I am using the WP Plugin Boilerplate to develop a plugin, but when I activate the plugin, the require files and actions I put inside the activate() function are not working. I have tested the class and method by using die('Plugin error') and it should this message so I am not sure as to why the the other statements aren’t working. There is also no PHP error being thrown.

class Wp_Portfolio_Pro_Activator {

    /**
     * Short Description. (use period)
     *
     * Long Description.
     *
     * @since    1.0.0
     */
    public static function activate() {
        // Require Kirki and setting for plugin build on framework.
        self::load_files();

        add_action( 'admin_notices', array( __CLASS__, 'admin_notice' ) );
    }

    public static function admin_notice() {
        $message="<div class="notice notice-success"><p>";
        $message .= sprintf( __( 'Hello %s!', 'my-plugin' ), '<strong>' . get_current_user_name() . '</strong>' );
        $message .= '</p><p>';
        $message .= __( 'Thank you for downloading WP Portfolio Pro. Edit the setting from the customizer.', 'wp-portfolio-pro' );
        $message .= '</p>';
        $message .= '<a href="' . esc_url( admin_url( 'customize.php?customize_changeset_uuid=' . get_theme_mods_changeset_post_id() ) ) . '"><button>Go to settings</button></a></div>';
        echo $message;
        printf( '<div class="notice notice-success is-dismissible">%1$s</div>', $message );
    }

    public static function load_files() {
        // Require Kirki and setting for plugin build on framework.
        require_once plugin_dir_path( __FILE__ ) . 'includes/kirki/kirki.php';
        require_once plugin_dir_path( __FILE__ ) . 'includes/wp-portfolio-pro-kirki.php';
    }

}

This is the code in the main file that calls the class and runs the activate method:

/**
 * The code that runs during plugin activation.
 * This action is documented in includes/class-wp-portfolio-pro-activator.php
 */
function activate_wp_portfolio_pro() {
    require_once plugin_dir_path( __FILE__ ) . 'includes/class-wp-portfolio-pro-activator.php';
    Wp_Portfolio_Pro_Activator::activate();
}

register_activation_hook( __FILE__, 'activate_wp_portfolio_pro' );