Also, you seem to be settings string as values to the cell. You need to set them as numbers if you want to use a numeric function on them.
On Wednesday 09 August 2006 19:14, Blanchette, Nicole wrote: > The Jakarta page with info on modifying spreadsheets (the HOWTO for HSSF) > said that you had to remove the cells and then put them back in... which > you're right, it does seem weird, and it may not be right for this case. > But I just tried fixing that, and it didn't change my results at all. I'm > still getting the same error message, and the same result is popping up. > > > -----Original Message----- > From: Avik Sengupta [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 09, 2006 9:41 AM > To: [email protected] > Cc: Blanchette, Nicole > Subject: Re: stuck on formula evaluations > > > What's that delete cell/ create cell thing ... dont understand why you need > to > do it, but I dont think the formula is going to work if you delete the > cells > that it refers to... > > On Wednesday 09 August 2006 18:57, Blanchette, Nicole wrote: > > Hi, > > I'm trying to read in an existing worksheet with formulas, modify it, and > > then read the results after the formulas have been calculated (for a > > GUI). I have the scratchpad jar and a recent version of the poi. I can't > > seem to evaluate the formula though, and then read back the result. I've > > been testing with a very simple worksheet and program. I've read the > > Formula Evaluation page on the Jakarta website several times, and still > > can't figure it out... Any sort of help would be greatly appreciated. > > > > My error message reads: > > java.lang.NullPointerException > > at > > org.apache.poi.hssf.usermodel.HSSFFormulaEvaluator.internalEvaluate(HSSFFor > > >m ulaEvaluator.java:281) > > at > > org.apache.poi.hssf.usermodel.HSSFFormulaEvaluator.evaluate(HSSFFormulaEval > > >u ator.java:181) > > at testexcel.Frame1.jbInit(Frame1.java:175) > > at testexcel.Frame1.<init>(Frame1.java:81) > > at testexcel.testexcel.<init>(testexcel.java:20) > > at testexcel.testexcel.main(testexcel.java:50) > > > > relevant part of my code: > > > > import org.apache.poi.hssf.usermodel.HSSFCell; > > import org.apache.poi.hssf.usermodel.HSSFRow; > > import org.apache.poi.hssf.usermodel.HSSFSheet; > > import org.apache.poi.hssf.usermodel.HSSFWorkbook; > > import org.apache.poi.hssf.usermodel.HSSFFormulaEvaluator; > > > > > > POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream("file > > path")); > > > FileOutputStream stream = new FileOutputStream("new file path"); > > HSSFWorkbook wb = new HSSFWorkbook(fs); > > HSSFSheet sheet = wb.getSheetAt(0); > > HSSFFormulaEvaluator evaluator = new HSSFFormulaEvaluator(sheet, > > wb); > > wb.write(stream); > > > > //get necessary rows & cells > > HSSFRow row1 = sheet.getRow(1); > > HSSFRow row2 = sheet.getRow(2); > > HSSFCell cell1 = row1.getCell((short) 0); > > HSSFCell cell2 = row2.getCell((short) 0); > > > > //remove cells that you're writing to > > row1.removeCell(cell1); > > row2.removeCell(cell2); > > > > //create new cells to insert > > HSSFCell cell5 = row1.createCell((short)0); > > HSSFCell cell6 = row2.createCell((short)0); > > HSSFCell cell7 = row1.getCell((short)1); > > HSSFCell cell8 = row2.getCell((short)1); > > > > //set values of cells > > cell5.setCellValue("5"); //these values actually come from user > > input, from textfield > > cell6.setCellValue("1"); > > cell7.setCellValue("bob"); > > > > //write to workbook > > wb.write(stream); > > stream.close(); > > > > //evaluate simple formula in cell8 (=cell5 - cell6) > > HSSFFormulaEvaluator.CellValue cellValue = > > evaluator.evaluate(cell8); > > String a = String.valueOf(cellValue); //value must be string to > > read out in textfield > > > > //retrieve values > > jLabel6.setText(cell7.getStringCellValue()); > > jTextField3.setText(a); //these text fields are showing up blank > > when I run it > > > > > > I'm new to the list, new to poi, and new to Java, so my apologies if this > > has already been gone over a bunch of times or if I ask a lot of stupid > > questions. > > Thanks, > > Nicole > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > Mailing List: http://jakarta.apache.org/site/mail2.html#poi > > The Apache Jakarta Poi Project: http://jakarta.apache.org/poi/ --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] Mailing List: http://jakarta.apache.org/site/mail2.html#poi The Apache Jakarta Poi Project: http://jakarta.apache.org/poi/
