无限极分类经常会用到，以下是一个案例，供大家参考：
知识点：
1、递归
2、PHP str_repeat(string,repeat) 函数把字符串重复指定的次数。
3、PHP unlink() 函数 unlink() 函数删除文件。
4、PHP file_exists() 函数 file_exists() 函数检查文件或目录是否存在。
扩展类：Catetree.php
<?php
namespace catetree;
class Catetree{
public function catetree($cateRes){
return $this->sort($cateRes);
}
public function sort($cateRes,$pid=0,$level=0){
static $arr=array();
foreach ($cateRes as $k => $v) {
if($v['pid']==$pid){
$v['level']=$level;
$arr[]=$v;
$this->sort($cateRes,$v['id'],$level+1);
}
}
return $arr;
}
// 处理栏目排序
public function cateSort($data,$obj){
foreach ($data as $k => $v) {
$obj->update(['id'=>$k,'sort'=>$v]);
}
}
//获取子栏目id
public function childrenids($cateid,$obj){
$data=$obj->field('id,pid')->select();
return $this->_childrenids($data,$cateid);
}
private function _childrenids($data,$cateid){
static $arr=array();
foreach ($data as $k => $v) {
if($v['pid']==$cateid){
$arr[]=$v['id'];
$this->_childrenids($data,$v['id']);
}
}
return $arr;
}
//处理批量删除
public function pdel($cateids){
foreach ($cateids as $k => $v) {
$childrenidsarr[]=$this->childrenids($v);
$childrenidsarr[]=(int)$v;
}
$_childrenidsarr=array();
foreach ($childrenidsarr as $k => $v) {
if(is_array($v)){
foreach ($v as $k1 => $v1) {
$_childrenidsarr[]=$v1;
}
}else{
$_childrenidsarr[]=$v;
}
}
$_childrenidsarr=array_unique($_childrenidsarr);
$this::destroy($_childrenidsarr);
}
}调用说明：在extend目录下新建一个目录 catetree 目录，再新建文件 Catetree.php
控制器里：
<?php
namespace app\admin\controller;
use think\Controller;
use catetree\Catetree; //引入扩展类
class Cate extends controller
{
public function lst()
{
$cate=new Catetree();
$cateObj=db('cate');
$cateRes= $cateObj->order('sort desc')->select();
$cateRes = $cate->catetree($cateRes);
$this->assign('cateRes',$cateRes);
return view();
}
public function add()
{
$cate=new Catetree();
$cateObj=db('cate');
if(request()->isPost()){
$data=input('post.');
$cateId=$cateObj->field('pid')->find($data['pid']);
$add=$cateObj->insert($data);
if($add){
$this->success('操作成功!','lst');
}else{
$this->error('操作失败!');
}
return;
}
$cateRes= $cateObj->order('sort desc')->select();
$cateRes = $cate->catetree($cateRes);
$this->assign('cateRes',$cateRes);
return view();
}
//删除(实现删除顶级分类，删除所有子类文章)
public function del($id)
{
$cate=db('cate');
$cateTree = new Catetree();
$sonids=$cateTree->childrenids($id,$cate);
$sonids[]=intval($id);
$article=db('article');
foreach ($sonids as $k => $v) {
$artRes=$article->field('id,thumb')->where(array('cate_id'=>$v))->select();
foreach ($artRes as $k1 => $v1) {
$thumbSrc=IMG_UPLAODS.$v1['thumb'];
if(file_exists($thumbSrc)){//判断文件是否存在
@unlink($thumbSrc);
}
$article->delete($v1['id']);
}
}
$del=$cate->delete($sonids);
if($del){
$this->success('操作成功!','lst');
}else{
$this->error('操作失败!');
}
}
}视图模板：
呈现层级效果：str_repeat(string,repeat) 函数把字符串重复指定的次数。
<td><?php echo str_repeat('-', $cate['level']*8) ?>{$cate.cate_name}</td>