两个元素之间的箭头

Question

我想要一个箭头连接展开的弹性项目。（弹性项目在点击它们时会扩展到一个完整的行。请运行代码。）。箭头必须是连接最后一个未展开元素和展开元素的向下箭头。

  2nd element clicked:
  
  |--------|                       
  |        |-----|                      1st row                 
  |1st ele |     |             
  |--------|     |    
                \/
  |------------------------|
->|                        |-->         2nd row
  |      2nd               |
  |------------------------|
  
  
  |--------|      |--------|                   
->|        |----->|        |----->      3rd row        
  | 3rd    |      | 4th    |                 
  |--------|      |--------|        
  

$('#clickMe').click(function() {
    $('#Demosss').append($('<li  class="flex-item">').text('abc'))
    $(this).insertAfter($('[class^="flex-item"]').last());
});

$(document).on('click', '.flex-item' ,function(){
  $(this).toggleClass('flexActive')
})

.fulex{
  display: flex;
  //white-space: nowrap;
  width: 100%;
  height: 100%;
  position: relative;
}
.flex-container {
  padding: 0;
  margin: 0;
  //display:none;
  list-style: none;
  -webkit-flex-direction: row;
  /* Safari */
  flex-direction: row;
  flex-wrap: wrap;
//  width:600px;
}

.flex-item {
  background: green;
  //display:flex;
  padding: 5px;
  width: 100px;
  height: 150px;
  margin-top: 10px;
  margin-right: 15px;
  margin-bottom:50px;
  line-height: 150px;
  color: white;
  font-weight: bold;
  font-size: 3em;
  text-align: center;
  display: inline-block;
  position: relative;
}

.flexActive {
  width: auto;
  display: block;
  flex: 1 1;
  margin-right: 0;
}

ul li {
  display: inline;
}

.flex-item {
  margin-left: .75em;
}

.flex-item:not(:first-child):before {
  content: '\21E2';
  color: black;
  position: absolute;
  top: 50%;
  left: 0;
  transform: translate(-100%, -50%);
  z-index: 1;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="fulex">

<ul id="Demosss" class="flex-container">

<!-- add LI here -->
</ul>


<button id="clickMe">Click Me</button>
</div>

Answer 1

由于您想向目标元素添加向下箭头，您可以将css属性添加到flexActive。

将此添加到CSS。

.flexActive:after{
    content: '\21E2';
    color:black;
    position:absolute;
    top:-80px;
}

<强> FIDDLE