Itext show empty cells in table for Arabic words

Question

I am using Itext to create pdf files in android using this code:

public class CreatingPDF {

private List<SearchResult> mSearchResult;
private Context mContext;
private String mCost;
private String mPdfTitle;

private PdfWriter mPdfWriter;

private static Font catFont;
private static Font redFont;
private static Font subFont;
private static Font smallBold;

public CreatingPDF(Context context, List<SearchResult> searchResults, String title, String cost) throws IOException, DocumentException {

    catFont = FontFactory.getFont("assets/artro.ttf",BaseFont.IDENTITY_H,18,Font.ITALIC);
    redFont = new Font(Font.FontFamily.COURIER, 12, Font.NORMAL, BaseColor.RED);
    subFont = new Font(Font.FontFamily.TIMES_ROMAN, 16, Font.BOLD);
    smallBold = new Font(Font.FontFamily.TIMES_ROMAN, 12, Font.BOLD);

    mContext = context;
    mSearchResult = searchResults;
    mPdfTitle = title;
    mCost = cost;
    createPDF();
}

private void createPDF() {
    Date date = new Date();
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(date);
    String filename = mContext.getResources().getString(R.string.report_title) + timeStamp;

    File pdfFolder = new File(Environment.getExternalStorageDirectory() + "/" +
            mContext.getResources().getString(R.string.app_name));

    File myFile = new File( pdfFolder + "/" + filename + ".pdf");

    if (pdfFolder.exists()) {
        Log.e("File : ", "FileAlreadyHere");
    } else {
        Log.e("File : ", "FileNotHere");
        pdfFolder.mkdirs();
    }

    try {
        Document document = new Document();
        OutputStream output = new FileOutputStream(myFile);
        mPdfWriter = PdfWriter.getInstance(document, output);
        document.open();
        addMetaData(document);
        addTitlePage(document);
        document.close();
        Log.e("CreatingPdf ", "Pdf Created");

        Intent target = new Intent(Intent.ACTION_VIEW);
        target.setDataAndType(Uri.fromFile(myFile), "application/pdf");
        target.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);

        Intent intent = Intent.createChooser(target, "Open File");
        try {
            mContext.startActivity(intent);
            ((Activity) mContext).finish();
        } catch (ActivityNotFoundException e) {
            Log.e("ActivityEx ",e.getMessage());
        }

    } catch (Exception e) {
        Log.e("CreatingPdf Exception ", e.getMessage() + "");
    }

}


private void addMetaData(Document document) {
    document.addTitle("Report");
    document.addAuthor("Ahmed Moharm");
    document.addCreator("Ahmed Moharm");
}

private void addTitlePage(Document document) throws DocumentException, UnsupportedEncodingException {
    Paragraph preface = new Paragraph();
    // We add one empty line
    addEmptyLine(preface, 1);
    // Lets write a big header
    preface.add(new Paragraph(mContext.getResources().getString(R.string.report_about_title) + mPdfTitle, catFont));

    addEmptyLine(preface, 1);
    // Will create: Report generated by: _name, _date
    preface.add(new Paragraph(
            mContext.getResources().getString(R.string.report_generated_title) +
                    mContext.getResources().getString(R.string.app_name) + ", " + new Date(), smallBold));

    addEmptyLine(preface, 1);

    preface.add(new Paragraph(mCost, smallBold));

    addEmptyLine(preface, 3);

    document.add(preface);

    createTable(document);
}

private void createTable(Document document) throws DocumentException, UnsupportedEncodingException {
    PdfPTable table = new PdfPTable(4);

    PdfPCell c1 = new PdfPCell(new Phrase(mContext.getResources().getString(R.string.search_results_CatName), catFont));
    c1.setHorizontalAlignment(Element.ALIGN_CENTER);
    table.addCell(c1);

    c1 = new PdfPCell(new Phrase(mContext.getResources().getString(R.string.search_results_Cost), catFont));
    c1.setHorizontalAlignment(Element.ALIGN_CENTER);
    table.addCell(c1);

    c1 = new PdfPCell(new Phrase(mContext.getResources().getString(R.string.search_results_Distance), catFont));
    c1.setHorizontalAlignment(Element.ALIGN_CENTER);
    table.addCell(c1);

    c1 = new PdfPCell(new Phrase(mContext.getResources().getString(R.string.search_results_Note), catFont));
    c1.setHorizontalAlignment(Element.ALIGN_CENTER);
    table.addCell(c1);

    table.setHeaderRows(1);

    for (int i = 0; i < mSearchResult.size(); i++) {
        table.addCell(new PdfPCell(new Phrase(mSearchResult.get(i).getCatName(), catFont)));
        table.addCell(new PdfPCell(new Phrase(mSearchResult.get(i).getCost(), catFont)));
        table.addCell(new PdfPCell(new Phrase(mSearchResult.get(i).getDistance(), catFont)));
        table.addCell(new PdfPCell(new Phrase(mSearchResult.get(i).getNote(), catFont)));
    }
    document.add(table);
}

private void addEmptyLine(Paragraph paragraph, int number) {
    for (int i = 0; i < number; i++) {
        paragraph.add(new Paragraph(" "));
    }
}
}

when i use english words it works fine, but when i use arabic or persian words it shows empty cells in my tables >>

like this: