需求：树上添加向下按钮，再不调用接口的情况下，调整树的顺序结构
遇到的问题：第一次点击更新的，数据和视图是调整好的，再次点击页面调整顺序，只有数据被调整了，视图没有发生改变。
<el-treeref="tree":data="treeData"highlight-currentnode-key="id":props="props":default-expanded-keys="showList"@node-click="clicktree"><span slot-scope="{node, data }" class="custom-tree-node"><img v-if="data.seq_img" :src="hanleImgShow(data?.seq_img)" width="20" height="20"><span style="display:inline-block;padding-left:5px;">{{ data?.seq_name_chn }}</span><el-button v-if="data.seq_img" type="text" icon="el-icon-arrow-down" @click="moveDown(node,data,data?.seq_num)" /></span></el-tree> moveDown(node, data, num) {const seqNum = Number(num)const childrenLength = node.parent.data.children.lengthconst childrenList = node?.parent?.data?.children// seqNum 这个值去判断if (childrenLength == seqNum) {return this.$message.warning('不可以下移')}const treeList = this.treeCreatedData // 存放数据的, 这个里面的children是存放的序数据const targetIndex = childrenList.findIndex(item => item.seq_num == num)if (targetIndex !== -1) {this.moveItemAndUpdateSeqNum(childrenList, targetIndex) // 将第三项移动到第一位}},moveItemAndUpdateSeqNum(list, index) {if (index < list.length - 1 && index >= 0) {const temp = list[index]list[index] = list[index + 1]list[index + 1 ] = tempthis.$nextTick(() => {for (let i = index; i <= index + 1; i++) {list[i].seq_num = (i + 1).toString()}console.log(list, 'list382')this.treeCreatedData[0].children[0].children = listthis.treeData = this.treeCreatedDatathis.$forceUpdate() })}},这样写，只会更新第一次的视图，后续点击 视图没有发生改变；最后找到的方法是使用ref找树的方法 去修改。
moveItemAndUpdateSeqNum(list, index) {if (index < list.length - 1 && index >= 0) {const temp = list[index]list[index] = list[index + 1]list[index + 1 ] = tempthis.$nextTick(() => {for (let i = index; i <= index + 1; i++) {list[i].seq_num = (i + 1).toString()}console.log(list, 'list382')this.treeCreatedData[0].children[0].children = listthis.treeData = this.treeCreatedDatathis.$refs.tree.root.setData(this.treeData) //使用这个 去更新树节点的数据})}},
