update demo;

Author: sasou2008

demo/application/Controllers/Index.php

@@ -33,8 +33,11 @@ public function doc($params)
         $this->view->js = ['mdediter/md.min'];
         $this->view->help = \Services\Doc\Mark::getInstance()->listAll(1);
         $this->view->doc = \Services\Doc\Mark::getInstance()->listAll(2);
-        $this->view->mark = \Services\Doc\Mark::getInstance()->row($id);
-        $this->view->text = $parsedown->text($this->view->mark['app_description']);
+        $mark = \Services\Doc\Mark::getInstance()->row($id);
+        if ($mark) {
+            $this->view->mark = $mark;
+            $this->view->text = $parsedown->text($this->view->mark['app_description']);
+        }
         $this->view->display('index/doc', 'common');
     }