Columns getting hidden in XSSF Apache POI when using autoSizeColumn

Question

I am trying to export a table as xlsx using Apache POI XSSF. The table has 5 columns.

First row has title block merging 5 columns. In the second row, 5 headings for the table. Remaining rows are data. I want to set width of the column as max width of each heading blocks.

I added a condition and tried mySheet.autoSizeColumn(colnum) when adding the header values so that width of the column will be of same as header data. But when I do that, All the columns are getting hidden on the exported xlsx sheet.

These are the styling elements that I use:

public CellStyle createHeadingStyle(XSSFWorkbook myWorkBook){

      XSSFCellStyle style = myWorkBook.createCellStyle();
      Font fontHeader = myWorkBook.createFont();
      fontHeader.setBoldweight((short)4);
      fontHeader.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
      fontHeader.setFontHeightInPoints((short)8);
      fontHeader.setFontName("GE Inspira Pitch");
      style.setFont(fontHeader);
      style.setAlignment(CellStyle.ALIGN_CENTER); 
      style.setHidden(false);

      //HSSFPalette palette = myWorkBook.getCustomPalette();
      //palette.setColorAtIndex(new Byte((byte) 41), new Byte((byte) 153), new Byte((byte) 204), new Byte((byte) 255));

      style.setFillForegroundColor(new XSSFColor(new java.awt.Color(41,153,204,255)));
      style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);  
    return style;
}

public CellStyle createTitleStyle(XSSFWorkbook myWorkBook){

    CellStyle style = myWorkBook.createCellStyle();
    Font fontHeader = myWorkBook.createFont();
    fontHeader.setBoldweight((short)5);
    fontHeader.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
    fontHeader.setFontHeightInPoints((short)10);
    fontHeader.setColor(HSSFColor.RED.index);
    fontHeader.setFontName("GE Inspira Pitch"); 
    style.setFont(fontHeader);
    style.setAlignment(CellStyle.ALIGN_CENTER); 
    style.setWrapText(true);
    style.setHidden(false);
    return style;
}
public CellStyle createDataStyle(XSSFWorkbook myWorkBook){

     CellStyle style = myWorkBook.createCellStyle();
     Font font = myWorkBook.createFont();
     font.setFontName("GE Inspira Pitch");
     font.setFontHeightInPoints((short)10);
     style.setFont(font);
     style.setAlignment(CellStyle.ALIGN_RIGHT);
     style.setHidden(false);
     return style;
}

This is the code block for creating xlsx:

titleLenght = 2;
cell1.setCellValue(excelTitle);
cell1.setCellStyle(titleCellStyle);
boolean headerStyle = true;
for (int j = 0; j < list.size(); j++) {
    Row row = mySheet.createRow(j+2+titleLength);
    List<String> l2= list.get(j);
    for(int k=0; k<l2.size(); k++)
    {
        Cell cell = row.createCell(k);
        cell.setCellValue(l2.get(k));
        if(headerStyle){
mySheet.autoSizeColumn(k);
cell.setCellStyle(headingCellStyle);
        }else{
cell.setCellStyle(dataCellStyle);
        }
    } 
    headerStyle = false;
}

Answer 1

I made the following change to the code and it worked.

titleLenght = 2;
cell1.setCellValue(excelTitle);

boolean headerStyle = true;
for (int j = 0; j < list.size(); j++) {
    Row row = mySheet.createRow(j+2+titleLength);
    List<String> l2= list.get(j);
    for(int k=0; k<l2.size(); k++)
    {
        Cell cell = row.createCell(k);
        cell.setCellValue(l2.get(k));
        if(headerStyle){
            **cell.setCellStyle(headingCellStyle);
            int origColWidth = mySheet.getColumnWidth(k);
            mySheet.autoSizeColumn(k);
            // Making sure col width is not going less than the header width
            if (origColWidth > mySheet.getColumnWidth(k)) {
                mySheet.setColumnWidth(k, origColWidth);
            }**
        }else{
            cell.setCellStyle(dataCellStyle);
        }
    }   
    headerStyle = false;
}


// Set title style element at last so the first column will not take
// width of title field
cell1.setCellStyle(titleCellStyle);

In my previous code, for the header, autoSizeColumn(K) was returning zero since there is no style associated to it. To be specific no font was assigned since I set used autoSizeColumn(k) before setting style. Hence the width was getting returned as zero. This made all the columns getting hidden.

Now I have added a condition in such a way that width wont become zero at any case. I have moved the title styling to end so that It don't affect the width of the first header column.

Conclusion:

1. Create Cell
2. Set value and Set Style
3. Set autoColumnSize or calculate column width