课程筛选条件分为三种情况：一级分类、二级分类、课程难度，逻辑如下：

1、直接进入课程页，展示所有一级、二级、课程难度
2、如果点击了一级，展示对应一级下的二级并展示此一级下所有课程
3、如果直接点击二级，那么一级不动，展示对应二级所有课程
4、点击一级、二级、课程难度，当前的class类要对应添加

完整代码如下：

<template>
	<Header></Header>
	<div class='coursemain'>
		<div class="course-main">
			<section class="search-container">
		        <div class="search-item">
		          <div class="title-name">课程方向：</div>
		          <div class="all-items">
		            <el-tag
		                class="category-poniter"
		                effect="plain"
		                type="info"
		            >全部</el-tag>
		            <el-tag
		            	  v-for='item in firstCategorys'
		            	  :key='item.id'
		                :class="currentId['fcategory'].id==item.id?'category-poniter':'category-poniter-item'"
		                effect="plain"
		                type="info"
                    @click='buildingCondition("fcategory",item.id)'
		            >
		            	{{ item.categoryName }}
		            </el-tag>
		        </div>
		        </div>
		        <div class="search-item search-item-transition" style="top: 45px;">
		          <div class="title-name">课程分类：</div>
		          <div class="all-items">
		             <el-tag
		                class="category-poniter"
		                effect="plain"
		                type="info"
		            >全部</el-tag>
		            <el-tag
		            	v-for='item in secondCategorys'
		            	:key='item.id'
		              :class="currentId['scategory'].id==item.id?'category-poniter':'category-poniter-item'"
		              effect="plain"
		              type="info"
                  @click='buildingCondition("scategory",item.id)'
		            >  {{ item.categoryName }}
		            </el-tag>
		          </div>
		        </div>
		        <div class="search-item" style="top: 90px;">
		          <div class="title-name">课程难度：</div>
		          <div class="all-items">
		            <el-tag
		                class="category-poniter"
		                effect="plain"
		                type="info"
		            >全部</el-tag>
		            <el-tag
		            	v-for='item in courseLevel'
		            	:key='item.id'
		              :class="currentId['clevel'].id==item.code?'category-poniter':'category-poniter-item'"
		              effect="plain"
		              type="info"
                    @click='buildingCondition("clevel",item.code)'
		            >  {{ item.text }}
		            </el-tag>
		          </div>
		        </div>
     		</section>
		</div>
		<div class='main-container'>
			<div class="container-top">
		        <ul class="all">
		          <li class="item">综合</li>
		          <li class="item split">|</li>
		          <li class="item">最新课程</li>
		          <li class="item split">|</li>
		          <li class="item">最多购买 </li>
		          <li class="item split">|</li>
		          <li class="item-price">
		            <span>价格</span>  
		            <span class="arrow">
		              <i
		                  class="el-icon-caret-top"
		              ></i>
		              <i
		                  class="el-icon-caret-bottom"
		              ></i>
		            </span>
		          </li>
		        </ul>
		        <ul class="right">
		          <li class="right-item">
		            <el-radio-group>
		              <el-radio label="1">免费课程</el-radio>
		              <el-radio label="2">会员课程</el-radio>
		            </el-radio-group>
		          </li>
		        </ul>
		      </div>
		      <div class="container-body">
		        <div class="newCourseContent">
		          <ul class="courseUl">
		            <li 
		            	class='courseItem'
		            	v-for='item in courseList'
		            	:key='item.id'
		            >
						<div class='courseInfo'>
							<div class='courseBg'>
								<img :src="item.courseCover">
							</div>
							<div class="courseName">{{item.courseName}}</div>
	                        <div class="courseDegree">{{ courseTypeFn(item.courseLevel) }} · {{item.purchaseCounter + item.purchaseCnt}}人报名</div>
							
	                        <div class="coursePriceZero" v-if="item.discountPrice == 0">
	                            <div class="pricefree">免费学习</div>
	                            <img src="../assets/img/free.png" alt="">
	                        </div>

	                        <div class="coursePrice" v-else-if="item.isMember == 1">
	                            <div class="courseMemberbg"><span class="courseMember">会员免费</span></div>
	                            <div class="price">¥ {{item.discountPrice}}</div>
	                        </div>

