Preset Widgets ONLY after site is initially created

Question

I want to preset some widgets using functions included in my theme ONLY after a site is initially created (my theme is the default for all new sites in my instance of WordPress).

I DO NOT want my preset widgets to replace existing widgets when a user activates my theme UNLESS their existing widget areas are different from those in my theme.

I've modelled my widgets_init function on the one found in the Thematic theme framework. Thematic adds preset widgets using the following conditional:

if ( isset( $_GET['activated'] ) )

Thus when Thematic is activated, it wipes out existing widgets and adds its own preset widgets... I want my theme to use existing widgets if they are in widget areas my theme supports (i.e. a user switches from one child theme to another, both of which use my theme as their parent)

I know there is register_activation_hook but that seems to be designed for plugin functions and not functions included in themes... Here are questions:

1. Is there an action that is run ONLY after a site has been initially created?

2. Alternatively are their conditions I can check to determine whether a site has just been created?

Answer 1

Why not output your Theme's custom Widgets using the_widget(), inside of a if ( ! dynamic_sidebar( 'sidebar-name' ) ) conditional?

e.g.

<?php if ( !dynamic_sidebar( 'sidebar-right' ) ) {

$widgetsidebarrightargs = array(
    'before_widget' => '<div class="widget">',
    'after_widget' => '</div>',
    'before_title' => '<div class="title widgettitle">',
    'after_title' => '</div>'
);

the_widget('WP_Widget_Calendar' , 'title=' , $widgetsidebarrightargs );
the_widget( 'oenology_widget_linkrollbycat' , 'title=Oenology Links by Cat' , $widgetsidebarrightargs );
the_widget('WP_Widget_Meta' , 'title=Meta' , $widgetsidebarrightargs );

} ?>

This is what I use in my Theme. The oenology_widget_linkrollbycat Widget is a custom Theme Widget. Simply replace with your own Widget names.

This way, your Widgets are applied to the specified sidebar by default, unless and until the user adds his own Widgets to the sidebar via Dashboard -> Appearance -> Widgets.