Php无限层级并显示层级数

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今天在处理递归无限层级菜单时，遇到一个稍微烧脑的问题，如何显示当前节点所在的层级数。
废话不多说，我们先看个直观的无限层级：

技术图片
<?php
// 这里的arr是直接从数据库取出的，仅作为测试数据
$arr = array(
    array(‘id‘ => 1, ‘name‘ => ‘一级菜单a‘, ‘pid‘ => 0),// pid 父级id
    array(‘id‘ => 2, ‘name‘ => ‘一级菜单b‘, ‘pid‘ => 0),
    array(‘id‘ => 3, ‘name‘ => ‘二级菜单a‘, ‘pid‘ => 1),
    array(‘id‘ => 4, ‘name‘ => ‘二级菜单b‘, ‘pid‘ => 1),
    array(‘id‘ => 5, ‘name‘ => ‘二级菜单c‘, ‘pid‘ => 2),
    array(‘id‘ => 6, ‘name‘ => ‘二级菜单d‘, ‘pid‘ => 2),
    array(‘id‘ => 7, ‘name‘ => ‘三级菜单a‘, ‘pid‘ => 3),
    array(‘id‘ => 8, ‘name‘ => ‘三级菜单b‘, ‘pid‘ => 3),
    array(‘id‘ => 9, ‘name‘ => ‘四级菜单a‘, ‘pid‘ => 8),
);

/** 获取所有子节点
 * @param $data 所有节点数组
 * @param $id   $pid 父级节点id
 * @param $level  层级
 * @return array
 */
function getTree($data, $pid, $level = 0)

    $list = array();
    foreach ($data as $k => $v) 
        if ($v[‘pid‘] == $pid) 
            $v[‘level‘] = $level;
            $v[‘name‘] = $v[‘name‘].‘(‘.($level+1).‘级)‘; // 这里可以加个层级次数
            $v[‘children‘] = getTree($data, $v[‘id‘], $level + 1);
            if ($v[‘children‘] == null)
                unset($v[‘children‘]);
            
            $list[] = $v;
        
    
    return $list;



$menu = getTree($arr, 0, 0);

$json = json_encode($menu);
?>
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <script src="https://cdn.jsdelivr.net/npm/vue"></script>

    <style>
        *
            box-sizing: border-box;
            margin: 0;padding: 0;
        
        *:before,*:after
            box-sizing: border-box;
        
        ul,
        li 
            list-style: none;
        

        .l_tree_container 
            width: 100%;
            height: 100%;
            box-shadow: 0 0 3px #ccc;
            margin: 13px;
            position: relative;
        

        .l_tree 
            width: calc(100% - 44px);
            height: 100%;
            padding-left: 42px;
        
        .l_tree_branch 
            width: 100%;
            height: 100%;
            display: block;
            padding: 13px;
            position: relative;
        

        .l_tree_branch .l_tree_children_btn 
            width: 19px;
            height: 19px;
            background-color: #23b1f0;
            font-size: 14px;
            text-align: center;
            color: #ffffff;
            outline: none;
            border: 0;
            cursor: pointer;
        

        ul.l_tree:before 
            content: ‘‘;
            border-left: 1px dashed #999999;
            height: calc(100%);
            position: absolute;
            left: 10px;
            top: 0px;
        

        .l_tree .l_tree_branch:last-child::before 
            content: ‘‘;
            width: 3px;
            height: calc(100% - 24px);
            display: block;
            background-color: #ffffff;
            position: absolute;
            bottom: 0;
            left: -34px;
        

        .l_tree,
        .l_tree_branch 
            position: relative;
        

        .l_tree_branch::after 
            content: ‘‘;
            width: 40px;
            height: 0;
            border-bottom: 1px dashed #000;
            position: absolute;
            right: calc(100% - 9px);
            top: 22px;
        

        .l_tree_container>.l_tree::before,
        .l_tree_container>.l_tree>.l_tree_branch::after 
            display: none;
        
    </style>
</head>

<body>

<div id="demo">
    <div class="l_tree_container">
        <ew-tree :model="testdata"></ew-tree>
    </div>
</div>

