Styjun

I am using a Custom post type and integrated woocommerce on it, I am able to add an add-to-cart button on the pages and can add it to cart, so it works fine

here is my code

class WCCPT_Product_Data_Store_CPT extends WC_Product_Data_Store_CPT 

 /**
 * Method to read a product from the database.
 * @param WC_Product
 */

 public function read( &$product ) ! in_array( $post_object->post_type, array( 'products', 'product' ) ) ) // change birds with your post type
 throw new Exception( __( 'Invalid product.', 'woocommerce' ) );
 

 $id = $product->get_id();

 $product->set_props( array(
 'name' => $post_object->post_title,
 'slug' => $post_object->post_name,
 'date_created' => 0 < $post_object->post_date_gmt ? wc_string_to_timestamp( $post_object->post_date_gmt ) : null,
 'date_modified' => 0 < $post_object->post_modified_gmt ? wc_string_to_timestamp( $post_object->post_modified_gmt ) : null,
 'status' => $post_object->post_status,
 'description' => $post_object->post_content,
 'short_description' => $post_object->post_excerpt,
 'parent_id' => $post_object->post_parent,
 'menu_order' => $post_object->menu_order,
 'reviews_allowed' => 'open' === $post_object->comment_status,
 ) );

 $this->read_attributes( $product );
 $this->read_downloads( $product );
 $this->read_visibility( $product );
 $this->read_product_data( $product );
 $this->read_extra_data( $product );
 $product->set_object_read( true );
 

 /**
 * Get the product type based on product ID.
 *
 * @since 3.0.0
 * @param int $product_id
 * @return bool

add_filter( 'woocommerce_data_stores', 'woocommerce_data_stores' );

function woocommerce_data_stores ( $stores ) 
 $stores['product'] = 'WCCPT_Product_Data_Store_CPT';
 return $stores;


add_filter('woocommerce_product_get_price', 'woocommerce_product_get_price', 10, 2 );
function woocommerce_product_get_price( $price, $product ) 

 $reflector = new ReflectionClass($product);
 $classProperty = $reflector->getProperty('id');
 $classProperty->setAccessible(true);
 $vid_id = $classProperty->getValue($product);
 //$cpt_product_price = get_field('product_specifications', $vid_id); 
 $cpt_product_price = get_field('e-commerce', $vid_id);

 if ($product->get_id() == $vid_id) 
 $price = $cpt_product_price['global']['price'];
 

 return $price;


//add_filter('the_content','rei_add_to_cart_button', 20,1);
/*
function rei_add_to_cart_button($content)
 global $post;
 if ($post->post_type !== 'products') return $content; 
 var_dump($content);


 $cpt_product_price = get_field('product_specifications', get_the_ID());
 //var_dump($cpt_product_price);


 ob_start();
 if ( !empty($cpt_product_price['_price']) ) 
 ?>
 <form action="" method="post">
 <input name="add-to-cart" type="hidden" value="<?php echo $post->ID ?>" />
 <input name="quantity" type="number" value="1" min="1" />
 <input name="submit" type="submit" value="Add to cart" />
 </form>
 <?php
 
 return $content . ob_get_clean();


*/




function rei_add_to_cart_button()
 global $post;
 if ($post->post_type !== 'products') return; 
 //var_dump($content);



 $get_ecommerce = get_field('e-commerce', get_the_ID());
 //var_dump($get_ecommerce);

 $get_ecommerce_price = $get_ecommerce['global']['price'];

 //global

 //price

 //$cpt_product_price = get_field('product_specifications', get_the_ID());


 //var_dump($cpt_product_price);
 //var_dump($cpt_product_price);

 ob_start();
 if ( !empty($get_ecommerce_price) ) 
 ?>
 <form action="" method="post">
 <input name="_gram" type="hidden" value="10">
 <input name="add-to-cart" type="hidden" value="<?php echo $post->ID ?>" />
 <input name="quantity" type="number" value="1" min="1" />
 <input name="submit" type="submit" value="Add to cart" />
 </form>
 <?php
 
 return ob_get_clean();

but now I need to add some custom fields on the product page, a dropdown containing colours "black" and "white", this is just an ordinary dropdown. How can I when I select a value it will display on the cart under the product name

Update 2

Try the following (that normally adds a dropdown in single product pages and save/display the selected value in cart item):

// Frontend: custom select field (dropdown) in product single pages
add_action( 'woocommerce_before_add_to_cart_button', 'fabric_length_product_field' );
function fabric_length_product_field() 
 global $product;

 // Select field
 woocommerce_form_field('fitting_color', array(
 'type' => 'select',
 'class' => array('my-field-class form-row-wide'),
 'label' => __('_fitting_color', 'woocommerce'),
 'required' => true, // or false
 'options' => array(
 '' => __('Select a color', 'woocommerce'),
 'black' => __('Black', 'woocommerce'),
 'white' => __('White', 'woocommerce'),
 ),
 ),'');


// Add "fitting_color" selected value as custom cart item data
add_filter( 'woocommerce_add_cart_item_data', 'add_custom_cart_item_data', 20, 2 );
function add_custom_cart_item_data( $cart_item_data, $product_id )
 if( isset($_POST['fitting_color']) && ! empty($_POST['fitting_color'])) 
 $cart_item_data['fcolor']= array(
 'value' => esc_attr($_POST['fitting_color']),
 'unique_key' => md5( microtime() . rand() ), // <= Make each cart item unique
 );
 
 return $cart_item_data;



// Display custom cart item data in cart and checkout pages
add_filter( 'woocommerce_get_item_data', 'display_custom_cart_item_data', 10, 2 );
function display_custom_cart_item_data( $cart_item_data, $cart_item ) 
 if ( isset( $cart_item['fcolor']['value'] ) )
 $cart_item_data[] = array(
 'name' => __( 'Fitting color', 'woocommerce' ),
 'value' => $cart_item['fcolor']['value'],
 );
 
 return $cart_item_data;

Code goes on function.php file of your active child theme (or active theme). It should works.

For save/display on order (and display on email notifications), you will use:

// Save chosen slelect field value to each order item as custom meta data and display it everywhere
add_action('woocommerce_checkout_create_order_line_item', 'save_order_item_product_fitting_color', 10, 4 );
function save_order_item_product_fitting_color( $item, $cart_item_key, $values, $order ) 
 if( isset($values['fcolor']['value']) ) 
 $key = __('Fitting color', 'woocommerce');
 $value = $values['fcolor']['value'];
 $item->update_meta_data( $key, $value );
 

And the missing field validation:

// Field validation
add_filter( 'woocommerce_add_to_cart_validation', 'dropdown_fitting_color_validation', 10, 3 );
function dropdown_fitting_color_validation( $passed, $product_id, $quantity ) 
 if( isset($_POST['fitting_color']) && empty($_POST['fitting_color']) ) 
 wc_add_notice( __( "Please select a Fitting color", "woocommerce" ), 'error' );
 return false;
 

 return $passed;