Problem: How to put button "add to cart" in Home page!

Notice: Undefined index: product_id in C:\xampp\htdocs\qsmart\catalog\controller\module\cart.php on line 57Notice: Undefined index: quantity in C:\xampp\htdocs\qsmart\catalog\controller\module\cart.php on line 57

If you are wanting to use the ajax animation stuff with it, you will have problems with w3 validation as it triggers on <a id="add_to_cart" which means each add to cart button would have the same id.
Same with the form id of "category_product".

But anyway, if you just want it to submit normal POST style, this worked for me (assuming you added the href2 and product_id to the product array in the category controller):

<?php
class ControllerCommonHome extends Controller {
public function index() {
$this->language->load('common/home');

$this->document->title = sprintf($this->language->get('title'), $this->config->get('config_store'));
$this->document->description = $this->config->get('config_meta_description');

$this->data['text_gift'] = $this->language->get('text_gift');
$this->data['text_model'] = $this->language->get('text_model');
$this->data['text_qty'] = $this->language->get('text_qty');

$this->document->breadcrumbs = array();

$this->document->breadcrumbs[] = array(
'href' => $this->url->http('common/home'),
'text' => $this->language->get('text_home'),
'separator' => FALSE
);

$this->data['heading_title'] = sprintf($this->language->get('heading_title'), $this->config->get('config_store'));
$this->data['welcome'] = html_entity_decode($this->config->get('config_welcome_' . $this->language->getId()));

$this->data['text_latest'] = $this->language->get('text_latest');
$this->data['text_bestseller'] = $this->language->get('text_bestseller');
$this->data['text_special'] = $this->language->get('text_special');
$this->data['text_price'] = $this->language->get('text_price');

$this->data['button_add_to_cart'] = $this->language->get('button_add_to_cart');

$this->data['action'] = $this->url->http('checkout/cart');

$this->load->model('catalog/product');
$this->load->model('catalog/review');
$this->load->model('tool/seo_url');
$this->load->helper('image');

$this->data['products'] = array();

foreach ($this->model_catalog_product->getLatestProducts(10) as $result) {
if ($result['image']) {
$image = $result['image'];
} else {
$image = 'no_image.jpg';
}


$rating = $this->model_catalog_review->getAverageRating($result['product_id']);

$special = FALSE;

$discount = $this->model_catalog_product->getProductDiscount($result['product_id']);

if ($discount) {
$price = $this->currency->format($this->tax->calculate($discount, $result['tax_class_id'], $this->config->get('config_tax')));
} else {
$price = $this->currency->format($this->tax->calculate($result['price'], $result['tax_class_id'], $this->config->get('config_tax')));

$special = $this->model_catalog_product->getProductSpecial($result['product_id']);

if ($special) {
$special = $this->currency->format($this->tax->calculate($special, $result['tax_class_id'], $this->config->get('config_tax')));
}
}
if(isset($result['gift'])){
$this->data['products'][] = array(
'product_id' => $result['product_id'],
'name' => $result['name'],
'model' => $result['model'],
'description' => $result['description'],
'meta_description' => $result['meta_description'],
'rating' => $rating,
'stars' => sprintf($this->language->get('text_stars'), $rating),
'thumb' => image_resize($image, $this->config->get('config_image_product_width'), $this->config->get('config_image_product_height')),
'zoom' => image_resize($image, $this->config->get('config_image_thumb_width'), $this->config->get('config_image_thumb_height')),
'price' => $price,
'special' => $special,
'gift' => $result['gift'],
'date_start' => $result['date_start'],
'date_end' => $result['date_end'],
'href' => $this->model_tool_seo_url->rewrite($this->url->http('product/product&product_id=' . $result['product_id'])),
'href2' => $this->url->http('checkout/cart')
);
}else{
$this->data['products'][] = array(
'product_id' => $result['product_id'],
'name' => $result['name'],
'model' => $result['model'],
'description' => $result['description'],
'meta_description' => $result['meta_description'],
'rating' => $rating,
'stars' => sprintf($this->language->get('text_stars'), $rating),
'thumb' => image_resize($image, $this->config->get('config_image_product_width'), $this->config->get('config_image_product_height')),
'price' => $price,
'special' => $special,
'href' => $this->model_tool_seo_url->rewrite($this->url->http('product/product&product_id=' . $result['product_id'])),
'href2' => $this->url->http('checkout/cart')
);
}

}

if (!$this->config->get('config_customer_price')) {
$this->data['display_price'] = TRUE;
} elseif ($this->customer->isLogged()) {
$this->data['display_price'] = TRUE;
} else {
$this->data['display_price'] = FALSE;
}
$this->id = 'content';
$this->template = $this->config->get('config_template') . 'common/home.tpl';
$this->layout = 'common/layout';

$this->render();
}
}
?>

Notice: Undefined index: product_id in C:\xampp\htdocs\qsmart\catalog\controller\module\cart.php on line 57
Notice: Undefined index: quantity in C:\xampp\htdocs\qsmart\catalog\controller\module\cart.php on line 57

<form action="<?php echo $products[$j]['href2']; ?>" method="post" enctype="multipart/form-data" id="category_product_<?php echo $products[$j]['product_id'];?>">
<td style="align: left; width: 70%">
<div style="background: #F7F7F7; border: 1px solid #DDDDDD; padding: 10px;"><?php echo $text_qty; ?>
<input type="text" name="quantity" size="3" value="1" />
</td>
<td>
<a onclick="$('#category_product_<?php echo $products[$j]['product_id'];?>').submit();" id="category_product_<?php echo $products[$j]['product_id']; ?>" class="button add2cart"><span><?php echo $button_add_to_cart; ?></span></a></div>
<input type="hidden" name="product_id" value="<?php echo $products[$j]['product_id']; ?>" />
</td>
</form>