<script>
    // 树组件
    Vue.component(‘ew-tree‘, 
        template: `
        <ul class="l_tree">
            <li class="l_tree_branch" v-for="item in model" :key="item.id">
                <div class="l_tree_click">
                    <button type="button" class="l_tree_children_btn" v-if="item.children"  @click="toggle(item)"> !item.show ? ‘-‘ : ‘+‘ </button>
                    <span class="l_folder"> item.name </span>
                </div>
                <ew-tree v-show="!item.show" v-if="item.children" :model="item.children"></ew-tree>
            </li>
        </ul>`,
        props: 
            model: 
        ,
        methods: 
            toggle: function (item) 
                var idx = this.model.indexOf(item)
                Vue.set(this.model[idx], ‘show‘, !item.show)
            
        
    );
    new Vue(
        el: "#demo",
        data() 
            return 
                testdata: <?php echo $json?>
            
        
    )
</script>

</body>
</html>
技术图片

技术图片

我们看到所有节点层级数没问题，那么我如何查看节点中pid=3的所有节点层级关系呢

$menu = getTree($arr, 3, 0);

技术图片

显然不对，况且菜单展示并不友好，pid=3的父节点至少要显示在顶层吧。层级数暂且不管，我们先解决如何显示顶层pid=3的树形结构：
pid=3对应的节点是：二级菜单a。这个可以直接根据数据id查询出来，此处仅做演示哈。调整下代码：

$menu = getTree($arr, 3, 0);
$menu = array([‘name‘ => ‘二级菜单a‘,‘children‘=> $menu]);
$json = json_encode($menu);

技术图片

OK，完美，同样要显示所有pid=1的节点层级关系，一样，pid=1对应的节点是 一级菜单a

$menu = getTree($arr, 1, 0);
$menu = array([‘name‘ => ‘一级菜单a‘,‘children‘=> $menu]);
$json = json_encode($menu);

技术图片

好，回到 刚才的话题，如何正确的显示每个节点所在的层级数呢？ 这里我也思考了很久，也没找到快捷的方法。
最终我还是递归的查询本节点所有的父节点id集合：完整代码如下：

技术图片
<?php
// 这里的arr是直接从数据库取出的，仅作为测试数据
$arr = array(
    array(‘id‘ => 1, ‘name‘ => ‘一级菜单a‘, ‘pid‘ => 0),// pid 父级id
    array(‘id‘ => 2, ‘name‘ => ‘一级菜单b‘, ‘pid‘ => 0),
    array(‘id‘ => 3, ‘name‘ => ‘二级菜单a‘, ‘pid‘ => 1),
    array(‘id‘ => 4, ‘name‘ => ‘二级菜单b‘, ‘pid‘ => 1),
    array(‘id‘ => 5, ‘name‘ => ‘二级菜单c‘, ‘pid‘ => 2),
    array(‘id‘ => 6, ‘name‘ => ‘二级菜单d‘, ‘pid‘ => 2),
    array(‘id‘ => 7, ‘name‘ => ‘三级菜单a‘, ‘pid‘ => 3),
    array(‘id‘ => 8, ‘name‘ => ‘三级菜单b‘, ‘pid‘ => 3),
    array(‘id‘ => 9, ‘name‘ => ‘四级菜单a‘, ‘pid‘ => 8),
);

/** 获取所有子节点
 * @param $data 所有节点数组
 * @param $id $pid 父级节点id
 * @param $level  层级
 * @return array
 */
function getTree($data, $pid, $level = 0)

    $list = array();
    foreach ($data as $k => $v) 
        if ($v[‘pid‘] == $pid) 
            $v[‘level‘] = $level;
            $v[‘name‘] = $v[‘name‘] . ‘(‘ . ($level + 1) . ‘级)‘; // 这里可以加个层级次数
            $v[‘children‘] = getTree($data, $v[‘id‘], $level + 1);
            if ($v[‘children‘] == null) 
                unset($v[‘children‘]);
            
            $list[] = $v;
        
    
    return $list;


/** 根据子节点获取父节点id
 * @param $data 所有节点数组
 * @param $id   id  主键id
 * @return array
 */
function getParentid($data, $id)

    $arr = array();
    foreach ($data as $v) 
        if ($v[‘id‘] == $id) 
            $arr[] = $v;
            //$arr[$v[‘id‘]]=$v[‘name‘];
            $arr = array_merge(getParentid($data, $v[‘pid‘]), $arr);
        
    
    return $arr;



