Using WordPress ‘check_theme_switched()’ PHP function

The check_theme_switched() WordPress PHP function checks if the theme of a WordPress website has been changed. If a change is detected, it runs the ‘after_switch_theme’ hook on the next WordPress load.

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Usage

Let’s say you’ve changed your WordPress theme and want to execute some operations right after the theme switch. Here’s how you might use the check_theme_switched() function:

if ( is_admin() && false !== get_option( 'theme_switched' ) ) {
    check_theme_switched();
}

In this example, we’re checking if we’re in the WordPress admin area and if the ‘theme_switched’ option is set (i.e., the theme has been changed). If both conditions are met, we call the check_theme_switched() function.

Parameters

The check_theme_switched() function doesn’t take any parameters.

More Information

See WordPress Developer Resources: check_theme_switched()

This function was implemented in WordPress 3.3.0. As of the last update (September 2021), it’s not deprecated.

Examples

Display a notice after a theme switch

Suppose you want to display a notice to the admin after a theme switch. You could do this by adding a function to the ‘after_switch_theme’ action, like so:

add_action( 'after_switch_theme', 'my_theme_switch_notice' );

function my_theme_switch_notice() {
    add_action( 'admin_notices', 'my_theme_switch_admin_notice' );
}

function my_theme_switch_admin_notice() {
    echo '<div class="notice notice-success is-dismissible">';
    echo '<p>Your theme has been changed successfully!</p>';
    echo '</div>';
}

In this example, when a theme switch is detected, the my_theme_switch_notice() function will be triggered. This function adds another function, my_theme_switch_admin_notice(), to the ‘admin_notices’ action. The second function displays a notice in the WordPress admin area.

Reset a custom theme option after a theme switch

Suppose your theme has a custom option that should be reset whenever the theme is switched. Here’s how you could handle that:

add_action( 'after_switch_theme', 'reset_my_custom_option' );

function reset_my_custom_option() {
    update_option( 'my_custom_option', 'default_value' );
}

In this example, when a theme switch is detected, the reset_my_custom_option() function is triggered. This function resets the ‘my_custom_option’ value to ‘default_value’.

Please replace ‘my_custom_option’ and ‘default_value’ with your actual option name and default value.

Delete a transient after a theme switch

If you’re using transients in your theme and you want to delete a specific transient after a theme switch, you can do it like this:

add_action( 'after_switch_theme', 'delete_my_transient' );

function delete_my_transient() {
    delete_transient( 'my_transient' );
}

In this example, when a theme switch is detected, the delete_my_transient() function is triggered. This function deletes the ‘my_transient’ transient.

Please replace ‘my_transient’ with your actual transient name.