PHPExcel multiple sheet

<?php
session_start();
error_reporting(E_ALL);

/** PHPExcel */
include 'PHPExcel.php';


include '../../conn.php';
function chappsdatetime($waktu){
    if (isset($waktu)){
    $waktu_bulan= substr($waktu,5,2);
    $bulan_aray= array('Januari','Februari','Maret','April','Mei','Juni','Juli','Agustus','September','Oktober','November','Desember');
    return substr($waktu,8,2)." ".$bulan_aray[$waktu_bulan]." ".substr($waktu,0,4)." ".substr($waktu,11,8);
    }
}

//variabel
$bulan = $_POST['bulan'];
$thn = $_POST['thn'];
$cab = "Semarang";

// Create new PHPExcel object
$objPHPExcel = new PHPExcel();
// Set properties
$objPHPExcel->getProperties()->setCreator("Rifaqu Emprit")
                            ->setLastModifiedBy("Administrator")
                            ->setTitle("Office 2007 XLSX Test Document")
                            ->setSubject("Office 2007 XLSX Test Document")
                            ->setDescription("Laporan Barang Semarang");

//query perulangan sheet menurut jenis barang
$sheet = 0;
$jenis_brg = mysql_query("SELECT nama FROM jenis_barang order by id_brg asc")or die(mysql_error());
while ($nama = mysql_fetch_array($jenis_brg)){

if($sheet>0) $objPHPExcel->createSheet();

$objPHPExcel->setActiveSheetIndex($sheet);
//autosize
$objPHPExcel->getActiveSheet()->getColumnDimension('A')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('B')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('C')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('D')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('E')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('F')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('G')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('H')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('I')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('J')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('K')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('L')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('M')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('N')->setAutoSize(true);





        //query transaksi
        $baris = 6;
        $no = 0;

        $transaksi = mysql_query("SELECT * FROM transaksi where kategori='".$nama['nama']."' and tgl_transaksi like '$thn-$bulan-%'") or die(mysql_error());
        while($m=mysql_fetch_array($transaksi)){

        $no = $no +1;
        $baris = $baris+1;

        $tgl = chappsdatetime($m['tgl_transaksi']);

        //isi
        $objPHPExcel->getActiveSheet()
             ->setCellValue("A$baris", $no)
             ->setCellValue("B$baris", $tgl)
             ->setCellValue("C$baris", $m['masuk'])
             ->setCellValue("D$baris", $m['keluar'])
             ->setCellValue("E$baris", '')
             ->setCellValue("F$baris", $m['harga_beli'])
             ->setCellValue("G$baris", $m['harga_jual'])
             ->setCellValue("H$baris", '=SUM(G'.$baris.'-F'.$baris.')')
             ->setCellValue("I$baris", '=SUM(H'.$baris.'*D'.$baris.')')
             ->setCellValue("J$baris", '=SUM(C'.$baris.'*F'.$baris.')')
             ->setCellValue("K$baris", '=SUM(D'.$baris.'*G'.$baris.')')
             ->setCellValue("L$baris", $m['konsumen'])
             ->setCellValue("M$baris", $m['alamat'])
             ->setCellValue("N$baris", $m['ket']);

            $sharedStyle2 = new PHPExcel_Style();
            $sharedStyle2->applyFromArray(
             array('borders' => array(
             'bottom' => array('style' => PHPExcel_Style_Border::BORDER_THIN),
             'top' => array('style' => PHPExcel_Style_Border::BORDER_THIN),
             'right' => array('style' => PHPExcel_Style_Border::BORDER_MEDIUM),
             'left' => array('style' => PHPExcel_Style_Border::BORDER_MEDIUM)
             ),
             ));

            $objPHPExcel->getActiveSheet()->setSharedStyle($sharedStyle2, "A$baris:N$baris");

            $objPHPExcel->getActiveSheet()->getStyle("A$baris:H$baris")->getFont()->setName('Times');
            $objPHPExcel->getActiveSheet()->getStyle("A$baris:H$baris")->getFont()->setSize(11);

        }

            // Mulai Merge cells Judul
            $objPHPExcel->getActiveSheet()
                         ->mergeCells('A1:N1')
                         ->setCellValue('A1', "LAPORAN TRANSAKSI BAJA RINGAN")
                         ->getStyle('A1')->getAlignment()->setHorizontal(PHPExcel_Style_Alignment::HORIZONTAL_CENTER);

