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);
div.content_wrap {width: 400px;} div.content_wrap div.left{float: left;} div.content_wrap div.right{float: right;width: 340px;} div.zTreeDemoBackground {text-align:left;} ul.ztree {margin-top: 10px;border: 1px solid #617775;background: #fefefe;width:220px;height:360px;overflow-y:scroll;overflow-x:auto;} ul.log {border: 1px solid #617775;background: #f0f6e4;width:300px;height:170px;overflow: hidden;} ul.log.small {height:45px;} ul.log li {color: #666666;list-style: none;padding-left: 10px;} ul.log li.dark {background-color: #E3E3E3;} /* ruler */ div.ruler {height:20px; width:220px; background-color:#f0f6e4;border: 1px solid #333; margin-bottom: 5px; cursor: pointer} 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:
<div> <div> <input id="citySel" type="text" readonly value=""/> <input id="treeids" type="hidden" name="goods.goodsCategory.id" > <input type="button" value="∨"> </div> </div> 8<div id="menuContent"> <ul id="treeDemo"></ul> </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>
以上就是本文的全部内容,希望对大家学习zTree插件有所帮助。