In order to get PHPExcel http://www.codeplex.com/PHPExcel working with CodeIgniter, there are a few steps you must take to ensure compatibility with CodeIgniter’s naming standards.

1: Class names must match the file names. PHPExcel has a few files(such as PHPExcel/IOFactory.php) that have names like PHPExcel_IOFactory. Change these names by removing the “PHPExcel_” part. These constructors in these files must be public in order for CI to access them.

2. To load a library like the IOFactory, simply say:
$this->load->library(‘PHPExcel/iofactory’);

An simple use case of PHPExcel would look like:

$this->load->library(‘phpexcel’);
$this->load->library(‘PHPExcel/iofactory’);

$objPHPExcel = new PHPExcel();
$objPHPExcel->getProperties()->setTitle(“title”)
            ->setDescription(“description”);
               
// Assign cell values
$objPHPExcel->setActiveSheetIndex(0);
$objPHPExcel->getActiveSheet()->setCellValue(‘A1’, ‘cell value here’);

// Save it as an excel 2003 file
$objWriter = IOFactory::createWriter($objPHPExcel, ‘Excel5’);
$objWriter->save(“nameoffile.xls”);