我想在wordpress中提交表单时创建一个pdf文件。 我使用的是FDPF，代码是
<?php
/* Template Name: FORM TEST */
get_header();
/*** USE THE NEW HEADER FUNCTION **/
WpkPageHelper::zn_get_subheader();
if(isset($_POST['confirm'])){
$fullname = $_POST['fullname'];
$fathername = $_POST['fathername'];
$dob = $_POST['dob'];
$wpdb->insert(
'tck_customer',
array(
'name' => $fullname,
'fname' => $fathername
),
array(
'%s',
'%s'
)
);
?>
<?php
ob_start();
require(STYLESHEETPATH.'/fpdf/fpdf.php');
$pdf = new FPDF();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
ob_clean();
flush();
$pdf->Output();
ob_end_flush();
?>
<form>
FORM STUFFS
</form>
但是当我提交代码时，这给了我错误。 错误：
Fatal error: Uncaught exception 'Exception' with message 'FPDF error: Some data has already been output, can't send PDF file (output started at /home4/q0i4l0g2/public_html/tck/wp-content/themes/kallyas/header.php:2)' in /home4/q0i4l0g2/public_html/tck/wp-content/themes/kallyas-child/fpdf/fpdf.php:271 Stack trace: #0 /home4/q0i4l0g2/public_html/tck/wp-content/themes/kallyas-child/fpdf/fpdf.php(1053): FPDF->Error('Some data has a...') #1 /home4/q0i4l0g2/public_html/tck/wp-content/themes/kallyas-child/fpdf/fpdf.php(1000): FPDF->_checkoutput() #2 /home4/q0i4l0g2/public_html/tck/wp-content/themes/kallyas-child/form-test.php(33): FPDF->Output() #3 /home4/q0i4l0g2/public_html/tck/wp-includes/template-loader.php(89): include('/home4/q0i4l0g2...') #4 /home4/q0i4l0g2/public_html/tck/wp-blog-header.php(16): require_once('/home4/q0i4l0g2...') #5 /home4/q0i4l0g2/public_html/tck/index.php(17): require('/home4/q0i4l0g2...') #6 {main} thrown in /home4/q0i4l0g2/public_html/tck/wp-content/themes/kallyas-child/fpdf/fpdf.php on line 271
我该如何解决这个问题？