Displays the first active widget panel (sidebar - a panel that has at least one widget). You can specify the ID or number of the panel to display if there is more than one widget panel on the site.
dynamic_sidebar() returns true or false, and with the returned result, it also displays the widget panel on the screen. The return value can be used, for example, to determine whether to process the code that replaces widgets when there are no widgets in the panel (see example #1).
If you used a number as the argument id when registering the widget panel using the function register_sidebar(), then specify that number in dynamic_sidebar(). If you used a name (string), then specify it. For more details, see below in the section Multiple sidebars.
The identifier of the panel specified in the id parameter of the register_sidebar() function when registering the panel. If a number is specified, it will look for the panel with ID sidebar-$index. Default: 1 (sidebar-1)
This example shows how to output the first non-empty sidebar (no sidebar id was specified when registering) or if it is not found, then display the specified code:
Here we check if the bar and its widgets were present. We'll check for a panel so that we don't have to display extra HTML tags (<ul id="sidebar">) if the sidebar is empty:
When registering more than one widget bar with register_sidebar(), it is more convenient to specify an id for each bar.
We can NOT specify an id, then the panel will get a serial number. But in this case, when editing the theme will be difficult to understand which panel is which, because the numbers 1, 2, 3 does not say anything. But if we specify a name, it becomes much clearer:
From the example, you can see that strings are more convenient: when you look in a theme and see dynamic_sidebar('top_menu' ) it is immediately clear that the main menu bar is called.
The id argument MUST NOT contain spaces, capital letters, or non Latin letters. It can use a dash - and underscore _. It must also be unique. By specifying the id we can also specify the name, description and translations for them:
register_sidebar( [
'id' => 'top-menu',
'name' => __( 'Top Menu', $text_domain ),
'description' => __( 'This sidebar is located above the age logo.', $text_domain ),
] );
Notes
Global. Array. $wp_registered_sidebars The registered sidebars.
Global. Array. $wp_registered_widgets The registered widgets.
function dynamic_sidebar( $index = 1 ) {
global $wp_registered_sidebars, $wp_registered_widgets;
if ( is_int( $index ) ) {
$index = "sidebar-$index";
} else {
$index = sanitize_title( $index );
foreach ( (array) $wp_registered_sidebars as $key => $value ) {
if ( sanitize_title( $value['name'] ) === $index ) {
$index = $key;
break;
}
}
}
$sidebars_widgets = wp_get_sidebars_widgets();
if ( empty( $wp_registered_sidebars[ $index ] ) || empty( $sidebars_widgets[ $index ] ) || ! is_array( $sidebars_widgets[ $index ] ) ) {
/** This action is documented in wp-includes/widget.php */
do_action( 'dynamic_sidebar_before', $index, false );
/** This action is documented in wp-includes/widget.php */
do_action( 'dynamic_sidebar_after', $index, false );
/** This filter is documented in wp-includes/widget.php */
return apply_filters( 'dynamic_sidebar_has_widgets', false, $index );
}
$sidebar = $wp_registered_sidebars[ $index ];
$sidebar['before_sidebar'] = sprintf( $sidebar['before_sidebar'], $sidebar['id'], $sidebar['class'] );
/**
* Fires before widgets are rendered in a dynamic sidebar.
*
* Note: The action also fires for empty sidebars, and on both the front end
* and back end, including the Inactive Widgets sidebar on the Widgets screen.
*
* @since 3.9.0
*
* @param int|string $index Index, name, or ID of the dynamic sidebar.
* @param bool $has_widgets Whether the sidebar is populated with widgets.
* Default true.
*/
do_action( 'dynamic_sidebar_before', $index, true );
if ( ! is_admin() && ! empty( $sidebar['before_sidebar'] ) ) {
echo $sidebar['before_sidebar'];
}
$did_one = false;
foreach ( (array) $sidebars_widgets[ $index ] as $id ) {
if ( ! isset( $wp_registered_widgets[ $id ] ) ) {
continue;
}
$params = array_merge(
array(
array_merge(
$sidebar,
array(
'widget_id' => $id,
'widget_name' => $wp_registered_widgets[ $id ]['name'],
)
),
),
(array) $wp_registered_widgets[ $id ]['params']
);
// Substitute HTML `id` and `class` attributes into `before_widget`.
