Wordpress - Adding custom columns to custom post types

The hooks to create custom columns and their associated data for a custom post type are manage_{$post_type}_posts_columns and manage_{$post_type}_posts_custom_column respectively, where {$post_type} is the name of the custom post type.

This example from the documentation removes the author column and adds a taxonomy and meta data column:

// Add the custom columns to the book post type:
add_filter( 'manage_book_posts_columns', 'set_custom_edit_book_columns' );
function set_custom_edit_book_columns($columns) {
    unset( $columns['author'] );
    $columns['book_author'] = __( 'Author', 'your_text_domain' );
    $columns['publisher'] = __( 'Publisher', 'your_text_domain' );

    return $columns;
}

// Add the data to the custom columns for the book post type:
add_action( 'manage_book_posts_custom_column' , 'custom_book_column', 10, 2 );
function custom_book_column( $column, $post_id ) {
    switch ( $column ) {

        case 'book_author' :
            $terms = get_the_term_list( $post_id , 'book_author' , '' , ',' , '' );
            if ( is_string( $terms ) )
                echo $terms;
            else
                _e( 'Unable to get author(s)', 'your_text_domain' );
            break;

        case 'publisher' :
            echo get_post_meta( $post_id , 'publisher' , true ); 
            break;

    }
}

I wrote a function that combines manage_{$post_type}_posts_columns filter and manage_{$post_type}_posts_custom_column action.

function add_admin_column($column_title, $post_type, $cb){

    // Column Header
    add_filter( 'manage_' . $post_type . '_posts_columns', function($columns) use ($column_title) {
        $columns[ sanitize_title($column_title) ] = $column_title;
        return $columns;
    } );

    // Column Content
    add_action( 'manage_' . $post_type . '_posts_custom_column' , function( $column, $post_id ) use ($column_title, $cb) {

        if(sanitize_title($column_title) === $column){
            $cb($post_id);
        }

    }, 10, 2 );
}

Usage:

add_admin_column(__('EAN'), 'product', function($post_id){
    echo get_post_meta( $post_id , 'ean' , true ); 
});