Android Open Source - CrimeSweeper Crime Site

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From Project

Back to project page CrimeSweeper.

License

The source code is released under:

Apache License

Java Source Code

package com.markupartist.crimesweeper;
import com.google.android.maps.GeoPoint;
import java.lang.Math;
import java.util.List;
import java.util.ArrayList;
/*www  . j a  va  2 s  . c  o  m*/
import java.io.IOException;

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

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import java.net.*;
import android.location.Location;

public class CrimeSite extends GeoPoint {
  float collisionDistance = 100.0f;
  private static final String TAG = "Collision: ";
    private String mTitle;
      
  String getTitle()
  {
    return mTitle;
  }

  boolean intersectWithPlayer(Location player)
  {
        Location crimeSiteLocation = new Location(player);
        crimeSiteLocation.setLatitude(this.getLatitudeE6() / 1000000.0);
        crimeSiteLocation.setLongitude(this.getLongitudeE6() / 1000000.0);

        float distance = player.distanceTo(crimeSiteLocation);
        return(distance <= this.collisionDistance);
  }
  
  static List<CrimeSite> getCrimeSites(int minutes)
  {
    List<CrimeSite> crimeSites = new ArrayList<CrimeSite>();
    
    try {
      Document xmlDoc = loadDocument("http://brottsplatsstockholm.se/api.php?action=getEvents&period=" + minutes);
      NodeList nodes = getEventNodes(xmlDoc);
      
      // NOTE: We skip every other element because it's a "text" element.
      // TODO: Look into why this is so, and if we're misusing this API somehow :)
      for(int i = 1; i < nodes.getLength(); i+=2)                  
        crimeSites.add(new CrimeSite(getValueByElementName(nodes.item(i), "titleCleaned"),
                       getCordinate(nodes.item(i), "lat"),
                       getCordinate(nodes.item(i), "lng")));
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    
    return crimeSites;
  }

  CrimeSite(String title, int lat, int lng) {
        super(lat, lng);
    mTitle = title;
  }
  
private

  static NodeList getEventNodes(Document xmlDoc)
  {
    return xmlDoc.getChildNodes().item(0).getChildNodes();
  }

  static Document loadDocument(String url) throws MalformedURLException, SAXException, IOException, ParserConfigurationException, FactoryConfigurationError
  {
    DocumentBuilder docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
    return docBuilder.parse(new URL(url).openConnection().getInputStream());  
  }

  static int getCordinate(Node node, String name)
  {
    return (int)(Float.valueOf(getValueByElementName(node, name)).doubleValue() * 1000000);
  }

  static String getValueByElementName(Node eventNode, String elementName)
  {
    NodeList eventChildren = eventNode.getChildNodes();
    for(int i = 1; i < eventChildren.getLength(); i += 2)
    {
      Node node = eventChildren.item(i);
      if(node.getNodeName().equals(elementName))
        return getValueForNode(node);
    }
    
    return "";
  }
  
  static String getValueForNode(Node node)
  {
    // TODO: Why do we have to do this? Seems a bit odd.
    NodeList contentNodes = node.getChildNodes();
    Node cdata_node = contentNodes.item(contentNodes.getLength() - 1);
    return cdata_node.getNodeValue();    
  }

  /*
   * The great circle distance d between two points with coordinates {lat1,lon1} and {lat2,lon2} is given by:
   * d=acos(sin(lat1)*sin(lat2)+cos(lat1)*cos(lat2)*cos(lon1-lon2))
   */
  double distanceBetweenCoords(int lat1, int lon1, int lat2, int lon2) {
    return Math.acos( 
      Math.sin(lat1) * Math.sin(lat2) + Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2)
    );
  }    
}

Java Source Code List

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