public Uri writeToFolder(final Folder folder, final String filename) {

        final Charset encoding = StandardCharsets.UTF_16LE;

        final String content = getContent();

        final Uri uri = ContentStorage.get().create(folder, filename);
        if (uri == null) {
            return null;
        }

        Writer writer = null;
        try {
            final OutputStream os = ContentStorage.get().openForWrite(uri);
            if (os == null) {
                return null;
            }

            writer = new OutputStreamWriter(os, encoding);
            IOUtils.write(content, writer);
            writer.flush();
        } catch (final IOException e) {
            Log.e("writing field notes failed", e);
            // delete partial file on error
            ContentStorage.get().delete(uri);

            return null;
        } finally {
            IOUtils.closeQuietly(writer);
        }

        return uri;
    }
Field Notes are simple plain text files, but poorly documented. Syntax:<br>

<pre>
GCxxxxx,yyyy-mm-ddThh:mm:ssZ,Found it,"logtext"
</pre>
main/src/main/java/cgeo/geocaching/export/FieldNotes.java