salesforce 零基础学习（七十）使用jquery tree实现树形结构模式

项目中UI需要用到树形结构显示内容，后来尽管不需要做了，不过还是自己做着玩玩，mark一下，免得以后项目中用到。

实现树形结构在此使用的是jquery的dynatree.js。关于dynatree的使用可以参考：http://wwwendt.de/tech/dynatree/doc/dynatree-doc.html#h4.2

对于树形结构，这里不做太多介绍，树一般需要一个根节点，根节点下面可以有很多子节点或者叶子节点，子结点也可以包含叶子结点或者子节点。我们在设计表结构的时候可以考虑自连接操作，实现节点之间的关联，表结构如下：

我们想要实现的数据结构如下。

对应的数据如下：

在设计树形结构的前台展示时，应该有如下信息：

• 节点名称
• 节点编号
• 当前节点对应的父节点
• 当前节点是否为叶子节点
• 当前节点是否有子节点
• 当前节点如果包含子节点情况下子节点的列表

对于程序设计，主要分成两个步骤：

• 递归将数据存储到自定义结构中；
• 对结构进行json处理，json串应该满足相关的结构，即类似JSONObject{JSONArray[...]}相关模式，可以查看上方链接了解详情。

代码如下：

1.TreeUtil：实现递归对节点关系获取以及json转换；

 public without sharing class TreeUtil {

     // map to hold roles with Id as the key
     private static Map <Id, Tree__c> treeMap;

     // map to hold child roles with parentRoleId as the key
     private static Map <Id, List<Tree__c>> parentNodeToChildNodeMap;

     private static List<NodeWrapper> nodes{get;set;}

     private static JSONGenerator gen {get; set;}

     private static Tree__c rootNode{get;set;}

     static {
         initTreeDatas();
     }

     public static void initTreeDatas() {
         treeMap = new Map<Id,Tree__c>([SELECT IsLeafNode__c, ParentNode__c, Id, Name FROM Tree__c order by ParentNode__c]);
         parentNodeToChildNodeMap = new Map<Id,List<Tree__c>>();
         for(Tree__c tree : treeMap.values()) {
             List<Tree__c> tempList;
             if(parentNodeToChildNodeMap.containsKey(tree.ParentNode__c)) {
                  tempList = parentNodeToChildNodeMap.get(tree.ParentNode__c);
                  tempList.add(tree);
                  parentNodeToChildNodeMap.put(tree.ParentNode__c,tempList);
              } else {
                  tempList = new List<Tree__c>();
                  tempList.add(tree);
                  if(tree.ParentNode__c != null) {
                      parentNodeToChildNodeMap.put(tree.ParentNode__c,tempList);
                  } else {
                     rootNode = tree;
                  }
              }
         }
     } 

     private static void convertNodeToJSON(NodeWrapper nw){
         gen.writeStartObject();
         if(!nw.isLeafNode) {
             gen.writeStringField('title', nw.nodeName);
             gen.writeStringField('key', nw.nodeId);
             gen.writeBooleanField('unselectable', false);
             gen.writeBooleanField('expand', true);
             gen.writeBooleanField('isFolder', true);
             if (nw.hasChildNodes) {
                 gen.writeFieldName('children');
                 gen.writeStartArray();
                 for (NodeWrapper r : nw.childNodes) {
                     convertNodeToJSON(r);
                 }
                 gen.writeEndArray();
             }
         } else {
             gen.writeStringField('title', nw.nodeName);
             gen.writeStringField('key', nw.nodeId);
         }
         gen.writeEndObject();
     }

     public static NodeWrapper createNode(Tree__c tree) {
         NodeWrapper n = new NodeWrapper();
         n.nodeName = tree.Name;
         n.nodeId = tree.Id;
         n.parentNodeId = tree.ParentNode__c;

         if(tree.IsLeafNode__c) {
             n.isLeafNode = true;
             n.hasChildNodes = false;
         } else {
             List<NodeWrapper> nwList = new List<NodeWrapper>();
             if(parentNodeToChildNodeMap.get(tree.Id) != null) {
                 n.hasChildNodes = true;
                 n.isLeafNode = false;
                 for(Tree__c tempTree : parentNodeToChildNodeMap.get(tree.Id)) {
                     nwList.add(createNode(tempTree));
                 }
                 n.childNodes = nwList;
             }

