drag 拖放API

[yongheng2016]

SortableJS element ui 的sortableJs封装

<div id="demo1">
  <ul class="panel-list">
    <li class="panel-item"></li>
    <li class="panel-item"></li>
    <li class="panel-item"></li>
    <li class="panel-item"></li>
    <li class="panel-item"></li>
  </ul>
  <h2>拖拽下面的方块到上面任意容器中</h2>

  <!-- 设置draggable使元素成为可拖拽元素 -->
  <span class="movable" id="demo1-src" draggable="true"></span>

  <style>
  #demo1 {
    margin: 20px;
  }
  #demo1 .panel-list {
    overflow: hidden;
    list-style: none;
    margin: 0;
    padding: 0;
  }
  #demo1 .panel-item {
    float: left;
    margin-right: 30px;
    width: 100px;
    height: 100px;
    background: #ddd;
    border: 1px solid #ddd;
  }
  #demo1-src {
    display: inline-block;
    width: 50px;
    height: 50px;
    background: purple;
  }
  #demo1 .over {
    border: 1px dashed #000;
    -webkit-transform: scale(0.8, 0.8);
  }
  </style>
  <script>
  (function () {

    var dnd = {
      // 初始化
      init: function () {
        var me = this;
        me.src = document.querySelector('#demo1-src');
        me.panelList = document.querySelector('.panel-list');

        // 为拖拽源监听dragstart,设置关联数据
        me.src.addEventListener('dragstart', me.onDragStart, false);

        // 拖拽鼠标移入元素,在拖放目标上设置视觉反馈
        me.panelList.addEventListener('dragenter', me.onDragEnter, false);

        // 取消元素dragover默认行为,使其可拖放
        me.panelList.addEventListener('dragover', me.onDragOver, false);

        // 拖拽移出元素,清除视觉反馈
        me.panelList.addEventListener('dragleave', me.onDragLeave, false);

        // 鼠标释放,在拖放目标上接收数据并处理
        me.panelList.addEventListener('drop', me.onDrop, false);
      },
      onDragStart: function (e) {
        e.dataTransfer.setData('text/plain', 'demo1-src');
      },
      onDragEnter: function (e) {
        if (e.target.classList.contains('panel-item')) {
          e.target.classList.add('over');
        }
      },
      onDragLeave: function (e) {
        if (e.target.classList.contains('panel-item')) {
          e.target.classList.remove('over');
        }
      },
      onDragOver: function (e) {
        e.preventDefault();
      },
      onDrop: function (e) {
        var id = e.dataTransfer.getData('text/plain');
        var src = document.getElementById(id);
        var target = e.target;
        if (target.classList.contains('panel-item')) {
          target.appendChild(src);
          target.classList.remove('over');
        }
      }

    };

    dnd.init();
  }());
  </script>
</div>

---

<div id="demo2">
  <h3>从文件夹中拖拽图片到下面的区域进行预览</h3>
  <ul class="preview"></ul>
  <style>
  #demo2 {
    margin: 20px;
  }
  #demo2 .preview {
    height: 300px;
    background: #ddd;
  }
  #demo2 li {
    float: left;
    margin-left: 40px;
  }
  #demo2 img {
    max-height: 150px;
    width: auto;
  }
  </style>

  <script>
  (function (w) {
    var doc = w.document;

    var dnd = {
      init: function () {
        var me = this;
        var preview = doc.querySelector('#demo2 .preview');

        preview.addEventListener('dragover', function (e) {
          e.preventDefault();
        }, false);

        preview.addEventListener('drop', function (e) {
          // 操作系统拖放文件到浏览器需要取消默认行为
          e.preventDefault();

          [].forEach.call(e.dataTransfer.files, function (file) {
            if (file && file.type.match('image.*')) {
              var reader = new FileReader();

              reader.onload = function (e) {
                var img = doc.createElement('img');
                img.src = e.target.result;
                var li = doc.createElement('li');
                li.appendChild(img);
                preview.appendChild(li);
              };

              reader.readAsDataURL(file);
            }
          });
        }, false);
      }

    };

    dnd.init();
  }(window));
  </script>
</div> <!-- demo2 -->

• https://developer.mozilla.org/zh-CN/docs/Web/API/HTML_Drag_and_Drop_API
• https://github.com/webplus/blog/issues/5