How to add a help tab to all admin pages - including plugin pages

Question

I have working code which adds a help tab to all screens in the admin which already have help options or a help screen - however, screens which don't have contextual help - such as the plugin I writing, also don't recognize the add_action call - how can I ensure that the help_tab appears on each and every screen in the admin?

Some simple code - but it's more or less exactly like in the Codex.

I add the action in the class __construct

// add help tab to admin UI ##
add_action( "load-{$GLOBALS['pagenow']}", array( $this, 'add_help_tab' ), 20 );

This calls a method in the class "add_help_tab":

public function add_help_tab() {
        foreach ( $this->help_tabs as $id => $data ) {
            get_current_screen()->add_help_tab( 
                array(
                    'id'       => $id
                   ,'title'    => __( $data['title'], 'q_support' )
                   // Use the content only if you want to add something
                   // static on every help tab. Example: Another title inside the tab
                   ,'callback' => array( $this, 'callback_function' )
                ) 
            );
        }
}

Which in turn calls the callback method "callback_function" - this all works as expected, except on screens without pre-existing help tabs - is there a way I can ensure each and every page includes the help tab feature?

Answer 1

This is how you can add help tabs to all admin pages—no matter if there already are any, or not:

add_action('in_admin_header', 'wpse_124979_add_help_tabs');

function wpse_124979_add_help_tabs() {
    if ($screen = get_current_screen()) {
        $help_tabs = $screen->get_help_tabs();
        $screen->remove_help_tabs();

        $screen->add_help_tab(array(
            'id' => 'my_help_tab',
            'title' => 'My Help',
            'content' => '<p>My help content...</p>',
        ));

        if (count($help_tabs))
            foreach ($help_tabs as $help_tab)
                $screen->add_help_tab($help_tab);
    }
} // function wpse_124979_add_help_tabs

In your OOP setting this should look something like the following:

// This could go in your constructor, for instance
add_action('in_admin_header', array($this, 'add_help_tabs'));

function add_help_tabs() {
    if ($screen = get_current_screen()) {
        $help_tabs = $screen->get_help_tabs();
        $screen->remove_help_tabs();

        foreach ($this->help_tabs as $id => $data)
            $screen->add_help_tab(array(
                'id' => $id,
                'title' => __($data['title'], 'q_support'),
                'callback' => array($this, 'callback_function'),
            ));

        if (count($help_tabs))
            foreach ($help_tabs as $help_tab)
                $screen->add_help_tab($help_tab);
    }
} // function add_help_tabs

in_admin_header is pretty much the last action hook before the screen meta (and so the help) is being rendered.

So, what do you get from this?

• Add help tabs to every single Admin page (core, plugin, other);
• your tabs will come before/on top of the original help tabs (if there are any);
• even if there are no help tabs at all, your tabs will be added to the screen meta.