1.Vue定时任务setInterval
使用时，只需要加上 setInterval 即可，如下：
mounted() {
this.getElevatorList();
setInterval(this.getElevatorList, 15000);
}
在mounted（）函数里边使用setInterval(), getElevatorList()这个方法在methods里边写，在mounted钩子函数里边调用就可以，刚开始先调用一遍，加载。然后使用setInterval(),第一个参数，调用方法的时候，不加括号，第二个参数是时间。
2.实例：
<template lang="html">
<div v-loading="isLoading">
<div class="div-a">
<el-row>
<el-col :span="12" v-for="(item, index) in dataList" :key="index">
<div class="image" :style="'height:' + itemBlockHeight + 'px'">
<div class="item-tag">
<span><b>创建时间：</b>{{item.createTime | TimeFormat}}</span>
<span><b>上传用户：</b>{{item.userName}}</span>
</div>
<div class="video-container" v-if="item.type == 2">
<video controls="controls" autoplay="autoplay" muted>
<source :src="item.fileUrl" type="video/ogg">
<source :src="item.fileUrl" type="video/mp4">
Your browser does not support the video tag.
</video>
</div>
<div class="image-container" v-else>
<img :src="item.fileUrl" @click="handleImagePreview(item.imgMap.colour)">
</div>
</div>
</el-col>
</el-row>
<div class="alert-container" v-if="showAlertContainer">
<el-button v-if="contentType == 'history' " size="small" class="history-btn" type="warning" @click="handleSwitch('current')">当前报警</el-button>
<el-button v-else size="small" class="history-btn" type="warning" @click="handleSwitch('history')">历史报警</el-button>
<el-button :loading="isClosing" size="small" class="history-btn second" type="danger" @click="handleCloseAlert()">关闭当前报警</el-button>
<img class="close-btn" src="../../../assets/close.png" @click="closeAlertModal()" />
<div class="alert-content" v-if="contentType == 'current' ">
<div class="mobile">
<div class="item-tag">
<span><b>区域：</b>{{WarningCondition.areaInfoName}}</span>
<span><b>报警信息名称：</b>{{WarningCondition.name}}</span>
<span><b>报警时间：</b>{{WarningCondition.createTime | TimeFormat}}</span>
<span>
<b>报警触发条件：</b> {{WarningCondition.type==1?'人员':'车辆'}} 大于 {{ WarningCondition.threshold }}
</span>
</div>
<div class="video-container" v-if="alertInfo.type == 2">
<video controls="controls" autoplay="autoplay" muted>
<source :src="alertInfo.fileUrl" type="video/ogg">
<source :src="alertInfo.fileUrl" type="video/mp4">
Your browser does not support the video tag.
</video>
</div>
<div class="image-container" v-else>
<img :src="alertInfo.fileUrl">
</div>
</div>
</div>
<div class="alert-content" v-else>
<el-row style="padding: 30px 0;">
<el-col :span="20" :offset="2">
<el-table
:data="alertHistoryData"
border
v-loading.body="isTableLoading"
style="width: 100%">
<el-table-column
label="报警名称">
<template scope="scope">
<span style="margin-left: 10px">{{ scope.row.warningCondition.name }}</span>
</template>
</el-table-column>
<el-table-column
label="报警位置">
<template scope="scope">
<span style="margin-left: 10px">{{ scope.row.address }}</span>
</template>
</el-table-column>
<el-table-column
label="报警区域">
<template scope="scope">
<span style="margin-left: 10px">{{ scope.row.areaInfoName }}</span>
</template>
</el-table-column>
<el-table-column
label="报警级别">
<template scope="scope">
<span style="margin-left: 10px">{{ scope.row.hazardLevel }} 级</span>
</template>
</el-table-column>
<el-table-column
label="报警类型">
<template scope="scope">
<el-tag v-if=" scope.row.warningCondition.type == 1 " type="success">人员</el-tag>
<el-tag v-if=" scope.row.warningCondition.type == 2 " type="primary">车辆</el-tag>
</template>
</el-table-column>
<el-table-column
label="报警数值">
<template scope="scope">
