[Simple-support] How to append elements to existing XML file

[Cody D D. <cdd...@st...>]

Hello,

I have been trying to figure this out for some time now and have decided its time to consult the mailing list.  My issue deals with the creation of a GPX file for GPS use in Android.  The basic structure that I am wanting for my XML file is shown below.  I have achieved the structure using Simple, but cannot figure out how to only add additional trkpt elements when I update the file.  Every time my android device receives a GPS location I need to just write another trkpt to the existing xml file, but my program is repeating the entire structure shown below with each new location.  I am assuming there is a way to append just a single element to an already existing XML file and have it maintain the tree structure (just like the two trkpts shown below).  I have also placed a copy of the code that is currently run every time my application receives a new location point below.  Thanks for any help you can offer!

Cody


File Structure
<?xml version="1.0" encoding="UTF-8"?>
<gpx xmlns="http://www.topografix.com/GPX/1/1"
    version="1.1"
    creator="Cody"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.topografix.com/GPX/1/1/gpx.xsd">
        <trk>
            <trkseg>
                <trkpt lon="9.860624216140083" lat="54.9328621088893">
                    <ele>228.0</ele>
                    <time>2011-12-20T22:46:16Z</time>
                    <speed>13.0</speed>
                    <src>gps</src>
                </trkpt>
                <trkpt lon="9.860624216140083" lat="54.9328621088893">
                    <ele>228.0</ele>
                    <time>2011-12-20T22:46:16Z</time>
                    <speed>13.0</speed>
                    <src>gps</src>
                </trkpt>
            </trkseg>
        </trk>
</gpx>

Current Writing Code

            String prolog = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
            Format format = new Format(prolog);
            Serializer serializer = new Persister(format);

            Gpx gpx = new Gpx();

            Trk trk = new Trk();
            gpx.setTrk(trk);

            Trkseg trkseg = new Trkseg();
            trk.setTrkseg(trkseg);

            Trkpt trkpt = new Trkpt();
            trkpt.setLon(String.valueOf(loc.getLongitude()));
            trkpt.setLat(String.valueOf(loc.getLatitude()));
            trkpt.setEle(String.valueOf(loc.getAltitude()));
            trkpt.setTime(dateTimeString);
            trkpt.setSpeed(String.valueOf(loc.getSpeed()));
            trkpt.setSrc(loc.getProvider());
            trkseg.setTrkpt(trkpt);

            FileWriter fstream = new FileWriter(gpxFile, true);
            BufferedWriter out = new BufferedWriter(fstream);

            serializer.write(gpx, out);