setting cell style not working - apache-poi

Question

i'm working with apache poi and XLSX file. i use xssf classes to dynamically create a spreadsheet.
i'd like to set cell's style in a for loop, but it doesn't seem to work...here's my code :
for(int i=1;i<=gc.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);i++,gc.add(GregorianCalendar.DATE, 1),righe++){
Row r = foglio.createRow(righe);
if(getDayOfWeek(gc)== 6 || getDayOfWeek(gc) == 7){
XSSFCellStyle cs1 = wb.createCellStyle();
cs1.setFillBackgroundColor(IndexedColors.YELLOW.getIndex());
cs1.setFillPattern(CellStyle.SOLID_FOREGROUND);
XSSFFont f = wb.createFont();
f.setBold(true);
f.setColor(IndexedColors.RED.getIndex());
cs1.setFont(f);
Cell c1 = r.createCell(0);
c1.setCellValue(cost.getGiorni().get(getDayOfWeek(gc)-1).getNomeGiorno());
c1.setCellStyle(cs1);
Cell c2 = r.createCell(1);
c2.setCellValue(i);
c2.setCellStyle(cs1);
}
r.createCell(0).setCellValue(cost.getGiorni().get(getDayOfWeek(gc)-1).getNomeGiorno());
r.createCell(1).setCellValue(i);
...this i just a portion of the code...
i can't understand why is not working. Seems like the cellstyle is ignored or overwrited....
any clue ?

Answer 1

CellStyles are per-workbook, and there's a hard limit that Excel imposes on the numbers that a file is allowed to have, so you need to make sure you create the cell style once outside the loop.
Your code would then look something like:
XSSFCellStyle cs1 = wb.createCellStyle();
cs1.setFillBackgroundColor(IndexedColors.YELLOW.getIndex());
cs1.setFillPattern(CellStyle.SOLID_FOREGROUND);
XSSFFont f = wb.createFont();
f.setBold(true);
f.setColor(IndexedColors.RED.getIndex());
cs1.setFont(f);
for(int i=1;i<=gc.getActualMaximum(GregorianCalendar.DAY_OF_MONTH) i++,gc.add(GregorianCalendar.DATE, 1),righe++){
Row r = foglio.createRow(righe);
if(getDayOfWeek(gc)== 6 || getDayOfWeek(gc) == 7){
Cell c1 = r.createCell(0);
c1.setCellValue(cost.getGiorni().get(getDayOfWeek(gc)-1).getNomeGiorno());
c1.setCellStyle(cs1);
Cell c2 = r.createCell(1);
c2.setCellValue(i);
c2.setCellStyle(cs1);
}
}
If you're having issues with the styling not looking quite as you expect, the best option is to style a cell as you want it in Excel, save the file, read that into POI, and review the cell style that Excel wrote. Sometimes, Excel can do some strange things that take some getting used to, so check what it does to work out what you need to be doing!

Answer 2

You can use Following method, perhaps this will resolve your problem.
public static void setCellColorAndFontColor(XSSFCell cell, IndexedColors FGcolor, IndexedColors FontColor ){
XSSFWorkbook wb = cell.getRow().getSheet().getWorkbook();
CellStyle style = wb.createCellStyle();
XSSFFont font = wb.createFont();
font.setBold(true);
font.setColor(FontColor.getIndex());
style.setFont(font);
style.setFillForegroundColor(FGcolor.getIndex());
style.setFillPattern(CellStyle.SOLID_FOREGROUND);
cell.setCellStyle(style);
}
When you are calling this method the way should be like
setCellColorAndFontColor(cell, IndexedColors.BLACK, IndexedColors.WHITE);
will create bold & white font text color with black cell background color in the sheet.

Answer 3

I think the
.setFillPattern(CellStyle.SOLID_FOREGROUND);
got changed to
.setFillPattern(FillPatternType.SOLID_FOREGROUND);
this works for me:
//design settings for header row
Font headerFont = wb.createFont();
headerFont.setColor(IndexedColors.WHITE.getIndex());
CellStyle headerCellStyle = wb.createCellStyle();
headerCellStyle.setFont(headerFont);
headerCellStyle.setAlignment(HorizontalAlignment.CENTER);
headerCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
headerCellStyle.setFillForegroundColor(IndexedColors.BLACK.getIndex());
headerCellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);