Editable Custom fields

Hi There WP lovers,

I am very new to WordPress, dabbled in PHP on and off for a couple of years… so please bare with me. This is also my first post on wp.org ever.

So here it goes…

I have recently taken over a website, that is built in WordPress. It is quite a complicated site. Apart from adding to the website, I’m also trying to fix it (Not that its broken) by illuminating most of the plugins and re-writing the functionality into the theme.

I have managed to do most of it myself. But one of the plugins that is used, is the Post Type Re-order plugin. it does exactly what I need it to do, but for a ‘business directory’ type website, to instruct users to go to a separate page just to rearrange there posts, which are ‘Paintings'(A custom post type) in this case.

I have managed to create the custom meta, display, edit(via post.php) and orderby the custom meta_value on the frontend.

What I would like to do is have a input field within the custom column.

Here is a screenshot of what I currently have:
HERE

Then when I have sorted out the inline-editing/saving, I would like to have a function that checks against the other “re-order” values and adjusts them based on the row that was changed, to avoid duplicate values.

Here is the code I currently have, you will see my attempt at using ajax-saving (Which also doesn’t work):

<?php<br />
//EDIT meta box added to post edit screen<br />
add_action("admin_init", "admin_init");<br />
function admin_init(){<br />
    $screens = array( 'painting', 'page' );<br />
    foreach ($screens as $screen) {<br />
        add_meta_box(<br />
            'painting_ro_sectionid',<br />
            __( 'Number', 'painting_ro_textdomain' ),<br />
            'painting_ro_inner_custom_box',<br />
            $screen<br />
        );<br />
    }<br />
}</p>
<p>//ADD and replace columns in edit.php for custom post types<br />
add_filter('manage_edit-painting_columns', 'add_new_painting_columns');<br />
function add_new_painting_columns($painting_columns) {<br />
    $new_columns['cb'] = '<input type="checkbox" />';<br />
	$new_columns['title'] = _x('Painting Name', 'column name');<br />
	$new_columns['number'] = __('Number', 'column name');<br />
    $new_columns['images'] = __('Images');<br />
    $new_columns['author'] = __('Author');<br />
    $new_columns['date'] = _x('Date', 'column name');<br />
    return $new_columns;<br />
}</p>
<p>add_action('manage_painting_posts_custom_column', 'manage_painting_columns', 10, 2);<br />
function manage_painting_columns($column_name, $id) {<br />
    global $wpdb;<br />
    switch ($column_name) {<br />
		case "number":<br />
			$custom = get_post_custom($post->ID);<br />
			$painting_ro = $custom['_painting_ro_my_meta_value_key'][0];<br />
			?><br />
            <script type="text/javascript"><br />
			var j = jQuery.noConflict();<br />
			j('submit').click(function() {<br />
				var formValues = j("#update_ro").serialize();<br />
				var data = { type: 'save', action: 'painting_ro_save_postdata_ajax', data: formValues }<br />
				j.post( ajaxurl, data, function(message){<br />
					alert('Saved');<br />
				});<br />
				return false;<br />
			});<br />
			</script><br />
              	<form id="update_ro"><br />
                <label>Change Order:</label><br />
			    <input type="text" name="painting_ro_new_field" value="<?php echo $painting_ro; ?>"><br />
       			 <?php submit_button(); ?><br />
                </form><br />
			<?php<br />
			break;<br />
		case 'images':<br />
			$num_images = $wpdb->get_var($wpdb->prepare("SELECT COUNT(*) FROM $wpdb->posts WHERE post_parent = {$id};"));<br />
			echo $num_images;<br />
        	break;<br />
    	default:<br />
        break;<br />
    }<br />
}</p>
<p>add_action( 'save_post', 'painting_ro_save_postdata' );<br />
add_action('wp_ajax_save_product', 'painting_ro_save_postdata_ajax');</p>
<p>function painting_ro_inner_custom_box( $post ) {<br />
  wp_nonce_field( plugin_basename( __FILE__ ), 'painting_ro_noncename' );<br />
  $value = get_post_meta( $post->ID, $key = '_painting_ro_my_meta_value_key', $single = true );<br />
  echo '<label for="painting_ro_new_field">';<br />
       _e("Add a reorder number", 'painting_ro_textdomain' );<br />
  echo '</label> ';<br />
  echo '<input type="text" id="painting_ro_new_field" name="painting_ro_new_field" value="'.($value).'" size="25" />';<br />
}</p>
<p>function painting_ro_save_postdata_ajax( $post_id ) {<br />
  global $wpdb;</p>
<p>  $post_ID = $_POST['post_ID'];<br />
  $mydata = sanitize_text_field( $_POST['painting_ro_new_field'] );</p>
<p>  add_post_meta($post_ID, '_painting_ro_my_meta_value_key', $mydata, true) or<br />
  update_post_meta($post_ID, '_painting_ro_my_meta_value_key', $mydata);</p>
<p>  update_post_meta($post->ID, "_painting_ro_my_meta_value_key", $_POST["_painting_ro_my_meta_value_key"]);<br />
  echo 'Meta Updated';<br />
  die();<br />
}</p>
<p>function painting_ro_save_postdata( $post_id ) {<br />
  global $wpdb;<br />
  $post_ID = $_POST['post_ID'];<br />
  $mydata = sanitize_text_field( $_POST['painting_ro_new_field'] );</p>
<p>  add_post_meta($post_ID, '_painting_ro_my_meta_value_key', $mydata, true) or<br />
  update_post_meta($post_ID, '_painting_ro_my_meta_value_key', $mydata);</p>
<p>  update_post_meta($post->ID, "_painting_ro_my_meta_value_key", $_POST["_painting_ro_my_meta_value_key"]);<br />
}</p>
<p>?>

I am such a noob to WP, that I’m not even sure if what i am asking is possible.

If anyone can point me in the right direction to achieve what i’m asking, that would be great ??

Thanks in advance