<el-tag type="warning">{{scope.row.warningCondition.threshold}}</el-tag>
</template>
</el-table-column>
<el-table-column
label="创建时间">
<template scope="scope">
<span style="margin-left: 10px">{{ scope.row.createTime | TimeFormat }}</span>
</template>
</el-table-column>
</el-table>
</el-col>
</el-row>
<el-row>
<el-col :span="24" style="text-align:center">
<el-pagination
style="text-align:center;"
@size-change="handleSizeChange"
@current-change="handleCurrentChange"
:current-page="alertHistoryPageNum"
:page-sizes="[5, 10, 20, 50]"
:page-size="alertHistoryPageSize"
layout="total, sizes, prev, pager, next, jumper"
:total="alertHistoryTotalCount">
</el-pagination>
</el-col>
</el-row>
</div>
</div>
</div>
<div class="div-b">
<div class="wrapper" >
<!--<div class="btn-ground">
<a href="javascript:;">圆形</a>
<a href="javascript:;">正方形</a>
<a href="javascript:;">点</a>
<a href="javascript:;">直线</a>
</div>-->
<div class="div1"></div>
</div>
</div>
</div>
</template>
<script>
import { mapActions } from 'vuex'
import eventHub from '@/eventHub'
import VideoBox from '@/components/common/VideoBox'
import Promise from 'bluebird'
import _ from 'lodash'
/*鼠标画图*/
//声明变量
var wId = "w";
var index = 0;
var startX = 0,startY = 0;
var flag = false;
var retcLeft = "0px", retcTop = "0px", retcHeight = "0px", retcWidth = "0px";
var $ = function(id){
return document.getElementById(id);
}
export default {
data(){
let height = document.body.clientHeight;
let itemBlockHeight = height / 2;
return {
isStoping:false,
dataList: [],
pageSize: 4,
pageNum: 1,
totalCount:0,
isLoading: false,
carouselTime: 10,
carouselIndex: null,
itemBlockHeight: itemBlockHeight,
showAlertContainer:false,
checkAlertCarousel:null,
alertInfo:{},
isClosing:false,
alertHistoryData: [],
contentType:'current',
alertHistoryPageSize: 10,
alertHistoryPageNum: 1,
alertHistoryTotalCount:0,
isTableLoading:false,
WarningCondition:{}
}
},
components:{
VideoBox
},
mounted(){
this.isLoading = true;
Promise.all([
this.getResource({
pageSize: this.pageSize,
pageNum: this.pageNum
}),
this.getAlertHistory({
type:4,
pageSize:this.alertHistoryPageSize,
pageNum:this.alertHistoryPageNum
})
])
.spread((result, alertHistory)=>{
this.alertHistoryData = alertHistory.resultData;
this.alertHistoryTotalCount = alertHistory.totalCount;
this.totalCount = result.totalCount;
this.dataList = result.resultData;
this.isLoading = false;
if(result.resultData.length == 4){
this.carousel();
}
},()=>{
this.isLoading = false;
this.$message.error('数据加载失败！');
});
this.checkAlertCarousel = setInterval(()=>{
// 1 摄像头； 2:无人机； 3卫星； 4移动端
this.checkAlertStatus({deviceType:4})
.then((result)=>{
if(result.data){
this.alertInfo = result.data;
this.WarningCondition = result.WarningCondition;
this.showAlertContainer = true;
}
if(result.warningDeviceType){
this.isStoping = true;
clearInterval(this.carouselIndex)
}else{
if(this.isStoping) {
this.carousel();
}
this.isStoping = false;
}
},()=>{})
},5000);
/*鼠标画图*/
const vm = this;
let dom = document.querySelector(".div1");
//鼠标按下时发生的事件
document.onmousedown = function(e){
flag = true;
try{
var evt = window.event || e;
var scrollTop = (document.body.scrollTop || document.documentElement.scrollTop);//上边 设置或获取位于对象最顶端和窗口中可见内容的最顶端之间的距离
var scrollLeft = document.body.scrollLeft || document.documentElement.scrollLeft;//左边 获取对象相对于版面或由 offsetParent 属性指定的父坐标的计算左侧位置
startX = evt.clientX + scrollLeft;
startY = evt.clientY + scrollTop;
index++;
//开始创建div,设置div的各种属性
var div = document.createElement("div");
