一、前言
简单的描述一下，实习几个原理，思想，其实写很多东西，思想算是最重要的。
1、目标：将写一个无限节点的树形目录结构，如下图
步骤：
1、你的下载 插件 ztree。然后布置在你的项目中。
<ol class="dp-c"><li class="alt"><span><span><script src=</span><span class="string">"__PUBLIC__/js/jquery-1.4.4.min.js"</span><span>></script> </span></span></li><li><span><script src=<span class="string">"__PUBLIC__/js/jquery.ztree.core-3.5.js"</span><span>></script> </span></span></li></ol>
2、相关CSS
<ol class="dp-css"><li class="alt"><span><span><link rel=</span><span class="string">"stylesheet"</span><span> href=</span><span class="string">"__PUBLIC__/css/zTreeStyle/zTreeStyle.css"</span><span> type=</span><span class="string">"text/css"</span><span>> </span></span></li><li><span><link rel=<span class="string">"stylesheet"</span><span> href=</span><span class="string">"__PUBLIC__/css/zTree.css"</span><span> type=</span><span class="string">"text/css"</span><span>> </span></span></li></ol>
以上CSS 和JS 以你自己的为准。
3、目录结构DIV
<ol class="dp-css"><li class="alt"><span><span><div class=</span><span class="string">"content_wrap"</span><span> style=</span><span class="string">"background:#666;"</span><span>> </span></span></li><li><span> <div class=<span class="string">"zTreeDemoBackground left"</span><span>> </span></span></li><li class="alt"><span> <ul id=<span class="string">"treeDemo"</span><span> class=</span><span class="string">"ztree"</span><span>></ul> </span></span></li><li><span> </div> </span></li><li class="alt"><span></div> </span></li><li><span><div class=<span class="string">"content-text"</span><span> id=</span><span class="string">"text"</span><span>></div> </span></span></li></ol>
4，自己单独js中的代码
<ol class="dp-c"><li class="alt"><span><span><SCRIPT src=</span><span class="string">"__PUBLIC__/js/ztreeonload.js"</span><span>></SCRIPT> </span></span></li></ol>
里面写的相关功能 及配置！
<ol class="dp-c"><li class="alt"><span><span class="comment">//配置项</span><span> </span></span></li><li><span><span class="keyword">var</span><span> setting = { </span></span></li><li class="alt"><span> isSimpleData : true, <span class="comment">//数据是否采用简单 Array 格式，默认false 性 </span><span> </span></span></li><li><span> showLine : true, <span class="comment">//是否显示节点间的连线 </span><span> </span></span></li><li class="alt"><span> checkable : true, </span></li><li><span> callback: { </span></li><li class="alt"><span> onClick: zTreeOnClick </span></li><li><span> } </span></li><li class="alt"><span> }; </span></li><li><span> </span></li><li class="alt"><span> <span class="keyword">var</span><span> zNodes;</span><span class="comment">//数据变量</span><span> </span></span></li><li><span> </span></li><li class="alt"><span> <span class="comment">//ajax提交数据，请求后台PHP处理返回出目录结构json数据</span><span> </span></span></li><li><span> $.ajax({ </span></li><li class="alt"><span> url:<span class="string">"/admin.php/Ztree"</span><span>, </span></span></li><li><span> type: <span class="string">"get"</span><span>, </span></span></li><li class="alt"><span> async: false, </span></li><li><span> dataType:<span class="string">"json"</span><span>, </span></span></li><li class="alt"><span> success: <span class="keyword">function</span><span> (data) { </span></span></li><li><span> <span class="comment">//alert(data);</span><span> </span></span></li><li class="alt"><span> zNodes=data; <span class="comment">//将请求返回的数据存起来</span><span> </span></span></li><li><span> <span class="comment">//alert(zNodes);</span><span> </span></span></li><li class="alt"><span> }, </span></li><li><span> error: <span class="keyword">function</span><span> (){</span><span class="comment">//请求失败处理函数 </span><span> </span></span></li><li class="alt"><span> alert(<span class="string">'请求失败'</span><span>); </span></span></li><li><span> }, </span></li><li class="alt"><span> }) </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">//初始化ztree目录结构视图！