零、前因
我们在日常的开发种，这种页面在项目当中经常会用得到，所以本篇文章会比较注重描述其思路，顺带附上其代码，以便以后在任何代码环境下都能使用上，先介绍一下实现思路：
- 点击左侧类别，右侧会跳转到对应的分类；
- 右侧滚动到顶部区域，左侧自动高亮对应的类别。
要求就这么多，可以先看下效果如何：
一、搭建结构
重点：使用uniapp的scroll-view组件，如果是小程序原生开发也是这个组件；其次如果是html开发，就自己实现一个溢出滚动。
废话不多说，上代码：
<template>
<view class="u-wrap">
<view class="u-menu-wrap">
<scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrolltop"
:scroll-into-view="itemid">
<view v-for="(item,index) in tabbar" :key="index" class="u-tab-item" :class="[current == index ? 'u-tab-item-active' : '']"
@tap.stop="swichmenu(index)">
<text class="u-line-1">{{item.name}}</text>
</view>
</scroll-view>
<scroll-view :scroll-top="scrollrighttop" scroll-y scroll-with-animation class="right-box" @scroll="rightscroll">
<view class="page-view">
<view class="class-item" :id="'item' + index" v-for="(item , index) in tabbar" :key="index">
<view class="item-title">
<text>{{item.name}}</text>
</view>
<view class="item-container">
<view class="thumb-box" v-for="(item1, index1) in item.foods" :key="index1" @click="featurec(item1.cat, item1.name)">
<image v-if="item1.icon != ''" class="item-menu-image" :src="item1.icon" mode=""></image>
<view v-else class="item-menu-image row-c" style="background-color: #f4f6f8;"><text style="font-size: 20rpx;color: #d0d0d0;">加载失败</text></view>
<view class="item-menu-name">{{item1.name}}</view>
</view>
</view>
</view>
</view>
</scroll-view>
</view>
</view>
</template>
javascript业务逻辑代码：
data() {
return {
scrolltop: 0, //tab标题的滚动条位置
oldscrolltop: 0, // tab标题的滚动条旧位置
current: 0, // 预设当前项的值
menuheight: 0, // 左边菜单的高度
menuitemheight: 0, // 左边菜单item的高度
itemid: '', // 栏目右边scroll-view用于滚动的id
tabbar: json.parse(uni.getstoragesync('categroy')), // 渲染的数据，放在最后供你们测试
arr: [], // 储存距离顶部高度的数组
scrollrighttop: 0, // 右边栏目scroll-view的滚动条高度
timer: null // 定时器
}
}
css代码：
.u-wrap {
/* #ifdef h5 */
height: calc(100vh - var(--window-top));
/* #endif */
display: flex;
flex-direction: column;
height: 100vh;
}
.u-search-box {
padding: 18rpx 30rpx;
}
.u-menu-wrap {
flex: 1;
display: flex;
overflow: hidden;
}
.u-tab-view {
width: 200rpx;
height: 100%;
}
.u-tab-item {
height: 110rpx;
background: #f6f6f6;
box-sizing: border-box;
display: flex;
align-items: center;
justify-content: center;
font-size: 26rpx;
color: #444;
font-weight: 400;
line-height: 1;
}
.u-tab-item-active {
position: relative;
color: #06a446;
font-size: 30rpx;
font-weight: 500;
background: #d6ffe7;
}
.u-tab-item-active::before {
content: "";
position: absolute;
border-left: 4px solid #06a446;
height: 52rpx;
left: 0;
top: 29rpx;
}
.u-tab-view {
height: 100%;
}
.right-box {
background-color: rgb(250, 250, 250);
}
.page-view {
padding: 16rpx;
}
.class-item {
margin-bottom: 30rpx;
background-color: #fff;
padding: 16rpx;
border-radius: 8rpx;
}
.class-item:last-child {
min-height: 100vh;
}
.item-title {
font-size: 26rpx;
color: $u-main-color;
font-weight: bold;
}
.item-menu-name {
margin-top: 8rpx;
font-weight: normal;
font-size: 24rpx;
color: $u-main-color;
}
.item-container {
display: flex;
flex-wrap: wrap;
}
.thumb-box {
width: 33.333333%;
display: flex;
align-items: center;
justify-content: center;
flex-direction: column;
margin-top: 20rpx;
}
.item-menu-image {
width: 120rpx;
height: 120rpx;
}
二、添加逻辑层业务
分别获取左侧和右侧每一个类别的高度
