update

app/adminapi/lists/material/MaterialClassifyLists.php

@@ -60,8 +60,8 @@ class MaterialClassifyLists extends BaseAdminDataLists implements ListsSearchInt
             ->order(['id' => 'asc'])
             ->select()
             ->toArray();
-	    $tree = buildTree($data,'pid');
-	    return $tree;
+	    $data[] = ['id'=>0,'pid'=>0,'name'=>'顶级分类'];
+	    return buildTree($data,'pid');
     }