Ane lagi belajar Framework CI tiba2 nemu error kegni gan saat mau bikin tambah ke keranjang .
jadi ketika sudah submit , malah tidak ada konten yang tampil dan data yang sudah disubmit juga tidak ada didalam db nya gan.

Mohon pencerahannya gan .
controllernya :

<?php

if (!defined('BASEPATH')) exit('No direct script access allowed');



class Shopping extends CI_Controller {



 public function __construct()

 {

 parent::__construct();

 $this->load->library('cart');

 $this->load->model('keranjang_model');

 }



 public function index()

 {

 $kategori=($this->uri->segment(3))?$this->uri->segment(3):0;

 $data['produk'] = $this->keranjang_model->get_produk_kategori($kategori);

 $data['kategori'] = $this->keranjang_model->get_kategori_all();

 $this->load->view('front/header',$data);

    $this->load->view('front/navbar',$data);

 $this->load->view('shopping/tampil_cart',$data);

 $this->load->view('front/footer');

 }

 public function tampil_cart()

 {

 $data['kategori'] = $this->keranjang_model->get_kategori_all();

 $this->load->view('front/header',$data);

    $this->load->view('front/navbar',$data);

 $this->load->view('shopping/tampil_cart',$data);

 $this->load->view('front/footer');

 }



 public function check_out()

 {

 $data['kategori'] = $this->keranjang_model->get_kategori_all();

    $this->load->view('front/header',$data);

    $this->load->view('front/navbar',$data);

 $this->load->view('shopping/check_out',$data);

 $this->load->view('front/footer');

 }



 function tambah()

 {

 $data_produk= array('id' => $this->input->post('id'),

 'judul_produk' => $this->input->post('judul_produk'),

 'harga' => $this->input->post('harga'),

 'foto' => $this->input->post('foto'),

 'qty' =>$this->input->post('qty')

 );

 $this->cart->insert($data_produk);

 redirect('shopping');

 }



 function hapus($rowid)

 {

 if ($rowid=="all")

 {

 $this->cart->destroy();

 }

 else

 {

 $data = array('rowid' => $rowid,

     'qty' =>0);

 $this->cart->update($data);

 }

 redirect('shopping/tampil_cart');

 }



 function ubah_cart()

 {

 $cart_info = $_POST['cart'] ;

 foreach( $cart_info as $id => $cart)

 {

 $rowid = $cart['rowid'];

 $harga = $cart['harga'];

 $foto = $cart['foto'];

 $amount = $price * $cart['qty'];

 $qty = $cart['qty'];

 $data = array('rowid' => $rowid,

 'harga' => $harga,

 'foto' => $foto,

 'amount' => $amount,

 'qty' => $qty);

 $this->cart->update($data);

 }

 redirect('shopping/tampil_cart');

 }



 public function proses_order()

 {

 //-------------------------Input data pelanggan--------------------------

 $data_pelanggan = array('nama' => $this->input->post('nama'),

 'email' => $this->input->post('email'),

 'alamat' => $this->input->post('alamat'),

 'telp' => $this->input->post('telp'));

 $id_pelanggan = $this->keranjang_model->tambah_pelanggan($data_pelanggan);

 //-------------------------Input data order------------------------------

 $data_order = array('tanggal' => date('Y-m-d'),

     'pelanggan' => $id_pelanggan);

 $id_order = $this->keranjang_model->tambah_order($data_order);

 //-------------------------Input data detail order-----------------------

 if ($cart = $this->cart->contents())

 {

 foreach ($cart as $item)

 {

 $data_detail = array('order_id' =>$id_order,

 'produk' => $item['id'],

 'qty' => $item['qty'],

 'harga' => $item['price']);

 $proses = $this->keranjang_model->tambah_detail_order($data_detail);

 }

 }

 //-------------------------Hapus shopping cart--------------------------

 $this->cart->destroy();

 $data['kategori'] = $this->keranjang_model->get_kategori_all();

 $this->load->view('themes/header',$data);

 $this->load->view('shopping/sukses',$data);

 $this->load->view('themes/footer');

 }

}

?>

Model nya : 

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');



class Keranjang_model extends CI_Model {



 public function get_produk_all()

 {

 $query = $this->db->get('produk');

 return $query->result_array();

 }



 public function get_produk_kategori($kategori)

 {

 if($kategori>0)

 {

 $this->db->where('kategori',$kategori);

 }

 $query = $this->db->get('produk');

 return $query->result_array();

 }



 public function get_kategori_all()