div.id = wId + index;
div.className = "div";
div.style.marginLeft = startX + "px";
div.style.marginTop = (evt.clientY-120) + "px";
dom.appendChild(div);
}catch(e){
}
}
//鼠标放开事件
document.onmouseup = function(){
try{
dom.removeChild($(wId + index));
var div = document.createElement("div");
div.className = "retc";
div.style.marginLeft = retcLeft;
div.style.marginTop = (parseInt(retcTop)-120)+"px";
div.style.width = retcWidth;
div.style.height = retcHeight;
dom.appendChild(div);
var w = parseInt(retcWidth.substring(0,retcWidth.length-2));
var h = parseInt(retcHeight.substring(0,retcHeight.length-2));
var x1 = parseInt(retcLeft.substring(0,retcLeft.length-2));
var y1 = parseInt(retcTop.substring(0,retcTop.length-2));
var x2 = x1+w;
var y3 = y1+h;
console.log("顶点("+x1+","+y1+")");
console.log("宽"+w);
console.log("高"+h);
console.log("p2("+x2+","+y1+")");
console.log("p3("+x1+","+y3+")");
console.log("p4("+x2+","+y3+")");
}catch(e){
//alert(e);
}
flag = false;
}
//鼠标移动时
document.onmousemove = function(e){
if(flag){
try{
var evt = window.event || e;
var scrollTop = document.body.scrollTop || document.documentElement.scrollTop;
var scrollLeft = document.body.scrollLeft || document.documentElement.scrollLeft;
retcLeft = (startX - evt.clientX - scrollLeft > 0 ? evt.clientX + scrollLeft : startX) + "px";
retcTop = (startY - evt.clientY - scrollTop > 0 ? (evt.clientY + scrollTo) : startY) + "px";
retcHeight = Math.abs(startY - evt.clientY - scrollTop) + "px";
retcWidth = Math.abs(startX - evt.clientX - scrollLeft) + "px";
$(wId + index).style.marginLeft = retcLeft;
$(wId + index).style.marginTop = (parseInt(retcTop)-120)+"px";
$(wId + index).style.width = retcWidth;
$(wId + index).style.height = retcHeight;
}catch(e){
//alert(e);
}
}
}
},
beforeRouteLeave(to, from, next) {
clearInterval(this.carouselIndex)
clearInterval(this.checkAlertCarousel)
next()
},
methods:{
...mapActions([
'closeAlert',
'getResource',
'getAlertHistory',
'checkAlertStatus'
]),
carousel(){
this.carouselIndex = setInterval(this.loadMore, 1000 * this.carouselTime);
},
handleSwitch(type){
this.contentType = type;
},
handleCloseAlert(){
this.isClosing = true;
this.closeAlert()
.then(()=>{
this.isClosing = false;
this.showAlertContainer = false;
eventHub.$emit('show-videobox');
this.$message({
message: '报警关闭成功',
type: 'success'
});
this.alertInfo = {};
},()=>{
this.isClosing = false;
this.$message({
message: '报警关闭失败',
type: 'error'
});
})
},
closeAlertModal(){
this.closeAlert();
this.showAlertContainer = false;
},
loadMore(){
this.pageNum = this.pageNum + 1;
this.getResource({
pageSize: this.pageSize,
pageNum: this.pageNum
})
.then((result) => {
if(result.resultData.length > 0) this.dataList = _.concat(result.resultData, _.slice(this.dataList, 0, 4 - result.resultData.length));
if(this.pageSize * this.pageNum >= this.totalCount) this.pageNum = 0;
}, () => {
this.$message.error('数据加载失败！');
})
},
handleSizeChange(pageSize){
this.alertHistoryPageSize = pageSize;
this.alertHistoryPageNum = 1;
this.isTableLoading = true;
this.getAlertHistory({
type:2,
pageSize:this.alertHistoryPageSize,
pageNum:this.alertHistoryPageNum
})
.then((result) => {
this.isTableLoading = false;
this.alertHistoryTotalCount = result.totalCount;
this.alertHistoryData = result.resultData;
}, () => {
this.isTableLoading = false;
this.$message.error('列表加载失败！');
})
},
handleCurrentChange(pageNum){
this.alertHistoryPageNum = pageNum;
this.isTableLoading = true;
this.getAlertHistory({
