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[网页设计]zTree开发下拉树


  最近,因为工作需要一个树形下拉框的组件,经过查资料一般有两种的实现方法。其一,就是使用zTree实现;其二,就是使用easyUI实现。因为公司的前端不是使用easyUI设计的,故这里我选择了zTree来实现下拉树。

这里使用简单的数据格式(即简单的Json格式)类似如下Json:

var zNodes =[      {id:1, pId:0, name:"北京"},      {id:2, pId:0, name:"天津"},      {id:3, pId:0, name:"上海"},      {id:6, pId:0, name:"重庆"},      {id:4, pId:0, name:"河北省", open:true, nocheck:true},      {id:41, pId:4, name:"石家庄"},      {id:42, pId:4, name:"保定"},      {id:43, pId:4, name:"邯郸"},      {id:44, pId:4, name:"承德"},      {id:5, pId:0, name:"广东省", open:true, nocheck:true},      {id:51, pId:5, name:"广州"},      {id:52, pId:5, name:"深圳"},      {id:53, pId:5, name:"东莞"},      {id:54, pId:5, name:"佛山"},      {id:6, pId:0, name:"福建省", open:true, nocheck:true},      {id:61, pId:6, name:"福州"},      {id:62, pId:6, name:"厦门"},      {id:63, pId:6, name:"泉州"},      {id:64, pId:6, name:"三明"}     ];

这里首先需要一个实体bean,用来封装对应查出来的数据,如下:

public class ZtreeNode {  // id  private String id;  // 父id  private String pId;  // 显示名称  private String name;  // 是否打开 (这里默认是不打开的,如果需要打开,设为true)  // private boolean open ;  // 能否选择 (设置节点是否能够选择,默认都能选择,设为true对应的节点不能选择)  // private boolean nocheck ;    /**getter and setter*/}

 这里需要注意的是 pId 中的第二的字母是大写的,如果写成小写的就不能构造成树形结构,所有的都是根节点。

然后,将从数据库中查出来的数据,转换为对应的ztree需要的bean,再转换为相应的Json,代码如下:

// 获取商品分类树 返回json  public String getGoodsCategoryTreeJson() {    List<GoodsCategory> allGoodsCategoryList = goodsCategoryService.getGoodsCategoryTreeJson() ;    List<ZtreeNode> ztreelist = new ArrayList<ZtreeNode>();    for(GoodsCategory gcty : allGoodsCategoryList){      ZtreeNode treenade = new ZtreeNode();      treenade.setId(gcty.getId());      treenade.setpId(gcty.getParent()==null?"":gcty.getParent().getId());      treenade.setName(gcty.getName());      ztreelist.add(treenade);    }    return ajax(ztreelist);  }

 将list转换为对应的Json方法,如下:

用到的Json工具包:

import org.springframework.base.util.JsonUtil;

private static final String HEADER_ENCODING = "UTF-8";private static final boolean HEADER_NO_CACHE = true;private static final String HEADER_TEXT_CONTENT_TYPE = "text/plain";private static final String HEADER_JSON_CONTENT_TYPE = "text/plain";// AJAX输出  protected String ajax(String content, String contentType) {    try {      HttpServletResponse response = initResponse(contentType);      response.getWriter().write(content);      response.getWriter().flush();    } catch (IOException e) {      e.printStackTrace();    }    return NONE;  }  // 根据文本内容输出AJAX  protected String ajax(String text) {    return ajax(text, HEADER_TEXT_CONTENT_TYPE);  }    // 根据操作状态输出AJAX  protected String ajax(Status status) {    HttpServletResponse response = initResponse(HEADER_JSON_CONTENT_TYPE);    Map<String, String> jsonMap = new HashMap<String, String>();    jsonMap.put(STATUS_PARAMETER_NAME, status.toString());    JsonUtil.toJson(response, jsonMap);    return NONE;  }    // 根据操作状态、消息内容输出AJAX  protected String ajax(Status status, String message) {    HttpServletResponse response = initResponse(HEADER_JSON_CONTENT_TYPE);    Map<String, String> jsonMap = new HashMap<String, String>();    jsonMap.put(STATUS_PARAMETER_NAME, status.toString());    jsonMap.put(MESSAGE_PARAMETER_NAME, message);    JsonUtil.toJson(response, jsonMap);    return NONE;  }    // 根据Object输出AJAX  protected String ajax(Object object) {    HttpServletResponse response = initResponse(HEADER_JSON_CONTENT_TYPE);    JsonUtil.toJson(response, object);    return NONE;  }    // 根据boolean状态输出AJAX  protected String ajax(boolean booleanStatus) {    HttpServletResponse response = initResponse(HEADER_JSON_CONTENT_TYPE);    Map<String, Object> jsonMap = new HashMap<String, Object>();    jsonMap.put(STATUS_PARAMETER_NAME, booleanStatus);    JsonUtil.toJson(response, jsonMap);    return NONE;  }  private HttpServletResponse initResponse(String contentType) {    HttpServletResponse response = ServletActionContext.getResponse();    response.setContentType(contentType + ";charset=" + HEADER_ENCODING);    if (HEADER_NO_CACHE) {      response.setDateHeader("Expires", 1L);      response.addHeader("Pragma", "no-cache");      response.setHeader("Cache-Control", "no-cache, no-store, max-age=0");    }    return response;  }

