Custom 404 error message not working in codeigniter - php

Question

When I access the wrong function in my controller, a 404 error page is working well. But, when i access url like 'http://example.com/model/detail/116', which 116 is wrong number [are not in the database], my 404 error page not working.
I have this code in my controller:
public function detail()
{
$id['id_galeri'] = $this->uri->segment(3);
$detail = $this->app_model->getSelectedData("tbl_galeri",$id);
foreach($detail->result() as $d)
{
$bc['jdl'] = "View";
$bc['id_galeri'] = $d->id_galeri;
$bc['nama'] = $d->nama;
$bc['foto'] = $d->foto;
$bc['deskripsi'] = $d->deskripsi;
$bc['stts_input'] = "deskripsi";
}
if($this->uri->segment(3) == '' && $id['id_galeri'] == FALSE)
{
$segment_url = 0;
}else{
if(!is_numeric($this->uri->segment(3)) || !is_string($this->uri->segment(3))){
redirect('404');
}else{
$segment_url = $this->uri->segment(3);
}
}
$this->load->view('frontend/global/bg_top');
$this->load->view('frontend/page/bg_view_model',$bc);
$this->load->view('frontend/global/bg_footer');
}
Sorry for my bad english, please help :-)
Thank you..

Answer 1

Instead of:
redirect('404');
try using CodeIgniter's native:
show_404('page');
EDIT
Try this code, a bit cleaned up and the checks are done before they're saved for views use.
public function detail()
{
$id['id_galeri'] = $this->uri->segment(3);
// Check if the supplied ID is numeric in the first place
if ( ! is_numeric($id['id_galeri']))
{
show_404($this->uri->uri_string());
}
// Get the data
$detail = $this->app_model->getSelectedData("tbl_galeri",$id);
// Check if any records returned
if (count($detail->result()) === 0)
{
show_404($this->uri->uri_string());
}
foreach($detail->result() as $d)
{
$bc['jdl'] = "View";
$bc['id_galeri'] = $d->id_galeri;
$bc['nama'] = $d->nama;
$bc['foto'] = $d->foto;
$bc['deskripsi'] = $d->deskripsi;
$bc['stts_input'] = "deskripsi";
}
/**
* Here do whatever you want with the $segment_url which doesn't seem to be
* used in your code
*/
$this->load->view('frontend/global/bg_top');
$this->load->view('frontend/page/bg_view_model',$bc);
$this->load->view('frontend/global/bg_footer');
}