Question

What I am trying to do is pre-populate the sidebar widget area with some default widgets on theme activation.

if ( ! dynamic_sidebar( 'sidebar' ) ) :

does add the widgets but it doesnot show up in the sidebar of widgets section and

if ( is_active_sidebar( 'sidebar' ) ) {

this function doesnot work if the widgets are not loaded in the sidebar widgetized area.

I know it is possible but I am just out of idea. I googled but didnot find any solutions. Thank you for any help in advance.

Answer 1

It isn’t clear from your answer if you use the after_switch_theme hook but that the moment you need to set the widgets.

To activate the widgets I suggest writing it directly into the database with get_option('sidebars_widgets') which should give an array, and save it with update_option('sidebars_widgets', $new_activated_widgets).

This should help you get started.

/**
 * set new widgets on theme activate
 * @param string $old_theme
 * @param WP_Theme $WP_theme
 */
function set_default_theme_widgets ($old_theme, $WP_theme = null) {
    // check if the new theme is your theme
    // figure it out
    var_dump($WP_theme);

    // the name is (probably) the slug/id
    $new_active_widgets = array (
        'sidebar-name' => array (
            'widget-name-1',
            'widget-name-2',
            'widget-name-3',
        ),
        'footer-sidebar' => array(
            'widget-name-1',
            'widget-name-2',
            'widget-name-3',
        )
    );

    // save new widgets to DB
    update_option('sidebars_widgets', $new_active_widgets);
}
add_action('after_switch_theme', 'set_default_theme_widgets', 10, 2);

Tested, just paste it in functions.php of your theme.