update

app/adminapi/lists/material/MaterialClassifyLists.php

@@ -60,7 +60,7 @@ class MaterialClassifyLists extends BaseAdminDataLists implements ListsSearchInt
             ->order(['id' => 'asc'])
             ->select()
             ->toArray();
-	    $data[] = ['id'=>0,'pid'=>0,'name'=>'顶级分类'];
+	    $data[] = ['id'=>0,'pid'=>-1,'name'=>'顶级分类'];
 	    return buildTree($data,'pid');
     }
 

app/common.php

@@ -307,7 +307,7 @@ function group_by($array, $key): array
 	return $result;
 }
 
-function buildTree($items, $parentField, $parentId = 0): array
+function buildTree($items, $parentField, $parentId = -1): array
 {
 	$tree = [];
 	foreach ($items as $item) {