CSS实现树形结构 + js加载数据

看到一款树形结构，比较喜欢它的样式，就参照它的外观自己做了一个，练习一下CSS。

做出来的效果如下：

li { position: relative; padding: 5px 0; margin:0; }
#tree-div.tree>ul { padding: 0; margin: 0 }
.tree>ul ul>li::after { content: " "; position: absolute; top: 20px; left: -45px; width: 45px; border: none; border-top: 1px solid #ddd }
.tree ul>li:not(:last-child)::before { content: " "; position: absolute; top: 0; left: -45px; height: 100%; border: none; border-left: 1px solid #ddd }
.tree ul>li:last-child::before { content: " "; position: absolute; top: 0; left: -45px; height: 20px; border: none; border-left: 1px solid #ddd }
.tree span:hover,.tree span:hover+ul span { color: #fff; background-color: orange }
.tree span:hover,.tree span:hover+ul span,.tree span:hover+ul li::before,.tree span:hover+ul li::after { border-color: orange }
.tree .fa::before { margin-right: 5px }
.tree .fa-minus-circle,.tree .fa-plus-circle { cursor: pointer }
-->

• 拉莫小学
  • 一年级
    • 一班
    • 二班
  • 二年级
  • 三年级
    • 一班
    • 二班
    • 三班

树的dom结构：

<div class="tree">
    <ul>
        <li>
            <span><i class="fa fa-minus-circle"></i>拉莫小学</span>
            <ul>
                <li>
                    <span><i class="fa fa-minus-circle"></i>一年级</span>
                    <ul>
                        <li><span>一班</span></li><li><span>二班</span></li>
                    </ul>
                </li>
                <li>
                    <span>二年级</span>
                </li>
                <li>
                    <span><i class="fa fa-minus-circle"></i>三年级</span>
                    <ul>
                        <li><span>一班</span></li>
                        <li><span>二班</span></li>
                        <li><span>三班</span></li>
                    </ul>
                </li>
            </ul>
        </li>
    </ul>
</div>

CSS代码：

/** tree.css zyj 2018.4.21 */
ul,li{list-style-type:none;}
.tree{display:block;position:relative;padding:5px 15px;}
.tree span{display:inline-block;box-sizing:border-box;height:30px;line-height:28px;min-width:60px;text-align:center;color:#888;border:1px solid #ddd;border-radius:5px;padding:0 8px;}
.tree ul{position:relative;padding-left:60px;margin:;}
.tree ul>li{position:relative;padding:5px 0;}
.tree>ul{padding:;margin:;}
/** 水平方向连线 */
.tree>ul ul>li:after{content:' ';position:absolute;top:20px;left:-45px;width:45px;border:none;border-top:1px solid #ddd;}
/** 垂直方向连线 */
.tree ul>li:not(:last-child):before{content:' ';position:absolute;top:;left:-45px;height:100%;border:none;border-left:1px solid #ddd;}
.tree ul>li:last-child:before{content:' ';position:absolute;top:;left:-45px;height:20px;border:none;border-left:1px solid #ddd;}
/** 控制鼠标移上去的颜色 */
.tree span:hover, .tree span:hover+ul span{color:#fff;background-color:orange;}
.tree span:hover, .tree span:hover+ul span, .tree span:hover+ul li:before, .tree span:hover+ul li:after{border-color:orange;}
/** 折叠图标 */
.tree .fa:before{margin-right:5px;}
.tree .fa-minus-circle, .tree .fa-plus-circle{cursor:pointer;}

里面引的fontawesome图标没法加载进来，导致折叠按钮显示不出，下面是原始树状图的截图：

数据是我用JS加载的，写了个加载数据的tree.js文件，源码如下：

/** tree.js zyj 2018.4.22 */
(function(name){
    var tree, outer, defaultDateFormat;

    outer = {
        setData : setData,
    };

    defaultDateFormat = {
            unfold : true,
            name : 'name',
            childName : 'children'
    };

    function getDataFormat(dataFormat){
        var index;
        if(!dataFormat){
            return defaultDateFormat;
        }
        for(index in defaultDateFormat){
            dataFormat[index] = typeof dataFormat[index] == 'undefined'? defaultDateFormat[index] : dataFormat[index];
        }
        return dataFormat
    }

    function initTreeJs(name){
        var tree;
        if(checkTreeNameUsed(name)){return;}
        window[name] = outer;
        initFoldIcon($('.tree'));
    }