</span><span> </span></span></li><li><span> $(document).ready(<span class="keyword">function</span><span>(){ </span></span></li><li class="alt"><span> <span class="comment">//alert("111");</span><span> </span></span></li><li><span> $.fn.zTree.init($(<span class="string">"#treeDemo"</span><span>), setting, zNodes); </span></span></li><li class="alt"><span> }); </span></li></ol>5、后台PHP 递归算法，从数据库中查找目录结构并且生成 JSON数据
地址：如4中，AJAX所请求的 /admin.php/Ztree】我这里是用的ThinkPHP框架，所以url是这个样子，以你自己的接口文件为准！
<ol class="dp-c"><li class="alt"><span><span><?php </span></span></li><li><span> <span class="comment">//父节点数组</span><span> </span></span></li><li class="alt"><span> <span class="vars">$arr</span><span>=</span><span class="keyword">array</span><span>(); </span></span></li><li><span> <span class="vars">$arr_str0</span><span> = </span><span class="keyword">array</span><span>(</span><span class="string">"name"</span><span> =></span><span class="string">'函数库查询'</span><span>,</span><span class="string">'children'</span><span>=></span><span class="vars">$this</span><span>->SelectSon(1)); </span><span class="comment">//父节点 Pid=1;</span><span> </span></span></li><li class="alt"><span> <span class="vars">$arr_str1</span><span> = </span><span class="keyword">array</span><span>(</span><span class="string">"name"</span><span> =></span><span class="string">'数据库查询'</span><span>,</span><span class="string">'children'</span><span>=></span><span class="vars">$this</span><span>->SelectSon(2)); </span><span class="comment">//父节点 Pid=2;</span><span> </span></span></li><li><span> </span></li><li class="alt"><span> <span class="func">array_push</span><span>(</span><span class="vars">$arr</span><span>, </span><span class="vars">$arr_str0</span><span>); </span></span></li><li><span> <span class="func">array_push</span><span>(</span><span class="vars">$arr</span><span>, </span><span class="vars">$arr_str1</span><span>);</span><span class="comment">//这里是2个父节点。</span><span> </span></span></li><li class="alt"><span> </span></li><li><span> <span class="func">echo</span><span>(json_encode(</span><span class="vars">$arr</span><span>)); </span><span class="comment">//这是最后返回给页面，也就是返回给AJAX请求后所得的返回数据 JSON数据</span><span> </span></span></li><li class="alt"><span>？> </span></li><li><span> </span></li><li class="alt"><span><span class="comment">//这里仅仅是一个方法，一个调用SelectSon()方法，返回一个数组集合！但其中用的是递归！</span><span> </span></span></li><li><span><?php </span></li><li class="alt"><span> <span class="comment">//查找子节点 Pid=父节点ID</span><span> </span></span></li><li><span> <span class="keyword">private</span><span> </span><span class="keyword">function</span><span> SelectSon(</span><span class="vars">$Pid</span><span>){ </span></span></li><li class="alt"><span> </span></li><li><span> <span class="vars">$m</span><span>=M(</span><span class="string">'ztree'</span><span>); </span></span></li><li class="alt"><span> </span></li><li><span> <span class="keyword">if</span><span>((</span><span class="vars">$info</span><span>=</span><span class="vars">$m</span><span>->where(</span><span