jQuery EasyUI 树形菜单 - 树形菜单加载父/子节点

通常表示一个树节点的方式就是在每一个节点存储一个 parentid。这个也被称为邻接列表模型。直接加载这些数据到树形菜单（Tree）是不允许的。但是我们可以在加载树形菜单之前，把它转换为标准标准的树形菜单（Tree）数据格式。树（Tree）插件提供一个 'loadFilter' 选项函数，它可以实现这个功能。它提供一个机会来改变任何一个进入数据。本教程向您展示如何使用 'loadFilter' 函数加载父/子节点到树形菜单（Tree）。

父/子节点数据

    [
    {"id":1,"parendId":0,"name":"Foods"},
    {"id":2,"parentId":1,"name":"Fruits"},
    {"id":3,"parentId":1,"name":"Vegetables"},
    {"id":4,"parentId":2,"name":"apple"},
    {"id":5,"parentId":2,"name":"orange"},
    {"id":6,"parentId":3,"name":"tomato"},
    {"id":7,"parentId":3,"name":"carrot"},
    {"id":8,"parentId":3,"name":"cabbage"},
    {"id":9,"parentId":3,"name":"potato"},
    {"id":10,"parentId":3,"name":"lettuce"}
    ]

使用 'loadFilter' 创建树形菜单（Tree）

    $('#tt').tree({
        url: 'data/tree6_data.json',
        loadFilter: function(rows){
            return convert(rows);
        }
    });

转换的实现

    function convert(rows){
        function exists(rows, parentId){
            for(var i=0; i<rows.length; i++){
                if (rows[i].id == parentId) return true;
            }
            return false;
        }
        
        var nodes = [];
        // get the top level nodes
        for(var i=0; i<rows.length; i++){
            var row = rows[i];
            if (!exists(rows, row.parentId)){
                nodes.push({
                    id:row.id,
                    text:row.name
                });
            }
        }
        
        var toDo = [];
        for(var i=0; i<nodes.length; i++){
            toDo.push(nodes[i]);
        }
        while(toDo.length){
            var node = toDo.shift();    // the parent node
            // get the children nodes
            for(var i=0; i<rows.length; i++){
                var row = rows[i];
                if (row.parentId == node.id){
                    var child = {id:row.id,text:row.name};
                    if (node.children){
                        node.children.push(child);
                    } else {
                        node.children = [child];
                    }
                    toDo.push(child);
                }
            }
        }
        return nodes;
    }