    function checkTreeNameUsed(name){
        if(window[name]){
            console.error("The window object name [" + name + "] has been used, tree.js can't be loaded! You can try another name." );
            return true;
        }
        return false;
    }

    function initFoldIcon(target){
        target.off('click', 'span>i.fa').on('click', 'span>i.fa', function(e){
            var ele = $(e.target);
            if(ele.hasClass('fa-minus-circle')){
                ele.removeClass('fa-minus-circle').addClass('fa-plus-circle').parent().next('ul').hide(200);
            }else if(ele.hasClass('fa-plus-circle')){
                ele.removeClass('fa-plus-circle').addClass('fa-minus-circle').parent().next('ul').show(200);
            }
        })
    }

    function getJqueryObjectBySelector(selector){
        var ele = $(selector);
        if(typeof selector != 'string'){
            console.error("The first parameter jquery selector [" + selector +  "] must be a string!" );
            return;
        }
        if(!ele.hasClass('tree')){
            ele = ele.find('.tree');
        }
        if(ele.length != 1){
            console.error("The selector [" + selector +  "] expect only one element!" );
            return;
        }
        return ele;
    }

    function setData(selector, data, dataFormat){
        var ele = getJqueryObjectBySelector(selector);
        if(!ele){return;}
        if(!data){return;}
        if(!data.length){
            data = [data];
        }
        dataFormat = getDataFormat(dataFormat);
        dataFormat.topElement = true;
        ele.empty().append(getTreeList(data, dataFormat));
        initFoldIcon(ele);
    }

    function getTreeList(data, dataFormat){
        var i, single, name, children, childDataFormat,
            array = [];
        childDataFormat = dataFormat.child || dataFormat;
        if(dataFormat.unfold){
            array.push('<ul>');
        }else if(dataFormat.topElement){
            dataFormat.topElement = false;
            array.push('<ul>');
        }else{
            array.push('<ul style="display:none;">');
        }
        for(i=0; i<data.length; i++){
            single = data[i];
            if(typeof dataFormat.name == 'function'){
                name = dataFormat.name(single);
            }else if(typeof dataFormat.name == 'string'){
                name = single[dataFormat.name];
            }else{
                name = single['name'];
            }
            if(typeof dataFormat.childName == 'string'){
                children = single[dataFormat.childName];
            }else{
                children = single['children'];
            }
            array.push('<li>');
            array.push('<span>');
            if(children && children.length > 0){
                if(dataFormat.unfold){
                    array.push('<i class="fa fa-minus-circle"></i>');
                }else{
                    array.push('<i class="fa fa-plus-circle"></i>');
                }
                array.push(name);
                array.push('</span>');
                array.push(getTreeList(children, childDataFormat));
            }else{
                array.push(name);
                array.push('</span>');
            }
            array.push('</li>');
        }
        array.push('</ul>');
        return array.join('');
    }

    initTreeJs(name);
}('tree'))

偷懒没写注释，tree.js中目前只写了一个对外的接口 tree.setData(selector, data, dataFormat) 。参数selector是jQuery选择器，data是数据，dataFormat是数据格式。

比如加载上图的数据：

var dataTest = {
name:'拉莫小学',
children:[
   {
       name:'一年级',
       children:[
           {name:'一班'},
           {name:'二班'}
       ]
   },
   {
       name:'二年级'
   },
   {
       name:'三年级',
       children:[
           {name:'一班'},
           {name:'二班'},
           {name:'三班'}
       ]
   }
]
};

tree.setData('.tree', dataTest);

由于后台加载的数据不一定是按照{name:'*', children:[{name:'*'},...]}这种结构，所以留了dataFormat参数，自己去定义数据格式。

简单举个例子，假如后台数据格式是

var data =
{
    id : '1',
    title : '百度',
    url : 'http://www.baidu.com',
    subWeb :
    [
         {
             id : '2',
             title : '百度新闻',
             url : 'http://news.baidu.com'
         },
         {
             id : '3',
             title : '百度知道',
             url : 'http://zhidao.baidu.com'
         },
         {
             id : '4',
             title : '百度图片',
             url : 'http://image.baidu.com'
         },
     ]
}

那么dataFormat可以定义为

var dataFormat =
{
    name : function(data){
        return '<a href="' + data.url + '">' + data.title + '</a>';
    },
    childName : 'subWeb'
}

至于效果，读者自己去试咯。