php - How to go about modifying the Wordpress "Pages Add New Screen"

Question

I have been thinking about developing my own theme framework for worpdress. I'd like to use jquery ui to build a bootstrap 3.0 drag and drop interface, which I already have worked out, but I can't figure out how to edit the "Pages Add New Screen" as referenced here: https://codex.wordpress.org/Pages_Add_New_Screen

Would I add files to my client side theme that affected my admin structure as well? Does anyone have any suggestions as to how to do something like this. Alot of themes these days come with these drag and drop frameworks and it would be nice, to be able to create one of my own, just need some direction on where to start editing / looking.

Answer 1

We add a Custom Meta Box and do our thing inside it.

There are some hooks that are not Meta Boxes and we can use to insert content into that admin page:

add_action( 'edit_form_top', function( $post ) 
{
    echo '<h1 style="color:red">edit_form_top</h1>';
});

add_action( 'edit_form_after_title', function( $post ) 
{
    echo '<h1 style="color:red">edit_form_after_title</h1>';
});

add_action( 'edit_form_after_editor', function( $post ) 
{
    echo '<h1 style="color:red">edit_form_after_editor</h1>';
});

add_action( 'edit_page_form', function( $post ) 
{
    // edit_page_form is ONLY for pages, the other is for the rest of post types
    echo '<h1 style="color:red">edit_page_form/edit_form_advanced</h1>';
});

add_action( 'dbx_post_sidebar', function( $post ) 
{
    echo '<h1 style="color:red">dbx_post_sidebar</h1>';
});

The widget_text block belongs to Advanced Custom Fields (it's a repeatable/sortable field). I'm not sure anymore, but I think it removes the Meta Box borders with CSS or jQuery.