[php] How to center the text in PHPExcel merged cell

How to center text "test"?

This is my code:

<?php
    /** Error reporting */
    error_reporting(E_ALL);
    ini_set('display_errors', TRUE);
    ini_set('display_startup_errors', TRUE);
    date_default_timezone_set('Europe/London');

    /** Include PHPExcel */
    require_once '../Classes/PHPExcel.php';

    $objPHPExcel = new PHPExcel();
    $sheet = $objPHPExcel->getActiveSheet();
    $sheet->setCellValueByColumnAndRow(0, 1, "test");
    $sheet->mergeCells('A1:B1');
    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
    $objWriter->save("test.xlsx");

Output Excel document:

<?php
    /** Error reporting */
    error_reporting(E_ALL);
    ini_set('display_errors', TRUE);
    ini_set('display_startup_errors', TRUE);
    date_default_timezone_set('Europe/London');

    /** Include PHPExcel */
    require_once '../Classes/PHPExcel.php';

    $objPHPExcel = new PHPExcel();
    $sheet = $objPHPExcel->getActiveSheet();
    $sheet->setCellValueByColumnAndRow(0, 1, "test");
    $sheet->mergeCells('A1:B1');
    $sheet->getActiveSheet()->getStyle('A1:B1')->getAlignment()->setHorizontal(PHPExcel_Style_Alignment::HORIZONTAL_CENTER);
    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
    $objWriter->save("test.xlsx");
?>

The solution is to set the cell style through this function:

$sheet->getStyle('A1')->getAlignment()->applyFromArray(
    array('horizontal' => PHPExcel_Style_Alignment::HORIZONTAL_CENTER,)
);

Full code

<?php
/** Error reporting */
error_reporting(E_ALL);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);
date_default_timezone_set('Europe/London');

/** Include PHPExcel */
require_once '../Classes/PHPExcel.php';

$objPHPExcel = new PHPExcel();
$sheet = $objPHPExcel->getActiveSheet();
$sheet->setCellValueByColumnAndRow(0, 1, "test");
$sheet->mergeCells('A1:B1');
$sheet->getStyle('A1')->getAlignment()->applyFromArray(
    array('horizontal' => PHPExcel_Style_Alignment::HORIZONTAL_CENTER,)
);
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
$objWriter->save("test.xlsx");

We can also set the vertical alignment with using this way

$style_cell = array(
   'alignment' => array(
       'horizontal' => PHPExcel_Style_Alignment::HORIZONTAL_CENTER,
       'vertical' => PHPExcel_Style_Alignment::VERTICAL_CENTER,
   ) 
); 

with this cell set the vertically aligned into the middle.

When using merged columns, I got it centered by using PHPExcel_Style_Alignment::HORIZONTAL_CENTER_CONTINUOUS instead of PHPExcel_Style_Alignment::HORIZONTAL_CENTER