效果：

实现

<template>
  <div class="box">
    <div
      v-for="(item, index) in items"
      :key="item.id"
      class="item"
      :style="{ order: item.order }"
      :draggable="true"
      @dragstart="onDragStart(index)"
      @dragover.prevent="onDragOver"
      @drop="onDrop(index, $event)">
      {{ item.name }}
    </div>
  </div>
</template>

<script setup>
import { ref } from "vue";

const items = ref([
  { id: 1, name: "Item 1", order: 1 },
  { id: 2, name: "Item 2", order: 2 },
  { id: 3, name: "Item 3", order: 3 },
]);
let draggedIndex = null;

const onDragStart = (index) => {
  draggedIndex = index;
};

const onDragOver = (event) => {
  event.preventDefault();
};

const onDrop = (targetIndex, event) => {
  event.preventDefault();
  if (draggedIndex !== targetIndex) {
    const draggedOrder = items.value[draggedIndex].order;
    const targetOrder = items.value[targetIndex].order;
    items.value[draggedIndex].order = targetOrder;
    items.value[targetIndex].order = draggedOrder;
  }
};
</script>

<style>
.box {
  display: flex;
  flex-wrap: wrap;
}

.item {
  width: 100px;
  height: 100px;
  border: 1px solid #ccc;
  background-color: #f3f3f3;
  margin: 5px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 16px;
  cursor: move;
  user-select: none;
  transition: background-color 0.3s;
}
.item:active {
  background-color: #ddd;
}
</style>

核心就是 flex布局 的 order属性