刚学习vue不久，今天试着用vue做了一个简单的loading进度条，对于vue的生命周期和钩子函数又有了新的理解，下面分享给大家，绝对入门级。
一、进度条原理
这个就很简单了，也是我们经常可以用到的，这里只做一个最简单的，页面刷新自动加载进度条。主要是让进度条的width不断增加至100%就可以啦~好了，进入正题。
二、jquery实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://cdn.bootcss.com/foundation/5.5.3/css/foundation.min.css" rel="external nofollow" rel="external nofollow" >
<link rel="stylesheet" href="http://static.runoob.com/assets/foundation-icons/foundation-icons.css" rel="external nofollow" rel="external nofollow" >
<title>jq进度条</title>
</head>
<body>
<div id="app">
<div class="progress round alert">
<span class="meter" style="width:0%">0%</span>
</div>
</div>
<script src="https://cdn.bootcss.com/vue/2.4.4/vue.min.js"></script>
<script src="https://cdn.bootcss.com/jquery/2.1.1/jquery.min.js "></script>
<script src="https://cdn.bootcss.com/foundation/5.5.3/js/foundation.min.js "></script>
<script>
$(function () {
var html = $('.meter');
var htmlW = $('.meter').val();
var styleW = parseInt($('.meter').css('width'));
var clearInt = setInterval(function () {
styleW++;
var styleWW = styleW + '%';
html.css('width', styleWW);
html.html(styleWW);
if (styleW == 100) {
clearInterval(clearInt);
}
}, 20)
})
</script>
</body>
</html>
三、vue实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>vue进度条</title>
<link rel="stylesheet" href="https://cdn.bootcss.com/foundation/5.5.3/css/foundation.min.css" rel="external nofollow" rel="external nofollow" >
<link rel="stylesheet" href="http://static.runoob.com/assets/foundation-icons/foundation-icons.css" rel="external nofollow" rel="external nofollow" >
<style>
.bar{
color: #fff;
text-align: center;
}
</style>
</head>
<body>
<div id="app">
<div class="progress alert round">
<span class="meter bar" :style="{width:proBar+'%',}" >{{proBar}}</span>
</div>
</div>
<script src="https://cdn.bootcss.com/vue/2.4.4/vue.min.js"></script>
<script src="https://cdn.bootcss.com/jquery/2.1.1/jquery.min.js "></script>
<script src="https://cdn.bootcss.com/foundation/5.5.3/js/foundation.min.js "></script>
<script>
var app = new Vue({
el: '#app',
data: {
proBar: 0,
},
created(){
this.change();
},
methods: {
change: function() {
var clearInt = setInterval(function() {
app.proBar++;
console.log(app.prpBar);
if (app.proBar == 100) {
clearInterval(clearInt);
}
}, 20)
}
}
})
</script>
</body>
</html>
对比两段代码显然vue要方便许多，因为是双向绑定，不用来回操作dom，就很简单省心啦。
注意问题：刚开始没有实现loading效果，主要是因为用了mounted钩子函数来调用change方法（还是对生命周期理解的不到位）。实现loading效果我们需要在页面加载时自动调用change方法，所以我们应该在数据全部初始化前就执行这一操作。mounted时期已经全部完成初始化，所以便不会成功。
