simple-react-draggable

简单的可拖拽的react组件, 不依赖任何第三方的库

example(demo)

结合antd Select折中的支持排序方案(理想的情况重构Select组件)

解决什么问题?

• 来源于运营同学的需求;
• 在用antd的select组件时, mode:multiple时, 选中的tag不能排序; 有时需要对选中数据执行调整顺序时, 需要删掉数据,然后在添加数据;

Usage

npm/cnpm i simple-react-draggable

• Props

| Attribute | Description | Type | Accepted Values | Default | | ------------ | ------------ | ---------- | ------------------ | ------- | | list | data | Array | [{id,name}] | [] | | option | config | {} | | | | className | container style | css string | any | | | itemClassName| each item style | css string | any | | | onMove | listener | function | callback | |

• example

  import Draggable from 'simple-react-draggable';
  const list = [{
    id: 1,
    name: '测试1'
  },{
    id: 2,
    name: '测试2'
  },{
    id: 3,
    name: '测试3'
  },{
    id: 4,
    name: '测试4'
  },{
    id: 5,
    name: '测试6'
  },{
    id: 7,
    name: '测试7'
  }];

  <Draggable list={list}/>

参数说明

配置:

• option: (可选)

  • offsetX: item的左右间隔距离
  • offsetY: item的上下间隔距离
  • width: item的宽度
  • height: item的高度
  • defaultOption:

      const defaultOption = {
          width: 50, 
          height: 20,
          offsetX: 3,
          offsetY: 3
      };

• itemClassName: (可选)

  • 移动项的className
  • 移动项默认的样式

      .draggable-item {
        background: #f3f3f3;
        border-radius: 4px;
        overflow: hidden;
        cursor: default;
        font-size: 12px;
        color: rgba(0,0,0,0.65);
        text-align: center;
      }

• className: (可选)

  • 容器的样式
  • 容器的样式

  .wrapper {
    background: #fff;
    border-radius: 4px;
    border: 1px solid #d9d9d9;
    box-sizing: border-box;
    padding: 0;
    margin: 0;
  }

• list: 需要排序的数据

  • type: [{id,name}]

• onMove: 把移动后的数据返回

  • type: callback

  • return: [{id, name}]

实现的思路

• 总的思路: 找到要移动的数据的index和目标位置的元素的index, but how?

  1. 每一个item元素bind onDragStart监听事件; 并记录每个元素的index(代码为position); 这一步获取移动数据的index

   list.forEach((item,index) => {
     items.push(
       <div key={item.id}
         onDragStart = {(event) => this.onDragStart(event, index)}
         draggable
         style={{marginTop: offsetY, marginLeft: offsetX, width, height, lineHeight: height+'px'}}
         className={itemCls}
       >
         {item.name}
       </div>
     );
   })
     
   // onDragStart 记录index
    event.dataTransfer.setData("position", position);

  2. 获取目标位置元素的index: 容器中监听onDrop事件, 使用onDragOver防止事件冒泡; onDrap事件实现:

   onDrop = (event) => {
       let {list} = this.state,
           position = event.dataTransfer.getData("position"),
           targetIndex = this.calculateTargetIndex(event.target),
           removeItem;
       let {onMove} = this.props;
       if(targetIndex !== -1){
           removeItem = list.splice(position, 1)[0];
           list.splice(targetIndex, 0, removeItem);
           this.setState({list});
           onMove && onMove(list)
       }
   }

  3. 在React计算元素的物理位置

  1).计算拖拽容器的x,y,以及每一行能显示多少移动元素

   calculateDragContainer(){
       let { option: {offsetX, width} } = this.state;
       let c = ReactDOM.findDOMNode(this.refs.draggableContainer).getBoundingClientRect(),
           col = parseInt((c.width - offsetX) / (width + offsetX));
       return {
       x: c.x,
       y: c.y,
       col
       }
   }

  2). 计算item元素的x,y

      calculateDragItem(target){
          var t = ReactDOM.findDOMNode(target).getBoundingClientRect();
          return {x: t.x, y: t.y}
      }

  3). 计算每一个list中的i数据的行列值

  calculateIndexRowCol(i, maxCol) { // index row col
      let row, col;
      row = Math.ceil(i / maxCol);
      col = i % maxCol;
      if(col === 0) {
      col = maxCol;
      }
      return {row, col};
  }

  4). 计算目标位置的list元素的index

  calculateTargetIndex(target){// 获取目标元素的index
      let { list, option: {width, height, offsetX, offsetY} } = this.state,
          c = this.calculateDragContainer(),
          t = this.calculateDragItem(target),
          targetIndex = -1,targetX,targetY, i,
          len = list.length;
      if(t.x !== c.x && list.length > 0){ // 鼠标落在目标item上
      for(i = 1; i <= len; ++i){
          let {row, col} = this.calculateIndexRowCol(i, c.col);
              targetX = ((col - 1) * width + col * offsetX) + c.x;
              targetY = ((row - 1) * height + row * offsetY) + c.y;
          if(targetX === t.x && targetY === t.y){
          targetIndex = i - 1;
          break; 
          }
      }
      }
      return targetIndex;
  }