Add Meta Box not showing on New Post - Custom meta box not showing

Question

This issue has plagued me over a couple projects. I used the default Wordpress class-based template provided in the Codex to start, and built outward. The only issue I face is that my custom meta boxes will not show when creating a new post (add post). This is usually in conjunction with custom post types, but as the code from the Wordpress demonstrates, it occurs with just a regular meta box.

What needs to be done to ensure this will display when clicking 'Add New Post'?

<?php
/*
Plugin Name: TestPlug
Description: Blank
Author: No One
Version: 1.0
*/
function call_someClass() {
 return new someClass();
}
if ( is_admin() ) add_action( 'load-post.php', 'call_someClass' );

class someClass {
    public function __construct()
    {
        add_action( 'add_meta_boxes', array( &$this, 'add_some_meta_box' ) );
    }

    public function add_some_meta_box()
    {
        add_meta_box(
             'some_meta_box_name'
            ,'Some Meta Box Headline'
            ,array( &$this, 'render_meta_box_content' )
            ,'post'
            ,'advanced'
            ,'high'
        );
    }

    public function render_meta_box_content()
    {
        echo '<h1>TEST OUTPUT - this gets rendered inside the meta box.</h1>';
    }
}
?>

Answer 1

I would create the instance of the class on init or even admin_init and not on 'load-post.php'.

Hooking into load-post.php will not add the boxes to NEW posts and only posts that are already saved. The correct hook to add meta boxes to ONLY new posts is 'load-post-new.php'.

If you want to have the meta box display on both new posts and existing posts, use the 'add_meta_boxes' hook.

Answer 2

replace

if ( is_admin() ) add_action( 'load-post.php', 'call_someClass' );

With

if ( is_admin() ) {
    add_action( 'load-post.php', 'call_someClass' );
    add_action( 'load-post-new.php', 'call_someClass'  );
}

Answer 3

Edit: I was wrong, admin_menu is not what you need. However after researching, I came up with this which is working for me:

add_action( 'admin_init', 'add_some_meta_box', 1 );

function add_some_meta_box()
{
    add_meta_box(
         'some_meta_box_name'
        ,'Some Meta Box Headline'
        ,'render_meta_box_content'
        ,'post'
        ,'normal'
        ,'high'
    );
}

function render_meta_box_content()
{
    echo '<h1>TEST OUTPUT - this gets rendered inside the meta box.</h1>';
}

It seems that taking it out of a class makes it work, not sure why though but it could possibly be a bug?

Answer 4

The problem in the top code could be that you defined the 'public function __construct()' but you never actually called it.