            $objPHPExcel->getActiveSheet()->mergeCells('A2:N2');
            $objPHPExcel->getActiveSheet()->setCellValue('A2', "CV. ANJASA");
            $objPHPExcel->getActiveSheet()->getStyle('A2')->getAlignment()->setHorizontal(PHPExcel_Style_Alignment::HORIZONTAL_CENTER);

            $objPHPExcel->getActiveSheet()->mergeCells('A3:N3');
            $objPHPExcel->getActiveSheet()->setCellValue('A3', "Jln. Tentara Pelajar No. 79");
            $objPHPExcel->getActiveSheet()->getStyle('A3')->getAlignment()->setHorizontal(PHPExcel_Style_Alignment::HORIZONTAL_CENTER);

            $objPHPExcel->getActiveSheet()->mergeCells('A5:N5');
            $objPHPExcel->getActiveSheet()->setCellValue('A5', "Bulan $bulan Cabang $cab");

            $objPHPExcel->getActiveSheet()->getStyle('A1:H1')->getFont()->setName('Times');
            $objPHPExcel->getActiveSheet()->getStyle('A1:H1')->getFont()->setSize(12);
            $objPHPExcel->getActiveSheet()->getStyle('A1:H1')->getFont()->setBold(true);
            $objPHPExcel->getActiveSheet()->getStyle('A2:H2')->getFont()->setName('Times');
            $objPHPExcel->getActiveSheet()->getStyle('A2:H2')->getFont()->setSize(12);
            $objPHPExcel->getActiveSheet()->getStyle('A2:H2')->getFont()->setBold(true);
            $objPHPExcel->getActiveSheet()->getStyle('A3:H3')->getFont()->setName('Times');
            $objPHPExcel->getActiveSheet()->getStyle('A3:H3')->getFont()->setSize(12);
            $objPHPExcel->getActiveSheet()->getStyle('A3:H3')->getFont()->setBold(true);
            $objPHPExcel->getActiveSheet()->getStyle('A5:H5')->getFont()->setName('Times');
            $objPHPExcel->getActiveSheet()->getStyle('A5:H5')->getFont()->setSize(12);
            $objPHPExcel->getActiveSheet()->getStyle('A5:H5')->getFont()->setBold(true);

    //pembuatan sheet
    $objPHPExcel->getActiveSheet()
                ->SetCellValue('A7', 'No.')
                ->SetCellValue('B7', 'Tangal Transaksi')
                ->SetCellValue('C7', 'Pembelian')
                ->SetCellValue('D7', 'Penjualan')
                ->SetCellValue('E7', 'Stock Barang')
                ->SetCellValue('F7', 'Harga Beli')
                ->SetCellValue('G7', 'Harga Jual')
                ->SetCellValue('H7', 'Laba Jual')
                ->SetCellValue('I7', 'Total Laba Penjualan')
                ->SetCellValue('J7', 'Total Pembelian')
                ->SetCellValue('K7', 'Total Harga Jual')
                ->SetCellValue('L7', 'Konsumen')
                ->SetCellValue('M7', 'Alamat')
                ->SetCellValue('N7', 'Keterangan');

    //Membuat Garis atau tabel
        $sharedStyle1 = new PHPExcel_Style();
        $sharedStyle1->applyFromArray(
        array('borders' => array(
         'bottom' => array('style' => PHPExcel_Style_Border::BORDER_THIN),
         'top' => array('style' => PHPExcel_Style_Border::BORDER_THIN),
         'right' => array('style' => PHPExcel_Style_Border::BORDER_MEDIUM),
         'left' => array('style' => PHPExcel_Style_Border::BORDER_MEDIUM)
        ),
        ));

    // Rename sheet
    $objPHPExcel->getActiveSheet()->setTitle($nama['nama']);

    $sheet = $sheet+1;
}
    // Set active sheet index to the first sheet, so Excel opens this as the first sheet
    $objPHPExcel->setActiveSheetIndex(0);

    // Redirect output to a client’s web browser (Excel5)
    header('Content-Type: application/vnd.ms-excel');
    header('Content-Disposition: attachment;filename="Laporan Transaksi Barang-'.$bulan.$thn.'.xls"');
    header('Cache-Control: max-age=0');

    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5');
    $objWriter->save('php://output');
    exit;