这样前台所需要的数据,就从库里取出,并封装成了对应的Json。

接下来就是前台的实现了,前台需要导入的js和css如下:

<link rel="stylesheet" href="${base}/template/ztree/css/demo.css" type="text/css"><link rel="stylesheet" href="${base}/template/ztree/css/zTreeStyle/zTreeStyle.css" type="text/css"><script type="text/javascript" src="${base}/template/ztree/js/jquery.ztree.core.js"></script>

 这里只有demo.css是自己添加的,其他都是官方制定的,demo.css是将官方的demo用到的css修改的,如下(这里有冗余样式没有删除掉);

 1 div.content_wrap {width: 400px;} 2 div.content_wrap div.left{float: left;} 3 div.content_wrap div.right{float: right;width: 340px;} 4 div.zTreeDemoBackground {text-align:left;} 5  6 ul.ztree {margin-top: 10px;border: 1px solid #617775;background: #fefefe;width:220px;height:360px;overflow-y:scroll;overflow-x:auto;} 7 ul.log {border: 1px solid #617775;background: #f0f6e4;width:300px;height:170px;overflow: hidden;} 8 ul.log.small {height:45px;} 9 ul.log li {color: #666666;list-style: none;padding-left: 10px;}10 ul.log li.dark {background-color: #E3E3E3;}11 12 /* ruler */13 div.ruler {height:20px; width:220px; background-color:#f0f6e4;border: 1px solid #333; margin-bottom: 5px; cursor: pointer}14 div.ruler div.cursor {height:20px; width:30px; background-color:#3C6E31; color:white; text-align: right; padding-right: 5px; cursor: pointer}

然后,就是对应的下拉框:

 1 <div class="content_wrap"> 2   <div class="zTreeDemoBackground left"> 3     <input id="citySel" class="formText" type="text" onclick="showMenu(); return false;" readonly value="" style="width:150px;"/> 4     <input id="treeids" type="hidden" name="goods.goodsCategory.id" > 5     <input type="button" onclick="showMenu();" value="∨"> 6   </div> 7 </div> 8<div id="menuContent" class="menuContent" style="display:none; position: absolute;"> 9  <ul id="treeDemo" class="ztree" style="margin-top:0;"></ul>10 </div>

这里有一个隐藏的文本框用来存放下拉框选择内容对应的id。

对应的脚本如下:

<SCRIPT type="text/javascript">        var setting = {      view: {        dblClickExpand: false      },      data: {        simpleData: {          enable: true        }      },      callback: {        onClick: onClick      },      view: {
          // 不显示对应的图标 showIcon: false } }; function onClick(e, treeId, treeNode) { var zTree = $.fn.zTree.getZTreeObj("treeDemo"), nodes = zTree.getSelectedNodes(), v = ""; ids = ""; nodes.sort(function compare(a,b){return a.id-b.id;}); for (var i=0, l=nodes.length; i<l; i++) { v += nodes[i].name + ","; ids += nodes[i].id + ","; } if (v.length > 0 ) v = v.substring(0, v.length-1); var cityObj = $("#citySel"); cityObj.attr("value", v); // 将选中的id放到隐藏的文本域中 if (ids.length > 0 ) ids = ids.substring(0, ids.length-1); var treeids = $("#treeids"); treeids.attr("value", ids); } function showMenu() { var cityObj = $("#citySel"); var cityOffset = $("#citySel").offset(); $("#menuContent").css({left:cityOffset.left + "px", top:cityOffset.top + cityObj.outerHeight() + "px"}).slideDown("fast"); $("body").bind("mousedown", onBodyDown); } function hideMenu() { $("#menuContent").fadeOut("fast"); $("body").unbind("mousedown", onBodyDown); } function onBodyDown(event) { if (!(event.target.id == "menuBtn" || event.target.id == "menuContent" || $(event.target).parents("#menuContent").length>0)) { hideMenu(); } } var zNodes ; $(document).ready(function(){       // 加载数据 $.ajax({ async : false, cache:false, type: 'POST', dataType : 'json', url: '${base}/admin/goods!getGoodsCategoryTreeJson.action', error: function () { alert('请求失败'); }, success:function(data){ zNodes = data; } }); $.fn.zTree.init($("#treeDemo"), setting, zNodes); }); </SCRIPT>

这样,一个下拉框就做完了。如下图所示:

如果,需要在修改页面中回写相应的下拉列表数据,添加如下的脚本:

<script type="text/javascript">$(document).ready(function(){  if ("${goods.goodsCategory.id}"!="") {    var treeObj = $.fn.zTree.getZTreeObj("treeDemo");    var node = treeObj.getNodeByParam("id", "${goods.goodsCategory.id}" , null);    treeObj.selectNode(node,false , false);    onClick(event,"${goods.goodsCategory.id}",node,true);      }});</script>