您必须使用如下“process\\u bulk\\u action”功能：

public function process_bulk_action() {

   //nonce validations,etc

    $action = $this->current_action();

    switch ( $action ) {

        case \'export_action\':

            // Do whatever you want
            wp_redirect( esc_url( add_query_arg() ) );
            break;

        default:
             // do nothing or something else
            return;
            break;
        }

        return;

    }
}

   public function process_bulk_action() {

        if ( isset( $_POST[\'_wpnonce\'] ) && ! empty( $_POST[\'_wpnonce\'] ) ) {
            echo \'<pre>\';
            print_r($_POST);
            echo \'</pre>\';

            $nonce  = filter_input( INPUT_POST, \'_wpnonce\', FILTER_SANITIZE_STRING );
            $action = \'bulk-\' . $this->_args[\'plural\'];

            if ( ! wp_verify_nonce( $nonce, $action ) )
                wp_die( \'Nope! Security check failed!\' );

        }

        $action = $this->current_action();

        switch ( $action ) {

            case \'delete\':
                self::delete_activity( absint( $_GET[\'activity\'] ) );

                wp_redirect( esc_url( add_query_arg() ) );

                break;

            case \'bulk-delete\':
                $ids = esc_sql( $_POST[\'bulk-selected\'] );
                foreach ( $ids as $id ) {
                    self::delete_activity( $id );
                }

                wp_redirect( esc_url( add_query_arg() ) );

                break;

            case \'bulk-export\':
                $ids = esc_sql( $_POST[\'bulk-selected\'] );

                self::export_activities( $ids );

                wp_redirect( esc_url( add_query_arg() ) );
                break;

            default:
                // do nothing or something else
                return;
                break;
        }

        return;

    }