拖动改变顺序

效果： 将被拖动的元素放在拖动结束时的元素后面

实现

jsx

import React, { useState } from 'react';
import styles from './index.less';

let dragStartIndex = 0; // 记录被拖动的元素index
let dragEndIndex = 0; // 鼠标移动时，被悬浮的元素index

export default () => {
  const [list, setLIst] = useState([]);
  const [highLightIndex, setHighLightIndex] = useState(undefined); // 鼠标移动时被悬浮的元素（用来高亮定位）

  // 拖动开始： 记录被拖动元素
  const onDragStart = (index) => {
    dragStartIndex = index;
  };

  // 拖动进入事件： 记录被悬浮的元素
  const onDragEnter = (index) => {
    dragEndIndex = index;
    setHighLightIndex(index);
  };

  // 拖动结束：改变数组，去掉dragStartIndex，插入dragEndIndex后面位置；
  const onDragEnd = () => {
    if (dragEndIndex === dragStartIndex) {
      setHighLightIndex(undefined);
      return;
    }

    const tabHeadersCopy = [...list];
    const dragingTab = tabHeadersCopy[dragStartIndex];

    // 为了实现拖动元素放到被浮动的元素后面，从前往后拖动和从后往前拖动，增删数组稍有差异
    if (dragEndIndex > dragStartIndex) {
      tabHeadersCopy.splice(dragStartIndex, 1);
      tabHeadersCopy.splice(dragEndIndex, 0, dragingTab);
    } else {
      tabHeadersCopy.splice(dragEndIndex + 1, 0, dragingTab);
      tabHeadersCopy.splice(dragStartIndex + 1, 1);
    }

    setLIst(tabHeadersCopy);
    setHighLightIndex(undefined);
  };

  return (
    <div className={styles['tabs-container']}>
      {list &&
        list.length > 0 &&
        list.map((tab, index) => (
          <div
            key={tab.id}
            draggable={true}
            onDragStart={() => onDragStart(index)}
            onDragEnd={onDragEnd}
            onDragEnter={() => onDragEnter(index)}
            style={{ borderColor: index === highLightIndex ? 'red' : '' }}
          >
            {tab.name}
          </div>
        ))}
    </div>
  );
};

参考实现： react中实现拖拽排序react-dnd