我们知道，在uniapp里面没有window对象和dom元素，所以如果我们要获取页面上的一些节点信息时，需要通过
uni.createselectorquery()这个api来获取，这里不再赘述。—— 《传送地址》
/**
* 获取一个目标元素的高度
* @elclass 元素的类名
* @dataval 储存高度的对象
*/
methods: {
getelrect(elclass, dataval) {
new promise((resolve, reject) => {
const query = uni.createselectorquery().in(this);
query.select('.' + elclass).fields({
size: true
}, res => {
// 如果节点尚未生成，res值为null，循环调用执行
if (!res) {
settimeout(() => {
this.getelrect(elclass);
}, 10);
return;
}
this[dataval] = res.height;
resolve();
}).exec();
})
}
}
计算右侧每个分类距离顶部的高度并保存
onready() {
this.getmenuitemtop()
},
mehods: {
/**
* 获取右边菜单每个item到顶部的距离
* 储存到 arr 数组里面用于后面滚动判断
*/
getmenuitemtop() {
new promise(resolve => {
let selectorquery = uni.createselectorquery();
selectorquery.selectall('.class-item').boundingclientrect((rects) => {
// 如果节点尚未生成，rects值为[](因为用selectall，所以返回的是数组)，循环调用执行
if(!rects.length) {
settimeout(() => {
this.getmenuitemtop();
}, 10);
return ;
}
rects.foreach((rect) => {
// 视情况而定，这里减去rects[0].top，是因为第一项顶部可能不是贴到导航栏(比如有个搜索框的情况)
// this.arr.push(rect.top - rects[0].top);
this.arr.push(rect.top)
resolve();
})
}).exec()
})
},
}
监听右侧元素滚动时交互的状态
节点布局交叉状态 api 可用于监听两个或多个组件节点在布局位置上的相交状态。这一组api常常可以用于推断某些节点是否可以被用户看见、有多大比例可以被用户看见。这里也不再赘述，不懂的直接阅读文档 —— 《传送地址》
methods: {
/**
* 观测元素相交状态
* 检测右边scroll-view的id为itemxx的元素与right-box的相交状态
* 如果跟.right-box底部相交，就动态设置左边栏目的活动状态
*/
async observer() {
this.tabbar.map((val, index) => {
let observer = uni.createintersectionobserver(this);
observer.relativeto('.right-box', {
top: 0
}).observe('#item' + index, res => {
if (res.intersectionratio > 0) {
let id = res.id.substring(4);
this.leftmenustatus(id);
}
})
})
},
/**
* 设置左边菜单的滚动状态
* @index 传入的 id
*/
async leftmenustatus(index) {
this.current = index;
// 如果为0，意味着尚未初始化
if (this.menuheight == 0 || this.menuitemheight == 0) {
await this.getelrect('menu-scroll-view', 'menuheight');
await this.getelrect('u-tab-item', 'menuitemheight');
}
// 将菜单活动item垂直居中
this.scrolltop = index * this.menuitemheight + this.menuitemheight / 2 - this.menuheight / 2;
}
}
实现左侧菜单点击联动右侧滚动
methods: {
/**
* 点击左边的栏目切换
* @index 传入的 id
*/
async swichmenu(index) {
if(this.arr.length == 0) {
await this.getmenuitemtop();
}
if (index == this.current) return;
this.scrollrighttop = this.oldscrolltop;
this.$nexttick(function(){
this.scrollrighttop = this.arr[index];
this.current = index;
this.leftmenustatus(index);
})
},
}
实现右侧菜单滚动联动左侧高亮
methods: {
/**
* 右边菜单滚动
* 如果不存在height2，意味着数据循环已经到了最后一个，设置左边菜单为最后一项即可
*/
async rightscroll(e) {
this.oldscrolltop = e.detail.scrolltop;
if(this.arr.length == 0) {
await this.getmenuitemtop();
}
if(this.timer) return ;
if(!this.menuheight) {
await this.getelrect('menu-scroll-view', 'menuheight');
}
settimeout(() => { // 节流
this.timer = null;
// scrollheight为右边菜单垂直中点位置
// let scrollheight = e.detail.scrolltop + this.menuheight / 2;
// scrollheight为右边菜单头部位置
let scrollheight = e.detail.scrolltop + 20;
for (let i = 0; i < this.arr.length; i++) {
let height1 = this.arr[i];
let height2 = this.arr[i + 1];
if (!height2 || scrollheight >= height1 && scrollheight < height2) {
this.leftmenustatus(i);
return ;
}
}
}, 10)
}
}
三、最后tabbar数据
[
{
"name":"蔬菜水果",
"foods":[
{
"cat":383,
"name":"蔬菜",
"icon":"http://nq348.com/uploads/category/20220315/1aeed6fa43b54cd68cce0c4883160f91.png",
