Check if ACF is Active Before Using Its Functions

Safely call ACF functions without fatal errors when the plugin is deactivated.

Check for the ACF class before calling any ACF functions:

<?php
if ( class_exists( 'ACF' ) ) {
    $value = get_field( 'hero_title' );
    echo esc_html( $value );
}

Or check for a specific function:

<?php
if ( function_exists( 'get_field' ) ) {
    $value = get_field( 'hero_title' );
    echo esc_html( $value );
}

In a theme’s functions.php, wrap all ACF-dependent code:

<?php
add_action( 'acf/init', function () {
    // This only runs when ACF is active.
    acf_add_options_page( [
        'page_title' => 'Theme Settings',
        'menu_slug'  => 'theme-settings',
    ] );
} );

For plugins that depend on ACF, add a dependency check on activation:

<?php
add_action( 'admin_notices', function () {
    if ( class_exists( 'ACF' ) ) {
        return;
    }

    echo '<div class="notice notice-error"><p>';
    echo '<strong>My Plugin</strong> requires <a href="https://www.advancedcustomfields.com/" target="_blank">Advanced Custom Fields</a> to be installed and active.';
    echo '</p></div>';
} );

Using class_exists( 'ACF' ) is preferred over function_exists( 'get_field' ) because it checks for ACF specifically, not just any plugin that might define a get_field() function.