遇到問題：需要定時刷新獲取新的數據進行展示
解決方法：setInterval()定時刷新
備註：在vue項目中，我們該將刷新放在生命週期的mounted階段。
代碼：
//定時刷新
mounted() {
if(this.timer){
clearInterval(this.timer)
}else{
this.timer=setInterval(()=>{
//獲取數據
this.loadData()
},6000)
}
},
//組件銷燬時清除
destroyed(){
clearInterval(this.timer)
},
首先看一下生命週期：
看一段代碼：（可粘貼複製直接運行）
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<script type="text/javascript" src="https://cdn.jsdelivr.net/vue/2.1.3/vue.js"></script>
</head>
<body>
<div id="app">
<p>{{ message }}</p>
</div>
<script type="text/javascript">
new Vue({
el: '#app',
data: {
message: "weiqiujuan"
},
beforeCreate: function () {
console.group('beforeCreate 創建前狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el); //undefined
console.log("%c%s", "color:red", "data : " + this.$data); //undefined
console.log("%c%s", "color:red", "message: " + this.message)
},
created: function () {
console.group('created 創建完畢狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el); //undefined
console.log("%c%s", "color:red", "data : " + this.$data); //已被初始化
console.log("%c%s", "color:red", "message: " + this.message); //已被初始化
},
beforeMount: function () {
console.group('beforeMount 掛載前狀態===============》');
console.log("%c%s", "color:red", "el : " + (this.$el)); //已被初始化
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data); //已被初始化
console.log("%c%s", "color:red", "message: " + this.message); //已被初始化
},
mounted: function () {
console.group('mounted 掛載結束狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el); //已被初始化
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data); //已被初始化
console.log("%c%s", "color:red", "message: " + this.message); //已被初始化
},
beforeUpdate: function () {
console.group('beforeUpdate 更新前狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data);
console.log("%c%s", "color:red", "message: " + this.message);
},
updated: function () {
console.group('updated 更新完成狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data);
console.log("%c%s", "color:red", "message: " + this.message);
},
beforeDestroy: function () {
console.group('beforeDestroy 銷燬前狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data);
console.log("%c%s", "color:red", "message: " + this.message);
},
destroyed: function () {
console.group('destroyed 銷燬完成狀態===============》');
console.log("%c%s", "color:red", "el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data);
console.log("%c%s", "color:red", "message: " + this.message)
}
})
</script>
</body>
</html>
結果：
是不是很清楚呀！
所以，我們的setInterval是放在mounted上的。
注： 使用setInterval時this指向的問題，如果我們直接使用this.timer=setInterval(function(){//要觸發的函數})報錯的，因爲this指向的是window，但是我們要觸發的函數是掛載在vm實例上的，所以需要使用箭頭函數。