"key":"蔬菜"
},
{
"cat":384,
"name":"食用菌",
"icon":"http://nq348.com/uploads/category/20220418/09839c618b35b510d50151f9a17793ee.png",
"key":"食用菌"
},
{
"cat":385,
"name":"水果",
"icon":"http://nq348.com/uploads/category/20220418/5294ad2fc7effc9629cbfdb8baf41773.png",
"key":"水果"
}
]
},
{
"name":"畜禽养殖",
"foods":[
{
"cat":388,
"name":"禽类",
"icon":"http://nq348.com/uploads/category/20220418/da31895fc5a9aacf93fea6f27f08afd7.png",
"key":"禽类"
},
{
"cat":389,
"name":"畜类",
"icon":"http://nq348.com/uploads/category/20220418/6352081e3f3b36f9360a933676e9452c.png",
"key":"畜类"
},
{
"cat":391,
"name":"蛋类",
"icon":"http://nq348.com/uploads/category/20220418/d2e7ab4224679c0c796ba3ddd8a68e2f.png",
"key":"蛋类"
},
{
"cat":390,
"name":"水产",
"icon":"http://nq348.com/uploads/category/20220418/52a1f1baa7617ef4d4e1a4b344b2fce7.png",
"key":"水产"
}
]
},
{
"name":"粮油副食",
"foods":[
{
"cat":393,
"name":"米面粮油",
"icon":"http://nq348.com/uploads/category/20220418/1bb32e319ecf5aa352b7fe26fc265004.png",
"key":"米面粮油"
},
{
"cat":394,
"name":"坚果干果",
"icon":"http://nq348.com/uploads/category/20220418/6ded13eae4a3b113b5225ca8b99bbfdd.png",
"key":"坚果干果"
},
{
"cat":395,
"name":"加工食品",
"icon":"http://nq348.com/uploads/category/20220418/1e1c10838799de5834aa77f0f9eb8f40.png",
"key":"加工食品"
},
{
"cat":396,
"name":"茶烟酒",
"icon":"http://nq348.com/uploads/category/20220418/c43cd994e49023c7efdf2b18b1bca30b.png",
"key":"茶烟酒"
}
]
},
{
"name":"花卉苗木",
"foods":[
{
"cat":398,
"name":"鲜花盆景",
"icon":"http://nq348.com/uploads/category/20220418/b21c44045daaa8b8d148981ba9efc2e0.png",
"key":"鲜花盆景"
},
{
"cat":399,
"name":"果树苗",
"icon":"http://nq348.com/uploads/category/20220418/63ee2b902ff0f4d638d8a5ad770f7641.png",
"key":"果树苗"
},
{
"cat":400,
"name":"蔬瓜种子",
"icon":"http://nq348.com/uploads/category/20220418/2df521877616ee44fd01aae0434a5815.png",
"key":"蔬瓜种子"
},
{
"cat":401,
"name":"经济作物",
"icon":"http://nq348.com/uploads/category/20220418/f85be72a98694befd889f30de45a1d64.png",
"key":"经济作物"
}
]
},
{
"name":"中草药材",
"foods":[
{
"cat":403,
"name":"全草类",
"icon":"http://nq348.com/uploads/category/20220418/01812c1a83f5db7eafbf3bdae927f134.png",
"key":"全草类"
},
{
"cat":405,
"name":"根茎皮叶花",
"icon":"http://nq348.com/uploads/category/20220418/dca8dcc814401474d4f19ae7394cc209.png",
"key":"根茎皮叶花"
},
{
"cat":406,
"name":"滋补品类",
"icon":"http://nq348.com/uploads/category/20220418/33b965295811fdd6f5e672e9a3ce34a2.png",
"key":"滋补品类"
},
{
"cat":404,
"name":"果实籽仁类",
"icon":"http://nq348.com/uploads/category/20220418/1dc8c46c66b4625d458a7f45787ecef9.png",
"key":"果实籽仁类"
}
]
},
{
"name":"其他",
"foods":[
{
"cat":434,
"name":"包装",
"icon":"http://nq348.com/uploads/category/20220418/ebdfd326333344825adbe81dbd89e2c9.png",
"key":"包装"
},
{
"cat":435,
"name":"安全溯源",
"icon":"http://nq348.com/uploads/category/20220418/03230c63f066f46005abf5f576df0ed1.png",
"key":"安全溯源"
},
{
"cat":436,
"name":"农用百货",
"icon":"http://nq348.com/uploads/category/20220418/93393f2df3264faba86bb449a0c10a79.png",
"key":"农用百货"
},
{
"cat":437,
"name":"仓储物流",
"icon":"http://nq348.com/uploads/category/20220418/f553505ebabbcb1bf762b288716cf1e7.png",
"key":"仓储物流"
}
]
}
]
总结
到此这篇关于uniapp实现左右联动商品分类页面的文章就介绍到这了,更多相关uniapp左右联动商品分类页面内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持！
