methods和conputed区别
1.computed是属性调用，而methods是函数调用
2.computed带有缓存功能，而methods不是
例子（购物车总价）
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Vue.js computed练习——计算购物车总价</title>
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<style type="text/css">
.container {
display: flex;
flex-direction: column;
width: 95%;
margin: 0 auto;
}
.item {
display: flex;
border: 1px solid #eee;
border-radius: 10px;
width: 95%;
height: 80px;
margin-bottom: 8px;
/* 垂直方向居中 */
align-items: center;
/* 水平方向居中 */
/* justify-content: center; */
padding-left: 10px;
padding-right: 10px;
}
.item-id {
flex: 1 1 10%;
}
.item-name {
flex: 1 1 20%;
}
.item-img {
flex: 1 1 20%
}
.item-img img {
width: 100%;
height: 100%;
}
.item-price {
flex: 1 1 15%;
}
.item-count {
flex: 1 1 35%;
}
.goods-count {
width: 20px;
text-align: center;
}
.settlement {
display: flex;
justify-content: space-between;
align-items: center;
}
.btn {
width: 100px;
height: 40px;
background-color: #FF5000;
border-radius: 10px;
border: none;
outline: none;
color: #FFF;
font-size: 16px;
}
</style>
</head>
<body>
<div id="app">
<div class="container">
<div class="item" v-for="goods in goodsList">
<div class="item-id">
{{goods.id}}
</div>
<div class="item-name">
{{goods.name}}
</div>
<div class="item-img">
<img :src="goods.imgUrl">
</div>
<div class="item-price">
{{goods.price}}
</div>
<div class="item-count">
<button type="button" @click="goods.count-=1" :disabled="goods.count === 0">-</button>
<input type="text" class="goods-count" v-model="goods.count" />
<button type="button" @click="goods.count+=1">+</button>
</div>
</div>
<hr>
<div class="settlement">
<h3>总价：￥{{totalPrice}}</h3>
<button type="button" class="btn" @click="settlement()">结算</button>
</div>
<div class="result" v-if="show">
你购买了{{settlement}}件商品，需要支付总价为：{{totalPrice}}元
</div>
</div>
</div>
<script type="text/javascript">
var app = new Vue({
el: '#app',
data: {
goodsList: [{
id: 1,
name: 'iPhone 8',
imgUrl: 'img/iPhone8.jpg',
price: 6000,
count: 1
},
{
id: 2,
name: 'iPhone X',
imgUrl: 'img/iPhoneX.jpg',
price: 7000,
count: 1
},
{
id: 3,
name: 'iPhone xs Max',
imgUrl: 'img/iPhoneXS.jpg',
price: 8000,
count: 1
}
],
show: false
},
methods: {},
computed: {
totalPrice: function() {
var totalPrice = 0;
var len = this.goodsList.length;
for (var i = 0; i < len; i++) {
totalPrice += this.goodsList[i].price * this.goodsList[i].count;
}
return totalPrice;
},
settlement: function() {
this.show = true;
var totalCount = 0;
var len = this.goodsList.length;
for (var i = 0; i < len; i++) {
totalCount += this.goodsList[i].count;
}
return totalCount;
}
}
})
</script>
</body>
</html>
Snipaste_2019-03-15_16-26-46.png