$classname_ = '';
foreach ( (array) $wp_registered_widgets[ $id ]['classname'] as $cn ) {
if ( is_string( $cn ) ) {
$classname_ .= '_' . $cn;
} elseif ( is_object( $cn ) ) {
$classname_ .= '_' . get_class( $cn );
}
}
$classname_ = ltrim( $classname_, '_' );
$params[0]['before_widget'] = sprintf(
$params[0]['before_widget'],
str_replace( '\\', '_', $id ),
$classname_
);
/**
* Filters the parameters passed to a widget's display callback.
*
* Note: The filter is evaluated on both the front end and back end,
* including for the Inactive Widgets sidebar on the Widgets screen.
*
* @since 2.5.0
*
* @see register_sidebar()
*
* @param array $params {
* @type array $args {
* An array of widget display arguments.
*
* @type string $name Name of the sidebar the widget is assigned to.
* @type string $id ID of the sidebar the widget is assigned to.
* @type string $description The sidebar description.
* @type string $class CSS class applied to the sidebar container.
* @type string $before_widget HTML markup to prepend to each widget in the sidebar.
* @type string $after_widget HTML markup to append to each widget in the sidebar.
* @type string $before_title HTML markup to prepend to the widget title when displayed.
* @type string $after_title HTML markup to append to the widget title when displayed.
* @type string $widget_id ID of the widget.
* @type string $widget_name Name of the widget.
* }
* @type array $widget_args {
* An array of multi-widget arguments.
*
* @type int $number Number increment used for multiples of the same widget.
* }
* }
*/
$params = apply_filters( 'dynamic_sidebar_params', $params );
$callback = $wp_registered_widgets[ $id ]['callback'];
/**
* Fires before a widget's display callback is called.
*
* Note: The action fires on both the front end and back end, including
* for widgets in the Inactive Widgets sidebar on the Widgets screen.
*
* The action is not fired for empty sidebars.
*
* @since 3.0.0
*
* @param array $widget {
* An associative array of widget arguments.
*
* @type string $name Name of the widget.
* @type string $id Widget ID.
* @type callable $callback When the hook is fired on the front end, `$callback` is an array
* containing the widget object. Fired on the back end, `$callback`
* is 'wp_widget_control', see `$_callback`.
* @type array $params An associative array of multi-widget arguments.
* @type string $classname CSS class applied to the widget container.
* @type string $description The widget description.
* @type array $_callback When the hook is fired on the back end, `$_callback` is populated
* with an array containing the widget object, see `$callback`.
* }
*/
do_action( 'dynamic_sidebar', $wp_registered_widgets[ $id ] );
if ( is_callable( $callback ) ) {
call_user_func_array( $callback, $params );
$did_one = true;
}
}
if ( ! is_admin() && ! empty( $sidebar['after_sidebar'] ) ) {
echo $sidebar['after_sidebar'];
}
/**
* Fires after widgets are rendered in a dynamic sidebar.
*
* Note: The action also fires for empty sidebars, and on both the front end
* and back end, including the Inactive Widgets sidebar on the Widgets screen.
*
* @since 3.9.0
*
* @param int|string $index Index, name, or ID of the dynamic sidebar.
* @param bool $has_widgets Whether the sidebar is populated with widgets.
* Default true.
*/
do_action( 'dynamic_sidebar_after', $index, true );
/**
* Filters whether a sidebar has widgets.
*
* Note: The filter is also evaluated for empty sidebars, and on both the front end
* and back end, including the Inactive Widgets sidebar on the Widgets screen.
*
* @since 3.9.0
*
* @param bool $did_one Whether at least one widget was rendered in the sidebar.
* Default false.
* @param int|string $index Index, name, or ID of the dynamic sidebar.
*/
return apply_filters( 'dynamic_sidebar_has_widgets', $did_one, $index );
}
