How to Add New Fields in Dokan Product Form to Specify New and Used product, and Can Filter the Products by Used and New One

Question

I'm working on a WordPress/Dokan plugin. I am looking for a way to add a new field by two selectable options, New and Used product. Also, The visitors can filter the products in the shop page or search results page by New and Used products. I would really appreciate it if someone can help me?

I tried the following code. But when I add it to the child-theme, it disrupts the website function.

// ****adding extra field in single product page START****

// Adding extra field on New product popup/without popup form
add_action( 'dokan_new_product_after_product_tags','new_product_field',10 );

function new_product_field(){ ?>

     <div class="dokan-form-group">
              <label class="dokan-control-label" for=""><?php _e( 'Item condition', 'dokan' ); ?></label>
                <div class="dokan-form-group">
                    <select name="new_field" class="dokan-form-control">
                        <option value=""><?php _e( '', 'dokan' ) ?></option>
                        <option value="new"><?php _e( 'New', 'dokan' ) ?></option>
                        <option value="used"><?php _e( 'Used', 'dokan' ) ?></option>
                    </select>
                 </div>
        </div>

   <?php
}

/*
* Saving product field data for edit and update
*/

 add_action( 'dokan_new_product_added','save_add_product_meta', 10, 2 );
 add_action( 'dokan_product_updated', 'save_add_product_meta', 10, 2 );

function save_add_product_meta($product_id, $postdata){

    if ( ! dokan_is_user_seller( get_current_user_id() ) ) {
            return;
        }

        // if ( ! empty( $postdata['new_field'] ) ) {
        //     update_post_meta( $product_id, 'new_field', $postdata['new_field'] );
        // }
        update_post_meta( $product_id, 'new_field', $postdata['new_field'] );
}

/*
* Showing field data on product edit page
*/

add_action('dokan_product_edit_after_product_tags','show_on_edit_page',99,2);

function show_on_edit_page($post, $post_id){
$new_field         = get_post_meta( $post_id, 'new_field', true );
?>
   <div class="dokan-form-group">
       
        <label class="dokan-control-label" for=""><?php _e( 'Item condition', 'dokan' ); ?></label>
              <select name="new_field" class="dokan-form-control">
                    <option value="new" <?php echo ( "new_field" == 'new' ) ? 'selected' : 'Used' ?>><?php _e( 'New', 'dokan' ) ?></option>
                    <option value="used" <?php echo ( "new_field" == 'used' ) ? 'selected' : 'New' ?>><?php _e( 'Used', 'dokan' ) ?></option>
                </select>

     </div> <?php
    }

// showing on single product page
add_action('woocommerce_single_product_summary','show_product_code',13);

function show_product_code(){
      global $product;

        if ( empty( $product ) ) {
            return;
        }
 $new_field = get_post_meta( $product->get_id(), 'new_field', true );
 if (empty($new_field)) exit;

        if ( ! empty( $new_field ) ) {
            ?>

<span><?php echo esc_attr__( 'Item condition:', 'dokan' ); ?> <strong><?php echo esc_attr(    $new_field ); ?></strong></span>
            <?php
        }
}
// ****adding extra field in single product page END****

Answer 1

Here is updated code you should try

<?php 
// ****adding extra field in single product page START****

// Adding extra field on New product popup/without popup form
add_action('dokan_new_product_after_product_tags', 'new_product_field', 10);

function new_product_field() {
    // Security: Nonce field
    wp_nonce_field('new_product_field_nonce', 'new_product_field_nonce_name');
    ?>
    <div class="dokan-form-group">
        <label class="dokan-control-label" for="new_field"><?php _e('Item condition', 'dokan'); ?></label>
        <select name="new_field" class="dokan-form-control">
            <option value=""><?php _e('Select condition', 'dokan'); ?></option>
            <option value="new"><?php _e('New', 'dokan'); ?></option>
            <option value="used"><?php _e('Used', 'dokan'); ?></option>
        </select>
    </div>
    <?php
}

/*
* Saving product field data for edit and update
*/

add_action('dokan_new_product_added', 'save_add_product_meta', 10, 2);
add_action('dokan_product_updated', 'save_add_product_meta', 10, 2);

function save_add_product_meta($product_id, $postdata) {
    if (!isset($_POST['new_product_field_nonce_name']) || !wp_verify_nonce($_POST['new_product_field_nonce_name'], 'new_product_field_nonce')) {
        return;
    }

    if (isset($postdata['new_field']) && !empty($postdata['new_field'])) {
        update_post_meta($product_id, 'new_field', sanitize_text_field($postdata['new_field']));
    }
}


/*
* Showing field data on product edit page
*/

add_action('dokan_product_edit_after_product_tags', 'show_on_edit_page', 99, 2);

function show_on_edit_page($post, $post_id) {
    $new_field = get_post_meta($post_id, 'new_field', true);
    ?>
    <div class="dokan-form-group">
        <label class="dokan-control-label" for="new_field"><?php _e('Item condition', 'dokan'); ?></label>
        <select name="new_field" class="dokan-form-control">
            <option value="new" <?php selected($new_field, 'new'); ?>><?php _e('New', 'dokan'); ?></option>
            <option value="used" <?php selected($new_field, 'used'); ?>><?php _e('Used', 'dokan'); ?></option>
        </select>
    </div>
    <?php
}

// showing on single product page
add_action('woocommerce_single_product_summary', 'show_product_code', 13);

function show_product_code() {
    global $product;

    $new_field = get_post_meta($product->get_id(), 'new_field', true);
    if (!empty($new_field)) {
        echo '<span>' . esc_html__('Item condition:', 'dokan') . ' <strong>' . esc_html($new_field) . '</strong></span>';
    }
}

// ****adding extra field in single product page END****