         }
         return n;
     }

     public static String getTreeAndSubTrees() {
         gen = JSON.createGenerator(true);
         NodeWrapper node = createNode(rootNode);
         gen.writeStartArray();
         convertNodeToJSON(node);
         gen.writeEndArray();
         return gen.getAsString();
     }

     public class NodeWrapper {

         //current node name
         public String nodeName{get;set;}

         //current node id
         public String nodeId{get;set;}

         //if current node isn't root,set it's parent parentNodeId
         public String parentNodeId{get;set;}

         //if this node set as a parent node,does it has child node
         public Boolean hasChildNodes{get;set;}

         //if current node is leaf node,set to true
         public Boolean isLeafNode{get;set;}

         //all of child nodes of current node
         public List<NodeWrapper> childNodes{get;set;}

         public NodeWrapper() {
             hasChildNodes = false;
         }
     }

 }

2.TreeController:调用TreeUtil实现数据获取

 public class TreeController {

     public Boolean selectable {get; set;}

     public String selectNodeKeys {get; set;}

     public TreeViewController(){
         selectable = false;
         selectNodeKeys = 'No value selected';
     }

     public String JsonData {get; set;}

     public String getJsonString() {
         if (JsonData == null){
             JsonData = TreeUtil.getTreeAndSubTrees();
         }
         return JsonData;
     }

 }

3.TreeComponent:通过jquery的dyna tree 库实现树形结构实现

 <apex:component controller="TreeController">
     <apex:attribute name="selectable" type="Boolean" assignTo="{!selectable}" description=""/>
     <apex:attribute name="value" type="String" description=""/>
     <apex:attribute name="JsonData" type="String" assignTo="{!JsonData}" description=""/>
     <apex:inputHidden id="selectedKeys" value="{!value}" />
     <apex:includeScript value="{!URLFOR($Resource.DynaTree, 'jquery/jquery.js' )}" />
     <apex:includeScript value="{!URLFOR($Resource.DynaTree, 'jquery/jquery-ui.custom.js' )}" />
     <apex:includeScript value="{!URLFOR($Resource.DynaTree, 'jquery/jquery.cookie.js' )}" />
     <apex:includeScript value="{!URLFOR($Resource.DynaTree, 'src/jquery.dynatree.js' )}" />

     <apex:stylesheet value="{!URLFOR($Resource.DynaTree, 'src/skin/ui.dynatree.css')}" />
     <script type="text/javascript">
     $(function(){

         $("#tree").dynatree({
             onActivate: function(node) {

             },
             persist: false,
             checkbox: {!selectable},
             generateIds: false,
             classNames: {
                 checkbox: "dynatree-checkbox",
                 expanded: "dynatree-expanded"
             },
             selectMode: 3,
             children: {!JsonString},
             onSelect: function(select, node) {
                 var selKeys = $.map(node.tree.getSelectedNodes(), function(node){
                     return node.data.key;
                 });
                 jQuery(document.getElementById("{!$Component.selectedKeys}")).val(selKeys.join(", "));
                 var selRootNodes = node.tree.getSelectedNodes(true);
                 var selRootKeys = $.map(selRootNodes, function(node){
                     return node.data.key;
                 });
             },
         });
     });
     </script>

     <div id="tree"> </div>

 </apex:component>

4.TreeView.page:调用component实现显示

 <apex:page controller="TreeController">
     <apex:form >
         <c:TreeView selectable="true"value="{!selectedValues}" />
         <br/>
         Value:<apex:outputText value="{!selectedValues}" />
         <br/>
         <apex:commandButton value="Get Value" />
     </apex:form>
 </apex:page>

效果展示：

总结：实现树形结构可以有多种js库选择，后台大部分需要做的就是拼json串，通过指定的要求实现前台的展示，了解树形结构如何设计更加重要。本篇只是抛砖引玉，有对树形结构感兴趣的可以将此作为参考并进行优化。内容有错误的地方欢迎指出，篇中有不懂得欢迎留言。