	                        <div class="coursePricePri" v-else>
	                            <div class="pricePri">¥ {{item.discountPrice}}</div>
	                        </div>
						</div>
					</li>
		          </ul>
		        </div>
		        <div class='pages'>
			    	<el-pagination 
			    		background 
			    		layout="prev, pager, next" 
			    		:total="total" 
			    		@current-change='handleCurrentChange'
			    	/>
			    </div>
		   	</div>
		</div>
	</div>
	<Foot></Foot>
</template>


<script setup>
let currentId = reactive({
  fcategory:{id:''},
  scategory:{id:''},
  clevel:{id:''}
})
//mixin
import mixin from '../mixins/courseType.js'
let { courseTypeFn } = mixin();
//组件
import Header from '../components/common/Header.vue'
import Foot from '../components/common/Foot.vue'
//api
import { getFirstCategorys , getSecondCategorys , searchCourse } from '../utils/api/courseManage'
//获取一级分类的数据
let firstCategorys = ref([]);
//获取二级分类的数据
let secondCategorys = ref([]);
let category = reactive({
    categoryId:-1
})

//请求二级分类
const getSecondCategorysFn = (category)=>{
  getSecondCategorys(category).then(res=>{
    secondCategorys.value = res.data.list;
  })
}

//课程难度的数据
let courseLevel = ref([
	{text: '初级',code: '1'}, 
  {text: '中级',code: '2'},
 	{text: '高级',code: '3'}
]);
//查询课程的数据
let courseList = ref([]);
//课程的总数量
let total = ref(0);
let queryCoursePrams = reactive({
	pageNum:1,
	pageSize:8,
  entity:{
    firstCategory:'',
    secondCategory:'',
    courseLevel:''
  }
})
const querySearchCourse = ()=>{
	searchCourse(queryCoursePrams).then(res=>{
		courseList.value = res.data.pageInfo.list;
		total.value = res.data.pageInfo.total;
	})
}
//生命周期
onBeforeMount(()=>{
	//请求一级分类
	getFirstCategorys().then(res=>{
		firstCategorys.value = res.data.list;
	})
	//请求二级分类
	getSecondCategorysFn(category);
	//查询所有课程
	querySearchCourse();
})

//分页
const handleCurrentChange = ( val )=>{
	//页面的赋值
	queryCoursePrams.pageNum = val;
	//查询对应页的数据
	querySearchCourse();
}


//点击分类
const buildingCondition = ( type , id )=>{

  if (type === 'fcategory') {
    currentId['scategory'].id = '';
    currentId['clevel'].id = '';
    currentId[type].id = id;
    queryCoursePrams.entity.courseLevel = '';
    queryCoursePrams.entity.secondCategory = '';
    queryCoursePrams.entity.firstCategory = id;
    category.categoryId = id;
    getSecondCategorysFn(category);
    querySearchCourse();
    return;
  }
  if( type === 'scategory' ){
    currentId['clevel'].id = '';
    currentId[type].id = id;
    queryCoursePrams.entity.courseLevel = '';
    queryCoursePrams.entity.secondCategory = id;
    querySearchCourse();
    return;
  }
  if( type ==='clevel'){
    currentId[type].id = id;
    queryCoursePrams.entity.courseLevel = id;
    //查询所有课程
    querySearchCourse();
    return;
  }

}


</script>


<style scoped>
.course-main {
  padding: 20px 0;
  width: 100%;
  height: 130px;
  background: #f3f5f9;
}
.search-container{
  width: 1200px;
  margin: 0 auto;
  position: relative;
  height: 100%;
}
.search-item{
  display: flex;
  overflow: hidden;
  cursor: pointer;
  position: absolute;
  height: 45px;
  transition: all 0.5s;
}
.search-item-transition:hover{
  z-index: 777;
  height: auto;
  box-shadow: rgb(95 101 105 / 10%) 0px 12px 20px 0px;
  border-radius: 8px;
  background: rgba(255,255,255);
}
.search-item .title-name {
  width: 100px;
  font-size: 16px;
  font-family: Microsoft YaHei;
  font-weight: bold;
  line-height: 25px;
  text-align: justify;
  color: #333333;
  padding: 10px;
  opacity: 1;
}
.search-item .title-name:after {
  content: '.';
  width: 100%;
  display: inline-block;
  overflow: hidden;
  height: 0;
}

.search-item .all-items{
  width: calc(100% - 120px);
  min-height: 25px;
  display: flex;
  flex-wrap: wrap;
}
.title .all-list {
  width: 40px;
  height: 25px;
  line-height: 25px;
  border-radius: 4px;
  padding: 0 10px;
  align-items: center;
  text-align: center;
}

