */
	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="+ mode;

	    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();
	}
	
	/**
	 * 
	 * @param doc Googlemap direction request Document
	 * @return Array<LatLng> with Geopoints of the route
	 */
	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;
	}
	/**
	 * 
	 * @param encoded takes a encoded coordniates String
	 * @return Array<LatLng> with Geopoints
	 */

	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;
	}

}