$id = 8 ; // 对应的节点是: 三级菜单b 对应的pid 是 3
$pid = 3; // 对应的节点是  二级菜单a

$toparr = getParentid($arr, $id); // 节点为8的所有父节点 id: 1 3  8 这里包含了自身，注意剔除

$level = count($toparr); // 节点所在的层级数
$menu = getTree($arr, $pid, $level-1);
if($pid)
    $menu = array([‘name‘ => ‘二级菜单a‘ . ‘(‘ . ($level-1) . ‘级)‘, ‘children‘ => $menu]);

$json = json_encode($menu);
?>
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <script src="https://cdn.jsdelivr.net/npm/vue"></script>

    <style>
        * 
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        

        *:before, *:after 
            box-sizing: border-box;
        

        ul,
        li 
            list-style: none;
        

        .l_tree_container 
            width: 100%;
            height: 100%;
            box-shadow: 0 0 3px #ccc;
            margin: 13px;
            position: relative;
        

        .l_tree 
            width: calc(100% - 44px);
            height: 100%;
            padding-left: 42px;
        

        .l_tree_branch 
            width: 100%;
            height: 100%;
            display: block;
            padding: 13px;
            position: relative;
        

        .l_tree_branch .l_tree_children_btn 
            width: 19px;
            height: 19px;
            background-color: #23b1f0;
            font-size: 14px;
            text-align: center;
            color: #ffffff;
            outline: none;
            border: 0;
            cursor: pointer;
        

        ul.l_tree:before 
            content: ‘‘;
            border-left: 1px dashed #999999;
            height: calc(100%);
            position: absolute;
            left: 10px;
            top: 0px;
        

        .l_tree .l_tree_branch:last-child::before 
            content: ‘‘;
            width: 3px;
            height: calc(100% - 24px);
            display: block;
            background-color: #ffffff;
            position: absolute;
            bottom: 0;
            left: -34px;
        

        .l_tree,
        .l_tree_branch 
            position: relative;
        

        .l_tree_branch::after 
            content: ‘‘;
            width: 40px;
            height: 0;
            border-bottom: 1px dashed #000;
            position: absolute;
            right: calc(100% - 9px);
            top: 22px;
        

        .l_tree_container > .l_tree::before,
        .l_tree_container > .l_tree > .l_tree_branch::after 
            display: none;
        
    </style>
</head>

<body>

<div id="demo">
    <div class="l_tree_container">
        <ew-tree :model="testdata"></ew-tree>
    </div>
</div>

<script>
    // 树组件
    Vue.component(‘ew-tree‘, 
        template: `
        <ul class="l_tree">
            <li class="l_tree_branch" v-for="item in model" :key="item.id">
                <div class="l_tree_click">
                    <button type="button" class="l_tree_children_btn" v-if="item.children"  @click="toggle(item)"> !item.show ? ‘-‘ : ‘+‘ </button>
                    <span class="l_folder"> item.name </span>
                </div>
                <ew-tree v-show="!item.show" v-if="item.children" :model="item.children"></ew-tree>
            </li>
        </ul>`,
        props: 
            model: 
        ,
        methods: 
            toggle: function (item) 
                var idx = this.model.indexOf(item)
                Vue.set(this.model[idx], ‘show‘, !item.show)
            
        
    );
    new Vue(
        el: "#demo",
        data() 
            return 
                testdata: <?php echo $json?>
            
        
    )
</script>

</body>
</html>
技术图片

技术图片

同样要显示所有节点：直接把pid赋值0，比如：

技术图片
$id = 2 ; // 对应的节点是: 一级菜单b 对应的pid 是 0
$pid = 0; // 对应的节点是 0 为 一级节点  显示所有节点，上面的$id用不到

$toparr = getParentid($arr, $id); //

$level = count($toparr); // 节点所在的层级数
$menu = getTree($arr, $pid, $level-1);
if($pid)
    $menu = array([‘name‘ => ‘二级菜单a‘ . ‘(‘ . ($level-1) . ‘级)‘, ‘children‘ => $menu]);

$json = json_encode($menu);
技术图片

技术图片

 看起来没毛病，博友们如果有好的办法获取任意一个节点所处的层级数，欢迎拍砖留言哈。

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