How can I add the custom taxonomy categories to the posts and pages?

Question

I'm trying to build new wordpress plugin. Additional to the default wordpress categories box in the publishing screen of posts and pages, I want to add another box for custom taxonomy categories , How can I do that ?

Answer 1

All what you need to do is just pass required post types as array in the second parameter for register_taxonomy function call:

add_action( 'init', 'wpse8170_init' );
function wpse8170_init() {
    register_taxonomy( 'my-taxonomy', array( 'post' ), array(
        ...
    ) );

    // or call this function if your taxonomy is already registered
    register_taxonomy_for_object_type( 'my-taxonomy', 'page' );
}