type:2,
pageSize:this.alertHistoryPageSize,
pageNum:this.alertHistoryPageNum
})
.then((result) => {
this.isTableLoading = false;
this.alertHistoryTotalCount = result.totalCount;
this.alertHistoryData = result.resultData;
}, () => {
this.isTableLoading = false;
this.$message.error('列表加载失败！');
})
}
}
}
</script>
<style lang="less" scoped>
.image{
height:100%;
overflow:hidden;
position:relative;
overflow:hidden;
padding-top:30px;
box-sizing:border-box;
.item-tag{
display:flex;
padding:0 10px;
justify-content:space-between;
align-items:center;
color:#ffffff;
position:absolute;
left:0;
right:0;
top:0;
height:30px;
background-color:rgba(0,0,0,0.5);
}
.video-container{
position:absolute;
left:0;
right:0;
top:30px;
bottom:0;
video{
width: 100%;
height:100%;
// background-color: #000;
}
}
.image-container{
position:absolute;
left:0;
right:0;
top: 30px;
bottom:0;
text-align:center;
img{
width: 100%;
height: 100%;
}
}
}
.div-a{ position:absolute; left:0px; width:100%; height:100%;}
.div-b{ position:absolute; left:0px; width:100%; height:100%;}
/* body,h1,h2,h3,h4,h5,h6,hr,p,blockquote,dl,dt,dd,ul,ol,li,pre,form,fieldset,legend,button,input,textarea,th,td{margin:0;padding:0} */
/* html{color:#000;overflow-y:scoll;overflow:-moz-scrollbars-vertical} */
</style>
<style>
.wrapper{position: relative;width: 100%;height: 90%;margin-top: 60px}
.btn-ground{position: absolute;top: 0;left: 0;right: 0;width: 100%;height:50px;padding-left: 20px;line-height: 50px;text-align: left;z-index:99;}
.btn-ground a{display: inline-block;margin-left: 10px;height: 30px;border-radius: 10px;line-height: 30px;
text-align: center;padding: 0 0px;color:white;background-color:#049ff1;text-decoration: none;}
.div{position:absolute; border:1px dashed blue;left:0px; top:0; overflow:hidden;z-index: 9;margin: 0px}
.retc{position:absolute; border:2px solid darkred; overflow:hidden;cursor: crosshair;}
</style>
3.vue 定时器的问题
在项目中，我们经常会使用到定时器setInterval()，可是很多时候我们会发现，即使我退出当前页面，定时器依然在工作，非常消耗内存，所以我们要进行手动清理：
将定时器保存在变量中，退出页面时清除变量
1.定义空的变量
data: function (){
return {
timer: null
}
}
2.定义定时器
methods: {
setTimer: function () {
this.timer = setInterval( () => {
.....
}, 1000)
}
}
3.进入和退出时清除定时器
mounted() {
clearInterval(this.timer)
},
distroyed: function () {
clearInterval(this.timer)
}
4.Vue中使用定时器setInterval和setTimeout
参考链接：https://www.cnblogs.com/jin-zhe/p/10001236.html
js中定时器有两种，一个是循环执行setInterval，另一个是定时执行setTimeout
一、循环执行（setInterval）
顾名思义，循环执行就是设置一个时间间隔，每过一段时间都会执行一次这个方法,直到这个定时器被销毁掉
用法是setInterval（“方法名或方法”，“延时”）， 第一个参数为方法名或者方法，注意为方法名的时候不要加括号,第二个参数为时间间隔
<template>
<section>
<h1>hello world~</h1>
</section>
</template>
<script>
export default {
data() {
return {
timer: '',
value: 0
};
},
methods: {
get() {
this.value ++;
console.log(this.value);
}
},
mounted() {
this.timer = setInterval(this.get, 1000);
},
beforeDestroy() {
clearInterval(this.timer);
}
};
</script>
上面的例子就是页面初始化的时候创建了一个定时器setInterval，时间间隔为1秒，每一秒都会调用一次函数get，从而使value的值加一。
二、定时执行 （setTimeout）
定时执行setTimeout是设置一个时间，等待时间到达的时候只执行一次，但是执行完以后定时器还在，只是没有运行
用法是setTimeout(“方法名或方法”, “延时”); 第一个参数为方法名或者方法，注意为方法名的时候不要加括号,第二个参数为时间间隔
<template>
<section>
<h1>hello world~</h1>
</section>
</template>
<script>
export default {
data() {
return {
timer: '',
value: 0
};
},
methods: {
get() {
this.value ++;
console.log(this.value);
}
},
mounted() {
this.timer = setTimeout(this.get, 1000);
},
beforeDestroy() {
clearTimeout(this.timer);
}
};
</script>
上面是页面初始化时候创建一个定时器setTimeout，只在1秒后执行一次方法。
定时器需要在页面销毁的时候清除掉，不然会一直存在！！！