 {

 $query = $this->db->get('kategori');

 return $query->result_array();

 }



 public  function get_produk_id($id)

 {

 $this->db->select('produk.*,judul_kategori');

 $this->db->from('produk');

 $this->db->join('kategori', 'kategori=kategori.id','left');

    $this->db->where('id',$id);

        return $this->db->get();

    }



 public function tambah_order($data)

 {

 $this->db->insert('tbl_order', $data);

 $id = $this->db->insert_id();

 return (isset($id)) ? $id : FALSE;

 }



 public function tambah_detail_order($data)

 {

 $this->db->insert('tbl_detail_order', $data);

 }

}

?>

Views nya :

<h2>Daftar Belanja</h2>

<form action="<?php echo base_url()?>shopping/ubah_cart" method="post" name="frmShopping" id="frmShopping" class="form-horizontal" enctype="multipart/form-data">

<?php

 if ($cart = $this->cart->contents())

 {

 ?>



<table class="table">

<tr id= "main_heading">

<td width="2%">No</td>

<td width="10%">Gambar</td>

<td width="33%">Item</td>

<td width="17%">Harga</td>

<td width="8%">Qty</td>

<td width="20%">Jumlah</td>

<td width="10%">Hapus</td>

</tr>

<?php

// Create form and send all values in "shopping/update_cart" function.

$grand_total = 0;

$i = 1;



foreach ($cart as $item):

$grand_total = $grand_total + $item['subtotal'];

?>

<input type="hidden" name="cart[<?php echo $item['id'];?>][id]" value="<?php echo $item['id'];?>" />

<input type="hidden" name="cart[<?php echo $item['id'];?>][rowid]" value="<?php echo $item['rowid'];?>" />

<input type="hidden" name="cart[<?php echo $item['id'];?>][name]" value="<?php echo $item['name'];?>" />

<input type="hidden" name="cart[<?php echo $item['id'];?>][price]" value="<?php echo $item['price'];?>" />

<input type="hidden" name="cart[<?php echo $item['id'];?>][gambar]" value="<?php echo $item['gambar'];?>" />

<input type="hidden" name="cart[<?php echo $item['id'];?>][qty]" value="<?php echo $item['qty'];?>" />

<tr>

<td><?php echo $i++; ?></td>

<td><img class="img-responsive" src="<?php echo base_url() . 'assets/images/'.$item['gambar']; ?>"/></td>

<td><?php echo $item['name']; ?></td>

<td><?php echo number_format($item['price'], 0,",","."); ?></td>

<td><input type="text" class="form-control input-sm" name="cart[<?php echo $item['id'];?>][qty]" value="<?php echo $item['qty'];?>" /></td>

<td><?php echo number_format($item['subtotal'], 0,",",".") ?></td>

<td><a href="<?php echo base_url()?>shopping/hapus/<?php echo $item['rowid'];?>" class="btn btn-sm btn-danger"><i class="glyphicon glyphicon-remove"></i></a></td>

<?php endforeach; ?>

</tr>

<tr>

<td colspan="3"><b>Order Total: Rp <?php echo number_format($grand_total, 0,",","."); ?></b></td>

<td colspan="4" align="right">

<a data-toggle="modal" data-target="#myModal" class ='btn btn-sm btn-danger'>Kosongkan Cart</a>

<button class='btn btn-sm btn-success'  type="submit">Update Cart</button>

<a href="<?php echo base_url()?>shopping/check_out" class ='btn btn-sm btn-primary'>Check Out</a>

</tr>



</table>

<?php

 }

 else

 {

 echo "<h3>Keranjang Belanja masih kosong</h3>";

 }

?>

</form>





  <!-- Modal Penilai -->

  <div class="modal fade" id="myModal" role="dialog">

    <div class="modal-dialog modal-md">

      <!-- Modal content-->

      <div class="modal-content">

      <form method="post" action="<?php echo base_url()?>shopping/hapus/all">

        <div class="modal-header">

          <button type="button" class="close" data-dismiss="modal">×</button>

          <h4 class="modal-title">Konfirmasi</h4>

        </div>

        <div class="modal-body">

 Anda yakin mau mengosongkan Shopping Cart?



        </div>

        <div class="modal-footer">

          <button type="button" class="btn btn-sm btn-primary" data-dismiss="modal">Tidak</button>

          <button type="submit" class="btn btn-sm btn-default">Ya</button>

        </div>



        </form>

      </div>



    </div>

  </div>

  <!--End Modal-->

Mohon berkenaan gan jika dapat ada yang membantu ane ,terimakasih