vue拖拽组件使用方法详解

<template>
 <div class="transition-container">
 <div class="item" v-for="(item, index) in items" :key="index"
 draggable="true"
 @dragstart="handleDragStart($event, item)"
 @dragover.prevent="handleDragOver($event, item)"
 @dragenter="handleDragEnter($event, item)"
 @dragend="handleDragEnd($event, item)" 
 @click="chooseNav(item)"
 >
 <p class="trans-btn">
 <span v-if="item.problemId">
 <b class="id">
 {{item.problemId}}
 </b>
 {{item.key}}
 </span>
 <span v-else>
 {{item.key}}
 </span>
 <span>
 <i-button v-if="btn" size="small" type="error" style="margin-right: 10px;" @click="deleteItem(item, index)">删除</i-button>
 </span>
 </p>
 </div>
 </div>
</template>
<script>
import './index.less';

export default {
 name: 'transition',
 props: {
 dataSource: Array,
 btn: Boolean,
 },
 data() {
 return {
 items: [],
 dragging: null,
 };
 },
 watch: {
 dataSource(val) {
 this.items = val;
 },
 dragging(val) {
 if (this.dataSource.includes(val)) {
 this.dragging = val;
 } else {
 this.dragging = null;
 }
 },
 },
 methods: {
 handleDragStart(e, item) {
 this.dragging = item;
 },
 handleDragEnd() {
 this.dragging = null;
 this.$emit('hasChanged', this.items);
 },
 // 首先把div变成可以放置的元素，即重写dragenter/dragover
 handleDragOver(e) {
 e.dataTransfer.dropEffect = 'move';// e.dataTransfer.dropEffect="move";//在dragenter中针对放置目标来设置!
 },
 handleDragEnter(e, item) {
 if (this.dragging) {
 e.dataTransfer.effectAllowed = 'move';// 为需要移动的元素设置dragstart事件
 if (item === this.dragging) {
 return;
 }
 const newItems = [...this.items];
 console.log(newItems);
 const src = newItems.indexOf(this.dragging);
 const dst = newItems.indexOf(item);
 newItems.splice(dst, 0, ...newItems.splice(src, 1));
 this.items = newItems;
 }
 },
 chooseNav(val) {
 this.$emit('selectItem', val);
 },
 deleteItem(item, index) {
 this.$emit('deleteItem', item, index);
 },
 editor(item, index) {
 this.$emit('editorItem', item, index);
 },
 },
};
</script>