save metabox with new values _wp_page_template

Question

I created a metabox to display the page templates and select a different one with a radiobutton selection. This is a replacement for the current page attributes metabox.

I'm missing something with the saving part. The _wp_page_template doesn't get updated. Here is what I currently have:

<?php 
// Add the Meta Box
function add_meta_box_template_picker() {
add_meta_box(
    'meta_box_template_picker', // $id
    'Template Picker', // $title
    'show_meta_box_template_picker', // $callback
    'page', // $page
    'normal', // $context
    'high'); // $priority
}
add_action('add_meta_boxes', 'add_meta_box_template_picker');

// The Callback
function show_meta_box_template_picker() {
$templates = get_page_templates(); 
foreach ( $templates as $template_name => $template_filename ) {
   if ($template_filename == 'template1.php' || 
       $template_filename == 'template2.php' || 
       $template_filename == 'template3.php' ){
        echo "<input type='radio' name='_wp_page_template' value='$template_filename' />$template_name<br />";         
   }else{
        echo '';
   }
}
}
// Save the Data
function save_custom_meta($post_id) {
global $templates, $post; // post of template
 $post_id = $post->ID;
// verify nonce
if (!wp_verify_nonce($_POST['meta_box_template_picker_nonce'], basename(__FILE__)))
    return $post_id;
// check autosave
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)
    return $post_id;
// check permissions
if ('page' == $_POST['post_type']) {
    if (!current_user_can('edit_page', $post_id))
        return $post_id;
    } elseif (!current_user_can('edit_post', $post_id)) {
        return $post_id;
}

// loop through fields and save the data
    $old = get_post_meta($post_id, '_wp_page_template', true);
    $new = $_POST['_wp_page_template'];
    if ($new && $new != $old) {
        update_post_meta($post_id, '_wp_page_template', $new);
    } elseif ('' == $new && $old) {
        delete_post_meta($post_id, '_wp_page_template', $old);
    }
} // end foreach

add_action('save_post', 'save_custom_meta');

?>

Hope somebody sees what I'm doing wrong.

Answer 1

I swear to god.....!!! Every time I ask a question here I seem to find the answer....

I missed the verification:
echo '<input type="hidden" name="meta_box_template_picker_nonce" value="'.wp_create_nonce(basename(__FILE__)).'" />';

Below is the complete code. If you think you can use this please do.

If you wish to use it but don't know how:
1. Create a seperate .php file and name it e.g. custom_template_picker.php
2. Add the complete code below and save this in the theme folder.
3. Open functions.php and add this anywhere before ?> =>
include 'custom_template_picker.php';
4. In functions.php also add the following to diable the current attributes metabox:

function my_remove_meta_boxes() {
remove_meta_box( 'pageparentdiv' , 'page' , 'normal' );
}
add_action( 'admin_menu', 'my_remove_meta_boxes' );

5. In the code on line 19,20 and 21 are template filenames that you wish to see. Change these if you wish to only see some templates.
   
6. Right now the output of the templates you get to see are radio buttons. You can change the echo on line 22 to whatever you wish the output should be.
   

7. Upload these files to the server and you should be set.

   <?php 
   // Add the Meta Box
   function add_meta_box_template_picker() {
   add_meta_box(
   'meta_box_template_picker', // $id
   'Template Picker', // $title
   'show_meta_box_template_picker', // $callback
   'page', // $page
   'normal', // $context
   'high'); // $priority
   }
   add_action('add_meta_boxes', 'add_meta_box_template_picker');
   
   // The Callback
   function show_meta_box_template_picker() {
   echo '<input type="hidden" name="meta_box_template_picker_nonce" value="'.wp_create_nonce(basename(__FILE__)).'" />';
   $templates = get_page_templates(); 
   foreach ( $templates as $template_name => $template_filename ) {
   if ($template_filename == 'template1.php' || 
      $template_filename == 'template2.php' || 
      $template_filename == 'template3.php' ){
       echo "<input type='radio' name='_wp_page_template' value='$template_filename' />$template_name<br />";         
   }else{
       echo '';
   }
   }
   echo get_post_meta(249, '_wp_page_template', true);
   }
   // Save the Data
   function save_custom_meta($post_id) {
   global $templates, $post; // post of template
   $post_id = $post->ID;
   // verify nonce
   if (!wp_verify_nonce($_POST['meta_box_template_picker_nonce'], basename(__FILE__)))
   return $post_id;
   // check autosave
   if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)
   return $post_id;
    // check permissions
   if ('page' == $_POST['post_type']) {
   if (!current_user_can('edit_page', $post_id))
       return $post_id;
   } elseif (!current_user_can('edit_post', $post_id)) {
       return $post_id;
   }
   
   // loop through fields and save the data
   $old = get_post_meta($post_id, '_wp_page_template', true);
   $new = $_POST['_wp_page_template'];
   if ($new && $new != $old) {
       update_post_meta($post_id, '_wp_page_template', $new);
   } elseif ('' == $new && $old) {
       delete_post_meta($post_id, '_wp_page_template', $old);
   }
   } // end foreach
   
   add_action('save_post', 'save_custom_meta');
   
   ?>
   

************Any suggestions/improvements are welcome***************

I hope I can help someone with this