Android Open Source - ElevationLogger Gpx Writer

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License

The source code is released under:

GNU General Public License

Java Source Code

package de.smashnet.elevationlogger;
/*from  www  . jav  a2  s. c o m*/
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Serializable;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.util.Log;

/**
 * This class should simplify the creation of GPX files.
 * 
 * @author Nicolas Inden
 * @contact nicolas.inden@smashnet.de
 * @date 29.12.2013
 */
public class GpxWriter implements Serializable{
  /**
   * 
   */
  private static final long serialVersionUID = -3172959510015296715L;

  /**
   * Name of the gpx file
   */
  private String mFilename;
  
  /**
   * Directory where the file should be stored
   */
  private File mDirectory;
  
  /**
   * Creation date of this file
   */
  private Date mTime;
  
  /**
   * Helps buffering contents before they are written to file
   */
  private StringBuilder mSB;
  
  /**
   * If a file is finished, all following route points are ignored
   * A file is finished if the footer is written. 
   */
  private boolean mFinished = false;
  
  /**
   * Basic constructor
   * 
   * @param file is used as filename but gets the date prepended at the beginning
   * @param dir the directory where the file should be saved
   */
  public GpxWriter(Date time, File dir, String file) {
    mTime = time;
    
    // Create readable date string
    SimpleDateFormat sDateFormat = new SimpleDateFormat("yyMMdd-HHmm", Locale.GERMANY);
    String date = sDateFormat.format(mTime);
    
    mFilename = date + "_" + file;
    mDirectory = dir;
    mSB = new StringBuilder();
  }
  
  /**
   * Writes a standard GPX file header in the StringBuilder buffer
   */
  public void writeHeader() {
    Log.i("GpxWriter", "Logging to file: " + mFilename);
    SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.GERMANY);
    String date = sDateFormat.format(mTime);
    mSB.append("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?>\n");
    mSB.append("<gpx version=\"1.1\" creator=\"ElevationLogger v0.1 experimental\">\n");
    mSB.append("\t<metadata>\n");
    mSB.append("\t\t<name>" + mFilename + "</name>\n");
    mSB.append("\t\t<time>" + date + "</time>\n");
    mSB.append("\t\t<author>\n");
    mSB.append("\t\t\t<name>ElevationLogger</name>\n");
    mSB.append("\t\t</author>\n");
    mSB.append("\t</metadata>\n");
    mSB.append("\t<trk>\n");
    mSB.append("\t\t<name>ElevationLogger recording</name>\n");
    mSB.append("\t\t<desc></desc>\n");
    mSB.append("\t\t<trkseg>\n");
  }
  
  /**
   * Writes a standard GPX file footer in the StringBuilder buffer and declares
   * this file as finished
   */
  public void writeFooter() {
    mSB.append("\t\t</trkseg>\n");
    mSB.append("\t</trk>\n");
    mSB.append("</gpx>\n");
    mFinished = true;
  }
  
  /**
   * Add a route point to the StringBuidler buffer with the following values:
   * 
   * @param lat the latitude value
   * @param lon the longitude value
   * @param alt the altitude value
   * @param acc the accuracy of lat/lon
   * @param mbar the air pressure
   * @param time the UTC time of the corresponding GPS fix
   */
  public void addRoutePoint(double lat, double lon, double alt, float acc, double mbar, long time, long osm) {
    if(mFinished)
      return;
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.GERMANY);
    String isoTime = df.format(new Date(time));
    mSB.append("\t\t\t<trkpt lat=\"" + lat + "\" lon=\"" + lon + "\">\n");
    mSB.append("\t\t\t\t<ele>" + alt + "</ele>\n");
    mSB.append("\t\t\t\t<time>" + isoTime + "</time>\n");
    mSB.append("\t\t\t\t<extensions>\n");
    mSB.append("\t\t\t\t\t<accuracy>" + acc + "</accuracy>\n");
    mSB.append("\t\t\t\t\t<airpressure>" + mbar + "</airpressure>\n");
    mSB.append("\t\t\t\t\t<nearestosm>" + osm + "</nearestosm>\n");
    mSB.append("\t\t\t\t</extensions>\n");
    mSB.append("\t\t\t</trkpt>\n");
  }
  
  /**
   * Takes all contents of the StringBuilder buffer
   * and writes it to the storage device, finally clearing
   * the StringBuilder buffer
   */
  public void flushToFile() {
    try {
      File measurefile = new File(mDirectory, mFilename);
      if(!measurefile.exists())
        if(!measurefile.createNewFile())
          System.out.println("Couldn't create file");
      
      FileWriter measurefile_writer = new FileWriter(measurefile, true);
      measurefile_writer.append(mSB.toString());
      measurefile_writer.close();
      
      // Clear stringbuilder
      mSB = new StringBuilder();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  public String getFilename() {
    return mFilename;
  }

  public void setFilename(String filename) {
    this.mFilename = filename;
  }

  public File getDirectory() {
    return mDirectory;
  }

  public void setDirectory(File directory) {
    this.mDirectory = directory;
  }
}

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