PHPExcel - creating multiple sheets by iteration

When you first instantiate the $objPHPExcel, it already has a single sheet (sheet 0); you're then adding a new sheet (which will become sheet 1), but setting active sheet to sheet $i (when $i is 0)... so you're renaming and populating the original worksheet created when you instantiated $objPHPExcel rather than the one you've just added... this is your title "0".

You're also using the createSheet() method, which both creates a new worksheet and adds it to the workbook... but you're also adding it again yourself which is effectively adding the sheet in two position.

So first iteration, you already have sheet0, add a new sheet at both indexes 1 and 2, and edit/title sheet 0. Second iteration, you add a new sheet at both indexes 3 and 4, and edit/title sheet 1, but because you have the same sheet at indexes 1 and 2 this effectively writes to the sheet at index 2. Third iteration, you add a new sheet at indexes 5 and 6, and edit/title sheet 2, overwriting your earlier editing/titleing of sheet 1 which acted against sheet 2 instead.... and so on

Complementing the coment of @Mark Baker.
Do as follow:

$titles = array('title 1', 'title 2');
$sheet = 0;
foreach($array as $value){
    if($sheet > 0){
        $objPHPExcel->createSheet();
        $sheet = $objPHPExcel->setActiveSheetIndex($sheet);
        $sheet->setTitle("$value");
        //Do you want something more here
    }else{
        $objPHPExcel->setActiveSheetIndex(0)->setTitle("$value");
    }
    $sheet++;
}  

This worked for me. And hope it works for those who need! :)

You dont need call addSheet() method. After creating sheet, it already add to excel. Here i fixed some codes:

    //First sheet
    $sheet = $objPHPExcel->getActiveSheet();

    //Start adding next sheets
    $i=0;
    while ($i < 10) {

      // Add new sheet
      $objWorkSheet = $objPHPExcel->createSheet($i); //Setting index when creating

      //Write cells
      $objWorkSheet->setCellValue('A1', 'Hello'.$i)
                   ->setCellValue('B2', 'world!')
                   ->setCellValue('C1', 'Hello')
                   ->setCellValue('D2', 'world!');

      // Rename sheet
      $objWorkSheet->setTitle("$i");

      $i++;
    }