使用Apache在下一行中插入数据

Question

我正在尝试使用Android Studio中的Apache POI将数据输入到excel电子表格的下一行。目前，我的应用程序是关于扫描QR码然后基于QR码的值，它将值传输到excel。我设法只插入excel中的第一行。但是，它只是在扫描另一个QR码后用新值替换。所以我需要修改一些代码，以便每次扫描时它都会插入到一个新行中。需要一些指南。

当前代码：

private static boolean saveExcelFile(Context context, String fileName, String result) {

        // check if available and not read only
        if (!isExternalStorageAvailable() || isExternalStorageReadOnly()) {
            Log.e(TAG, "Storage not available or read only");
            return false;
        }

        boolean success = false;

        //New Workbook
        Workbook wb = new HSSFWorkbook();

        Cell c = null;

        //Cell style for header row
        CellStyle cs = wb.createCellStyle();
        cs.setFillForegroundColor(HSSFColor.LIME.index);
        cs.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);



        //New Sheet
        Sheet sheet1 = null;
        sheet1 = wb.createSheet("Material_List");

        // Generate column headings
        Row row = sheet1.createRow(0);

        c = row.createCell(0);
        c.setCellValue("Material Code");
        c.setCellStyle(cs);

        c = row.createCell(1);
        c.setCellValue("Material Name");
        c.setCellStyle(cs);

        c = row.createCell(2);
        c.setCellValue("Lot Size");
        c.setCellStyle(cs);

        c = row.createCell(3);
        c.setCellValue("Quantity");
        c.setCellStyle(cs);

        sheet1.setColumnWidth(0, (15 * 500));
        sheet1.setColumnWidth(1, (15 * 500));
        sheet1.setColumnWidth(2, (15 * 500));
        sheet1.setColumnWidth(3, (15 * 500));



        //String str = result.getContents();
        //String str = "1000000000 SA241ASDAA 1IKSDKE 200";
        String str = result;
        String[] splited = str.split("\\s+");

        String split_one=splited[0];
        String split_second=splited[1];
        String split_three=splited[2];
        String split_four=splited[3];

        // Generate column headings

            Row row2 = sheet1.createRow(1);

            c = row2.createCell(0);
            c.setCellValue(split_one);

            c = row2.createCell(1);
            c.setCellValue(split_second);

            c = row2.createCell(2);
            c.setCellValue(split_three);

            c = row2.createCell(3);
            c.setCellValue(split_four);



        // Create a path where we will place our List of objects on external storage
        File file = new File(context.getExternalFilesDir(null), fileName);
        FileOutputStream os = null;

        try {
            os = new FileOutputStream(file);
            wb.write(os);
            Log.w("FileUtils", "Writing file" + file);
            success = true;
        } catch (IOException e) {
            Log.w("FileUtils", "Error writing " + file, e);
        } catch (Exception e) {
            Log.w("FileUtils", "Failed to save file", e);
        } finally {
            try {
                if (null != os)
                    os.close();
            } catch (Exception ex) {
            }
        }
        return success;
    }