.title .all {
  opacity: 1;
  color: #2c80ff;
}

.title .item {
  height: 25px;
  line-height: 25px;
  margin: 0 15px;
  font-size: 16px;
  font-family: Microsoft YaHei;
  font-weight: 400;
  line-height: 21px;
  opacity: 1;
}

.title .item .active {
  color: #2c80ff;
}

.category-poniter {
  height: 25px;
  line-height: 25px;
  margin: 10px 5px;
  cursor: pointer;
  border: none;
  background: rgba(44, 128, 255, 0.1);
  color: #2c80ff;
}
.category-poniter-item {
  height: 25px;
  line-height: 25px;
  margin: 10px 5px;
  cursor: pointer;
  border: none;
  background: none;
  color: rgba(81, 87, 89, 1);
}

.main-container {
  width: 1200px;
  margin: 0 auto;
}

.container-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 12px;
}

.all {
  display: flex;
  padding-top: 20px;
  font-size: 16px;
  color: #515759;
}

.all .item:first-child {
  margin-right: 20px;
}

.all .item {
  margin: 0 10px;
  cursor: pointer;
}

.right {
  display: flex;
  padding-top: 20px;
  font-size: 16px;
  color: #515759;
}

.right .right-item {
  margin-left: 10px;
}

.right .right-items {
  margin-right: 0px;
}

.arrow {
  position: relative;
}

.arrow i:first-child {
  position: absolute;
  top: -1px;
}

.arrow i:last-child {
  position: absolute;
  top: 7px;
}

.check {
  width: 15px;
  height: 15px;
  cursor: pointer;
}

.up {
  position: absolute;
  top: 5px;
  left: 2px;
}

.down {
  position: absolute;
  top: 15px;
  left: 2px;
  transform: rotate(180deg);
  -ms-transform: rotate(180deg); /* IE 9 */
  -moz-transform: rotate(180deg); /* Firefox */
  -webkit-transform: rotate(180deg); /* Safari 和 Chrome */
  -o-transform: rotate(180deg); /* Opera */
}
.newCourseContent {
  width: 1200px;
  margin: 30px auto 0px auto;
}

.newCourseContent .courseUl {
  display: flex;
  flex-wrap: wrap;
}

.courseItem{
	width: 285px;
    height: 280px;
    margin: 0 20px 20px 0;
    transition: margin-top 0.2s;
}
.courseItem:hover{
    margin-top: -10px;
    cursor: pointer;
}
.courseItem:nth-child(4n+0){
    margin-right: 0 !important;
}
.courseInfo{
	position: relative;
    width: 100%;
    height: 270px;
    background: #ffffff;
    box-shadow: 1px 1px 10px rgb(27 39 94 / 40%);
    opacity: 1;
    border-bottom-left-radius: 6px;
    border-bottom-right-radius: 6px;
    overflow: hidden;
    text-decoration: none;
}
.courseBg{
	position: relative;
    width: 100%;
    height: 160px;
}
.courseBg img{
	width: 100%;
    height: 100%;
}
.courseName{
    margin: 10px;
    font-weight: bold;
    font-size: 14px;
    color: #333333;
    display: -webkit-box;
    overflow: hidden;
}
.courseDegree{
    margin-left: 10px;
    font-size: 12px;
    color: #808080;
}
.coursePrice {
    display: flex;
    justify-content: space-around;
    align-items: center;
    width: 130px;
    font-size: 14px;
    margin-top: 15px;
    padding: 0 5px;
}
.coursePricePri{
    width: 75px;
    font-size: 14px;
    margin-top: 18px;
    padding: 0 13px;
    color: rgba(255, 114, 127, 1);
    font-weight: 700;
}
.coursePriceZero{
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 75px;
    font-size: 14px;
    margin-top: 15px;
    padding: 0 10px;
    color: rgba(53, 134, 255, 1);
}
.courseMemberbg {
    position: relative;
    width: 80px;
    height: 20px;
    color: #ffffff;
    background: linear-gradient(90deg, #ff928e 0%, #fe7062 99%);
    border-radius: 24px 0px 24px 0px;
}
.courseMember {
    position: absolute;
    line-height: 20px;
    left: 13px;
    font-weight: 700;
}
.price {
    line-height: 25px;
    left: 100px;
    color: #ff727f;
    font-weight: 700;
}
.pages{
	display: flex;
	align-items: center;
	justify-content: center;
	padding:20px 0; 
}
</style>