有經常看直播的小伙伴們應該都有發(fā)現(xiàn)，我們在打開一個直播間之后評論會一直不斷的滾動一會就跳過我們剛看到的那部分，我們就需要自己手動往上翻才可以找到我們要的剛才的評論，那么今天我們就來說說有關于：“在html5中怎么設置直播間評論滾動？”這個問題的相關內容吧！
首先我們來看看效果圖：
直播間評論滾動效果，下劃查看歷史消息并停止?jié)L動，如有新消息會出現(xiàn)新消息提醒，點擊滾動到底部。
2.具體代碼
<template>
<div class="comment">
<div class="comment-wrap" ref="wrapper">
<ul class="list" ref="list">
<li v-for="item in list" :key="item.id">
<span class="name">{{item.name}}：</span>
<span class="content">{{item.content}}</span>
</li>
</ul>
</div>
<div class="rest-nums" v-show="restComment" @click="scrollBottom">{{restComment}}條新消息</div>
</div>
</template>
<script>
import smoothscroll from 'smoothscroll-polyfill';
import { debounce, isScrollBottom } from '../utils/utils';
smoothscroll.polyfill(); // 移動端scrollTo behavior: "smooth"動畫失效的polyfill
export default {
data() {
return {
list: [],
restComment: 0,
restNums: 0,
wrapperDom: null,
listDom: null,
wrapperHeight: 0
};
},
mounted() {
this.initDom();
// ajax...
const data = new Array(20).fill('');
this.queue(data);
setTimeout(() => {
const list = new Array(10).fill('');
this.queue(list);
}, 30000);
},
methods: {
initDom() {
this.wrapperDom = this.$refs.wrapper;
this.listDom = this.$refs.list;
this.wrapperHeight = this.wrapperDom.offsetHeight;
},
addTimeOut(opt) {
return new Promise((resolve, reject) => {
setTimeout(() => {
this.addComment(opt);
resolve()
}, 500);
});
},
// 隊列添加消息
async queue(data) {
for (let i = 0; i < data.length; i++) {
const opt = {
name: i + "-用戶名",
content: i + "-評論內容",
id: Date.now()
}
await this.addTimeOut(opt);
}
},
addScroll() {
debounce(this.listScroll, 200);
this.isBindScrolled = true;
},
listScroll() {
const ele = this.wrapperDom;
const isBottom = isScrollBottom(ele, ele.clientHeight);
if (isBottom) {
this.restNums = 0;
this.restComment = 0;
}
},
// 添加評論 如果超過150條就將前50條刪除
addComment(data) {
if (this.list.length >= 150) {
this.list.splice(0, 50);
}
this.list.push(data);
this.$nextTick(() => {
this.renderComment();
});
},
// 渲染評論
renderComment() {
const listHight = this.listDom.offsetHeight;
const diff = listHight - this.wrapperHeight; // 列表高度與容器高度差值
const top = this.wrapperDom.scrollTop; // 列表滾動高度
if (diff - top < 50) {
if (diff > 0) {
if (this.isBindScrolled) {
this.isBindScrolled = false;
this.wrapperDom.removeEventListener("scroll", this.addScroll);
}
this.wrapperDom.scrollTo({
top: diff + 10,
left: 0,
behavior: "smooth"
});
this.restNums = 0;
}
} else {
++this.restNums;
if (!this.isBindScrolled) {
this.isBindScrolled = true;
this.wrapperDom.addEventListener("scroll", this.addScroll);
}
}
this.restComment = this.restNums >= 99 ? "99+" : this.restNums;
},
// 滾動到底部
scrollBottom() {
this.restNums = 0; // 清除剩余消息
this.restComment = this.restNums;
this.wrapperDom.scrollTo({
top: this.listDom.offsetHeight,
left: 0,
behavior: "smooth"
});
}
}
};
</script> <style scoped>
*{
padding: 0;
margin: 0;
}
.comment{
width: 70%;
height: 350px;
position: relative;
margin: 100px 0 0 20px;
}
.comment-wrap{
height: 350px;
overflow-y: scroll;
-webkit-overflow-scrolling:touch;
}
.comment-wrap li{
text-align: left;
line-height: 30px;
padding-left: 10px;
background: rgba(0, 0, 0, 0.3);
margin-top: 5px;
border-radius: 15px;
color: #fff;
}
.rest-nums{
position: absolute;
height: 24px;
line-height: 24px;
color: #f00;
border-radius: 15px;
padding: 0 15px;
bottom: 10px;
background: #fff;
font-size: 14px;
left: 10px;
}
</style>用的的兩個工具函數(shù)：
/**
* @desc 函數(shù)防抖
* @param {需要防抖的函數(shù)} func
* @param {延遲時間} wait
*/
export function debounce(func, wait = 500) {
// 緩存一個定時器id
let timer = 0;
// 這里返回的函數(shù)是每次用戶實際調用的防抖函數(shù)
// 如果已經設定過定時器了就清空上一次的定時器
// 開始一個新的定時器，延遲執(zhí)行用戶傳入的方法
return function (...args) {
if (timer) clearTimeout(timer)
timer = setTimeout(() => {
func.apply(this, args)
}, wait)
}
}
/**
* @desc 是否滾到到容器底部
* @param {滾動容器} ele
* @param {容器高度} wrapHeight
*/
export function isScrollBottom(ele, wrapHeight, threshold = 30) {
const h1 = ele.scrollHeight - ele.scrollTop;
const h2 = wrapHeight + threshold;
const isBottom = h1 <= h2;
return isBottom;
}總結
通過這篇文章的分析想必大家對于：“在html5中怎么設置直播間評論滾動？”這方面的相關內容也有了不少的了解，當然了如果你對于html5這方面的知識內容有感興趣的小伙伴也可以在W3Cschool中進行學習和了解！
