Unlimited categories, query data from database, recursively perform custom sorting in arrays

Unlimited classification, querying data from the database, and recursively performing custom sorting in the array. I also realized that there are many shortcomings and they are not handled well. There may be a better way. Let's discuss it together. It's more than 100 lines. Not all

class Tree{
 protected $arr = array(); //Sort array
 protected $info = array(); //Storage error information
 protected $tree = array(); //Storage generated class array
 protected $flag = true; //Flag bit

 public function __construct()
 {

 }
 //Get data
 public function data($fid,$arr)
 {
 $this->checkArr($arr );
 $this->checking();
 $this->chindAll($fid);
 return $this->tree;
 }

 //Judge whether the parameters meet the requirements
 protected function checkArr($ val)
 {
 static $num = 0;
 if(is_array($val)){
 foreach($val as $Varr){
 $this->isKeyVal('id', $Varr, $num);
 $this->isKeyVal('parentid', $Varr, $num);
 $this->isKeyVal('name', $Varr, $num);
 $num++;
 }
 }
 $this- >arr = $val;
 }
 //Whether the stored id is an array
 protected function checkNum($val)
 {
 if(!is_numeric($val)){
 $this->info[] = ' The incoming parameter '.$val.' is not a numerical value';
 $this->flag = false;
 $this->checking();
 }
 }
 //Verification, output error message
 protected function checking( ){
 if(!$this->flag){
 echo '';
 var_dump($this->info);
 exit();
 }
 }

 //Judge array key Whether it exists and whether it has a value
 protected function isKeyVal($key, $arr, $num)
 {
 if(!array_key_exists($key, $arr))
 {
 $this->info[] = $num. 'Array key'.$key.'does not exist';
 $this->flag = false;

 }
 }

 //Get the son
 public function getChind($fid)
 {
 static $num = 0 ;
 $arr = array();
 $this->checkNum($fid);
 foreach($this->arr as $key=>$row){
 if( $row['parentid'] == $fid){
 $arr[] = $row;
 unset($this->arr[$key]);
 }
 }
 if(!empty($arr)){
 $num++;
 return $this->sortArr($arr);
 }else{
 return null;
 }
 }

 //Get my son and grandson
 public function chindAll($fid,$input=null)
 {
 static $ n =0;
 $n++;
 $arr = $this->getChind($fid);
 if(!empty($arr)){
 $count = count($arr);
 if(empty($ input)){
 for($i=0; $i<$count ;$i++){
 $this->tree[$i] = $arr[$i];
 }