How to include a post type in the admin/backend?
Question
I'm changing the backend/admin and want to show a div above the pages. How can I include the pages like the example;
<?php
include('./tools.php') ;
this works but when I choose edit.php / edit.php?post_type=page it doesn't show anything.
Solution
First...
I'm changing the backend/admin ...
Your description makes it sound like you are hacking Core. Don't do that. It is a maintenance nightmare.
The action hook in_admin_header
looks to be placed about where you want to put your content.
190 /**
191 * Fires at the beginning of the content section in an admin page.
192 *
193 * @since 3.0.0
194 */
195 do_action( 'in_admin_header' );
Use that hook to add your content.
function admin_content_wpse_144936() {
echo 'howdy';
}
add_action('in_admin_header','admin_content_wpse_144936');
If you look at the 75 lines or so below that hook in the source you will see several other hooks that might be promising as well.
The admin_head-$hook_suffix
hook could be used to give you pretty good control over when your content is added. For example:
function admin_content_wpse_144936() {
echo 'howdy';
}
function add_admin_content_wpse_144936() {
add_action('in_admin_header','admin_content_wpse_144936');
}
add_action('admin_head-edit.php','add_admin_content_wpse_144936');