php树形类

原本写过一个树形类，通过字符串生成，之后发现不是很好用，或者说跟模板引擎不切合，不够灵活。

现在重写一遍，希望对看到这篇文章的朋友有所帮助 --by longDD

<?php 
// +---------------------------------------------------------------------------------------------------
// | Before finding the right people, the only need to do is to make yourself good enough. 
// +---------------------------------------------------------------------------------------------------
// | Author: LongDD <741886920@qq.com> 2013.7.7
// +---------------------------------------------------------------------------------------------------
// | Description: 树形类
// +---------------------------------------------------------------------------------------------------
// 

    class Tree{
        //传入数组
        public $arr = array();
        //树形结构符号
        public $icon = array();
        //多维数组
        public $list = array();
        //tree  二维数组
        public $tree = array();
        //nav 面包屑
        public $nav = array();
        //$id字段
        public $id = '';
        //$pid字段
        public $pid = '';
        //根id
        public $root = 0;
        //子类索引
        public $index_child = 'child';
        //树形图标
        public $icons = array('body'=>'|','branch'=>'├','end'=>'└');
        //前缀
        public $prefix = 'prefix';
        //构造
        public function __construct($arr = null,$root = 0,$id = 'id',$pid = 'pid'){
            if(empty($arr)){
                return false;
                exit;
            }

            $this->id = $id;
            $this->pid = $pid;
            $this->root = $root;
            $this->arr = $arr;

        }

        //获取父类 （追溯） ps：面包屑
        public function get_nav($id = null){
            if(empty($id)){
                exit('ID必须');
            }
            $this->create_nav($id);
            return $this->nav;
        }

        //创建面包屑
        public function create_nav($id){
            foreach ($this->arr as $v) {
                if($v[$this->id] == $id){
                    $this->nav[] = $v;
                    $this->create_nav($v['pid']);
                }
            }
        }


        //获取子类（一层）
        public function get_child($pid = null){
            $pid = empty($pid)?$this->root:$pid;
            $rst = array();

            foreach ($this->arr as $k => $v) {
                if($v[$this->pid] == $pid){
                    $rst[] = $v;
                }
            }

            return $rst;
        }


        //获取数组 （多层嵌套）
        public function get_list($pid = null){
            $pid = empty($pid)?$this->root:$pid;

            $this->transition_arrary();

            //如果元素有父ID大于0,则放入父元素中（引用本身）
            foreach ($this->arr as $k => $v) {
                if($v[$this->pid] > 0){
                    $this->arr[$v[$this->pid]][$this->index_child][$v[$this->id]] = &$this->arr[$v[$this->id]];
                }
            }

            //根据根ID取有用数组
            foreach($this->arr as $v){
                if($v[$this->pid] == $pid){
                    $this->list[$v[$this->id]] = $v;
                }
            }

            return $this->list;
        }

        //转换数组
        public function transition_arrary(){
            $arr = array();
            foreach($this->arr as $v){
                $arr[$v[$this->id]] = $v;
            }
            $this->arr = $arr;
        }
        
        //获取树形数组
        public function get_tree($pid = null){
            $pid = empty($pid)?$this->root:$pid;
            $this->create_tree($pid);
            return $this->tree;
        }

        //创建树形
        public function create_tree($pid,$level=0){
            //根据父节点找寻子节点
            $arr = array();
            $arr = $this->get_child($pid);
            if(is_array($arr)){
                //判断子节点前缀
                $count = count($arr);
                // array('body'=>'|','branch'=>'├','end'=>'└');

                for($i = 0;$i<$count;$i++){
                    if($i == $count-1){
                        $arr[$i][$this->prefix] = $count>0?str_repeat($this->icons['body']."&nbsp;", $level).$this->icons['end']:$this->icons['end'];
                    }else{
                        $arr[$i][$this->prefix] = $count>0?str_repeat($this->icons['body']."&nbsp;", $level).$this->icons['branch']:$this->icons['branch'];
                    }
                    $this->tree[] = $arr[$i];
                    //递归
                    $this->create_tree($arr[$i]['id'],$level+1);
                }
            }
        }

    }
// +---------------------------------------------------------------------------------------------------
// |End of file Tree.php
// |Location: ./Tree.php
// +---------------------------------------------------------------------------------------------------

//测试
$arr  = array(
                    0 => array(
                        'id' => '1',
                        'pid' => '0',
                        'name' => 'levelOne-1',
                        ),
                    1 => array(
                        'id' => '2',
                        'pid' => '0',
                        'name' => 'levelOne-2',
                        ),
                    2 => array(
                        'id' => '3',
                        'pid' => '1',
                        'name' => 'levelTwo-1',
                        ),
                    3 => array(
                        'id' => '4',
                        'pid' => '1',
                        'name' => 'levelTwo-2',
                        ),
                    4 => array(
                        'id' => '5',
                        'pid' => '4',
                        'name' => 'levelThree-1',
                        ),
                    5 => array(
                        'id' => '6',
                        'pid' => '3',
                        'name' => 'levelThree-2',),
                    6 => array(
                        'id' => '7',
                        'pid' => '3',
                        'name' => 'levelThree-3',),
                    7 => array(
                        'id' => '8',
                        'pid' => '3',
                        'name' => 'levelThree-4',),
                    8 => array(
                        'id' => '9',
                        'pid' => '4',
                        'name' => 'levelThree-4',),
                    9 => array(
                        'id' => '10',
                        'pid' => '4',
                        'name' => 'levelThree-4',),
                );

$tree = new Tree($arr);
echo '<pre>';

// $list = $tree->get_tree();
// echo '<ul>';
// foreach($list as $v){
//     echo '<li>';
//     echo $v['prefix'].$v['name'];
//     echo '</li>';
// }
// echo '</ul>';

print_r($tree->get_nav(10));