我有以下在中实例化的类function.php 文件在构造器中，我为主题设置了激活和停用挂钩。当我真的在这个主题之间切换，比如说十四岁，然后再回来的时候，这两个词似乎都不叫了。由于不调用echo语句：

namespace Core;

class Activation {

    protected $themeOptions = null;

    public function __construct(){
        if ($this->themeOptions === null) {
            $this->themeOptions = \\Freya\\Factory\\Pattern::create(\'Freya\\Templates\\Options\');
        }

        if(is_admin()) {
            echo \'Sample\';
            // On Activation ...
            add_action(\'after_theme_switch\', array($this, \'themeActivation\'));

            // On Deactivation ...
            add_action(\'switch_theme\', array($this, \'themeDeactivation\'));
        }
    }

    public function themeActivation(){
        echo \'activated\';
        $this->setUpPluginOptions();
        $this->installPlugins();
    }

    public function themeDeactivation(){
        echo \'deactivated\';
        $this->themeOptions->deleteOptions(array (
            \'theme_options\',
            \'plugin_management\'
        ));
    }

    public function plugin_install_error_message() {
        $this->themeOptions->renderView(\'plugin_install_error_message\');
    }

    protected function installPlugins() {
        if (!get_option(\'plugin_installed\') && !get_option(\'plugin_install_error\') && is_admin()) {
            $pluginManagement = new \\Core\\Plugins\\InstallPlugins();
            $pluginManagement->installPlugins();

            if (get_option(\'plugin_install_error\')) {
                add_action(\'admin_notices\', array ($this, \'plugin_install_error_message\'));
            }
        }
    }

    protected function setUpPluginOptions() {
        $this->themeOptions->createOptions(
            array (
                \'plugin_management\' => array (
                    \'plugin_installed\',
                    \'plugin_install_error\',
                    \'plugin_install_success\',
                )
            )
        );
    }
}

有人能告诉我为什么add_action 不是在做我想做的吗？我必须打电话吗do_action? is there something I am missing?