在拖放网格中复制图像答案

【问题标题】：Duplicating Image within Drag and Drop Grid在拖放网格中复制图像
【发布时间】：2017-01-13 02:56:21
【问题描述】：

我有一个拖放功能，您可以将图像从侧边栏拖放到网格中。当图像进入网格时，它会克隆图像。虽然，当我将网格中的图像拖到另一个网格空间时，它会复制它，我不希望它这样做。这是我的代码：

function allowDrop(ev) {
    ev.preventDefault();
}

function drag(ev) {
    ev.dataTransfer.setData("text", ev.target.id);
}

function drop(ev) {
    ev.preventDefault();
    var data = ev.dataTransfer.getData("text");
    var el = ev.target;
    if (!el.classList.contains('dropzone')) {
       el = ev.target.parentNode;
       ev.target.remove();
    }
    el.appendChild(document.getElementById(data).cloneNode(true));
}

function openNav() {
    document.getElementById("mySidenav").style.width = "250px";
    document.getElementsByTagName("body")[0].style.marginLeft = "250px";
}

function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
    document.getElementsByTagName("body")[0].style.marginLeft= "0";
}

#div1, #div2, #div3, #div4{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

#div5, #div6, #div7, #div8{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

#div9, #div10, #div11, #div12{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

#div13, #div14, #div15, #div16{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

.row2 {
	clear: both;
}

.row3 {
	clear: both;
}

.row4 {
	clear: both;
}

body {
  transition: margin .5s;
}

.sidenav {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: #111;
    overflow-x: hidden;
    transition: 0.5s;
    padding-top: 60px;
}

.sidenav a {
    padding: 8px 8px 8px 32px;
    text-decoration: none;
    font-size: 25px;
    color: #818181;
    display: block;
    transition: 0.3s
}

.sidenav a:hover, .offcanvas a:focus{
    color: #f1f1f1;
}
.sidenav .closebtn {
    position: absolute;
    top: 0;
    right: 25px;
    font-size: 36px;
    margin-left: 50px;
}

#main {
    transition: margin-left .5s;
    padding: 16px;
}
.row {
  width:100%;
  display:inline-block;
  margin-bottom:10px;
}

@media screen and (max-height: 450px) {
  .sidenav {
  padding-top: 15px;
  }

  .sidenav a {
  font-size: 18px;
  }
}

<!DOCTYPE html>
<html>
<script>

function allowDrop(ev) {
    ev.preventDefault();
}

function drag(ev) {
    ev.dataTransfer.setData("text", ev.target.id);
}

function drop(ev) {
    ev.preventDefault();
    var data = ev.dataTransfer.getData("text");
    var el = ev.target;
    if (!el.classList.contains('dropzone')) {
       el = ev.target.parentNode;
       ev.target.remove();
    }
    el.appendChild(document.getElementById(data).cloneNode(true));
}

function openNav() {
    document.getElementById("mySidenav").style.width = "250px";
    document.getElementsByTagName("body")[0].style.marginLeft = "250px";
}

function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
    document.getElementsByTagName("body")[0].style.marginLeft= "0";
}

</script>
<body>

 <div id="main">
  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; Materials</span>
</div>

<div id="div1" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div2" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div3" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div4" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div class="row2">

<div id="div5" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div6" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div7" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div8" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>
</div>

<div class="row3">

<div id="div9" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div10" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div11" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div12" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>
</div>

<div class="row4">

<div id="div13" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div14" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div15" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<div id="div16" class="dropzone" ondrop="drop(event)" ondragover="allowDrop(event)"></div>
</div>

<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>

<a href="#">

    <img src="bricks.jpg" draggable="true" ondragstart="drag(event)" id="drag1" width="55" height="55">

   Bricks

</a>

<a href="#">

    <img src="halfbrick.png" draggable="true" ondragstart="drag(event)" id="drag1.3" width="55" height="55">

   Half Brick

</a>

<a href="#">

    <img src="halfbrick2.png" draggable="true" ondragstart="drag(event)" id="drag1.6" width="55" height="55">

   Half Brick

</a>

<a href="#">

    <img src="#" draggable = "true" ondragstart="drag(event)" id="drag2" width="55" height="55">

  Stone

</a>
<a href="#">

    <img src="#" draggable = "true" ondragstart="drag(event)" id="drag3" width="55" height="55">

    Wood

  </a>
  <a href="#">

    <img src="#" draggable="true" ondragstart="drag(event)" id="drag4" width="55" height="55">

  Eraser

  </a>
</div>

</body>
<style>

#div1, #div2, #div3, #div4{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

#div5, #div6, #div7, #div8{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

#div9, #div10, #div11, #div12{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

#div13, #div14, #div15, #div16{
	float: left;
    width: 55px;
    height: 55px;
    border: 1px solid black;
}

.row2 {
	clear: both;
}

.row3 {
	clear: both;
}

.row4 {
	clear: both;
}

body {
  transition: margin .5s;
}

.sidenav {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: #111;
    overflow-x: hidden;
    transition: 0.5s;
    padding-top: 60px;
}

.sidenav a {
    padding: 8px 8px 8px 32px;
    text-decoration: none;
    font-size: 25px;
    color: #818181;
    display: block;
    transition: 0.3s
}

.sidenav a:hover, .offcanvas a:focus{
    color: #f1f1f1;
}
.sidenav .closebtn {
    position: absolute;
    top: 0;
    right: 25px;
    font-size: 36px;
    margin-left: 50px;
}

#main {
    transition: margin-left .5s;
    padding: 16px;
}
.row {
  width:100%;
  display:inline-block;
  margin-bottom:10px;
}

@media screen and (max-height: 450px) {
  .sidenav {
  padding-top: 15px;
  }

  .sidenav a {
  font-size: 18px;
  }
}

我该如何解决这个问题？

【问题讨论】：

标签： javascript html

【解决方案1】：

我发现 ev.target 指的是要删除项目的 div，所以 contains('dropzone') 总是返回 true。

this 为我工作：

function drag(ev, source) {
    ev.dataTransfer.setData("text", ev.target.id);
    ev.dataTransfer.setData("parent", source.parentNode.tagName);

}

function drop(ev) {
    ev.preventDefault();
    var data = ev.dataTransfer.getData("text");
    var parent= ev.dataTransfer.getData("parent");
    // console.log(parent);
    if(parent == "A"){
      el.appendChild(document.getElementById(data).cloneNode(true));
    }
    else{
      ev.target.appendChild(document.getElementById(data));
    }
}

在这里，您可以将拖动项目的 parentNode.tagName('a' 或 'div') 存储到 dataTransfer 中，并在 drop() 函数中访问它，根据该函数克隆该项目或简单地移动它。

【讨论】：

非常感谢！抱歉这么久才回复。