class="string">"Pid='$Pid'"</span><span>)->select())) </span><span class="comment">//查找该父ID下的子ID</span><span> </span></span></li><li class="alt"><span> { </span></li><li><span> <span class="vars">$data</span><span>=</span><span class="keyword">array</span><span>(); </span></span></li><li class="alt"><span> <span class="keyword">for</span><span> (</span><span class="vars">$i</span><span>=0; </span><span class="vars">$i</span><span> < </span><span class="func">count</span><span>(</span><span class="vars">$info</span><span>) ; </span><span class="vars">$i</span><span>++) </span></span></li><li><span> { </span></li><li class="alt"><span> <span class="vars">$da</span><span>=</span><span class="keyword">array</span><span>(</span><span class="string">"name"</span><span> =></span><span class="vars">$info</span><span>[</span><span class="vars">$i</span><span>][</span><span class="string">'name'</span><span>],</span><span class="string">'children'</span><span>=></span><span class="vars">$this</span><span>->SelectSon(</span><span class="vars">$info</span><span>[</span><span class="vars">$i</span><span>][</span><span class="string">'id'</span><span>])); </span><span class="comment">//递归算法！</span><span> </span></span></li><li><span> </span></li><li class="alt"><span> <span class="func">array_push</span><span>(</span><span class="vars">$data</span><span>, </span><span class="vars">$da</span><span>);</span><span class="comment">//加入子节点数组</span><span> </span></span></li><li><span> }; </span></li><li class="alt"><span> </span></li><li><span> <span class="keyword">return</span><span> </span><span class="vars">$data</span><span>;</span><span class="comment">//一次性返回子节点数组，他们成为同级子节点。</span><span> </span></span></li><li class="alt"><span> } </span></li><li><span> <span class="keyword">else</span><span> </span></span></li><li class="alt"><span> { </span></li><li><span> <span class="keyword">return</span><span> null; </span></span></li><li class="alt"><span> } </span></li><li><span> </span></li><li class="alt"><span> } </span></li><li><span>?> </span></li></ol>注意：由于我是用的thinkphp框架。所以在方法调用上 有些不同，纯PHP文件中，思路应该是一样的，
首先是： 写一个数组。一个父节点的数组。
其次： 写一个方法，传递的参数是 父节点的ID，查询其子节点，在子节点中查询之后，用递归的方式继续查找子节点的子节点，直到最后查询完毕之后，返回数组给调用方法的父节点数组。然后再
<ol class="dp-c"><li class="alt"><span><span class="func">echo</span><span>(json_encode(</span><span class="vars">$arr</span><span>)); </span></span></li></ol>
转码成 JSON 将其输出，以便于AJAX异步访问，得到JSON数据。
得到之后，回到刚刚的JS功能代码中，直接初始化树目录结构，将其JSON数据传入OK。
总结：
其主要思想分2步走。第一步，是如何能把目录生成出来。先测试时，可以用静态数据。类似于
<ol class="dp-c"><li class="alt"><span><span class="keyword">var</span><span> node=[ </span></span></li><li><span> {name:<span class="string">'父节点'</span><span>,children:[{name:</span><span class="string">'子节点'</span><span>,children:null},{name:</span><span class="string">'同级子节点'</span><span>,children:null}]} </span></span></li><li class="alt"><span>] </span></li><li><span> </span></li><li class="alt"><span>先分析一下，这串数据，他有什么规律。你就会发现。其实很有规律。无限节点，其实就是每个json中，有children，而且 </span></li><li><span>还有同级子节点。 </span></li></ol>你先用固定数据 生成目录结构之后
你就可以开始考虑，动态的向node传目录结构的数据了。就是我们后面所谓的 AJAX请求 PHP得到JSON数据，
PHP处理中，我用的是递归算法，返回JSON数据。及完成了。目录结构。
哦对了。
<ol class="dp-c"><li class="alt"><span><span class="vars">$m</span><span>=M(</span><span class="string">'ztree'</span><span>); </span></span></li></ol>
这句代码是thinkphp 实例化 数据操作对象的。
用来查询数据库中，节点是否存在。就是存在子节点，就返回给子节点数组，有几个就加入子节点数组中，查询完了。然后一次性返回，他们就成了同级子节点了。
