文章目录
- 前言
- 一、指令补充
- 1. 指令修饰符
- 2. v-bind对于样式操作的增强 - class
- 3. 案例 - 京东秒杀 tab 导航高亮
- 4. v-bind对于样式操作的增强 - style
- 5. v-model应用于其他表单元素
- 二、computed计算属性
- 1. 基础语法
- 2. 计算属性 vS method 方法
- 3. 完整写法
- 4. 成绩案例
- 三、watch 侦听器
- 1. 基础语法
- 2. 业务实现
- 3. 完整写法
- 四、综合案例:水果购物车
- 1. 渲染
- 2. 删除和修改数量
- 3. 全选反选
- 4. 统计总价
- 5. 本地持久化
- 总结
前言
为了巩固所学的知识，作者尝试着开始发布一些学习笔记类的博客，方便日后回顾。当然，如果能帮到一些萌新进行新技术的学习那也是极好的。作者菜菜一枚，文章中如果有记录错误，欢迎读者朋友们批评指正。
一、指令补充
1. 指令修饰符
- @keyup.enter
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app">
<h3>@keyup.enter → 监听键盘回车事件</h3>
<input @keyup.enter="fn" v-model="username" type="text">
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
username: ''
},
methods: {
fn (e) {
// if (e.key === 'Enter') {
// console.log('键盘回车的时候触发', this.username)
// }
console.log('键盘回车的时候触发', this.username)
}
}
})
</script>
</body>
</html>
- .trim .number .stop .prevent
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.father {
width: 200px;
height: 200px;
background-color: pink;
margin-top: 20px;
}
.son {
width: 100px;
height: 100px;
background-color: skyblue;
}
</style>
</head>
<body>
<div id="app">
<h3>v-model修饰符 .trim .number</h3>
姓名：<input v-model.trim="username" type="text"><br>
年纪：<input v-model.number="age" type="text"><br>
<h3>@事件名.stop → 阻止冒泡</h3>
<div @click="fatherFn" class="father">
<div @click.stop="sonFn" class="son">儿子</div>
</div>
<h3>@事件名.prevent → 阻止默认行为</h3>
<a @click.prevent href="http://www.baidu.com">阻止默认行为</a>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
username: '',
age: '',
},
methods: {
fatherFn () {
alert('老父亲被点击了')
},
sonFn (e) {
// e.stopPropagation()
alert('儿子被点击了')
}
}
})
</script>
</body>
</html>
2. v-bind对于样式操作的增强 - class
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.box {
width: 200px;
height: 200px;
border: 3px solid #000;
font-size: 30px;
margin-top: 10px;
}
.pink {
background-color: pink;
}
.big {
width: 300px;
height: 300px;
}
</style>
</head>
<body>
<div id="app">
<div class="box" :class="{ pink: true, big: true }">黑马程序员</div>
<div class="box" :class="['pink', 'big']">黑马程序员</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
}
})
</script>
</body>
</html>
3. 案例 - 京东秒杀 tab 导航高亮
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
ul {
display: flex;
border-bottom: 2px solid #e01222;
padding: 0 10px;
}
li {
width: 100px;
height: 50px;
line-height: 50px;
list-style: none;
text-align: center;
}
li a {
display: block;
text-decoration: none;
font-weight: bold;
color: #333333;
}
li a.active {
background-color: #e01222;
color: #fff;
}
</style>
</head>
<body>
<div id="app">
<ul>
<li v-for="(item, index) in list" :key="item.id" @click="activeIndex = index">
<a :class="{ active: index === activeIndex }" href="#">{{ item.name }}</a>
</li>
</ul>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
activeIndex: 2, // 记录高亮
list: [
{ id: 1, name: '京东秒杀' },
{ id: 2, name: '每日特价' },
{ id: 3, name: '品类秒杀' }
]
}
})
</script>
</body>
</html>
4. v-bind对于样式操作的增强 - style
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.progress {
height: 25px;
width: 400px;
border-radius: 15px;
background-color: #272425;
border: 3px solid #272425;
box-sizing: border-box;
margin-bottom: 30px;
}
.inner {
width: 50%;
height: 20px;
border-radius: 10px;
text-align: right;
position: relative;
background-color: #409eff;
background-size: 20px 20px;
box-sizing: border-box;
transition: all 1s;
}
.inner span {
position: absolute;
right: -20px;
bottom: -25px;
}
</style>
</head>
<body>
<div id="app">
<!-- 外层盒子底色 （黑色） -->
<div class="progress">
<!-- 内层盒子 - 进度（蓝色） -->
<div class="inner" :style="{ width: percent + '%' }">
<span>{{ percent }}%</span>
</div>
</div>
<button @click="percent = 25">设置25%</button>
<button @click="percent = 50">设置50%</button>
<button @click="percent = 75">设置75%</button>
<button @click="percent = 100">设置100%</button>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
percent: 30
}
})
</script>
</body>
</html>
5. v-model应用于其他表单元素
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
textarea {
display: block;
width: 240px;
height: 100px;
margin: 10px 0;
}
</style>
</head>
<body>
<div id="app">
<h3>小黑学习网</h3>
姓名：
<input type="text" v-model="username">
<br><br>
是否单身：
<input type="checkbox" v-model="isSingle">
<br><br>
<!--
前置理解：
1. name: 给单选框加上 name 属性 可以分组 → 同一组互相会互斥
2. value: 给单选框加上 value 属性，用于提交给后台的数据
结合 Vue 使用 → v-model
-->
性别:
<input v-model="gender" type="radio" name="gender" value="1">男
<input v-model="gender" type="radio" name="gender" value="2">女
<br><br>
<!--
前置理解：
1. option 需要设置 value 值，提交给后台
2. select 的 value 值，关联了选中的 option 的 value 值
结合 Vue 使用 → v-model
-->
所在城市:
<select v-model="cityId">
<option value="101">北京</option>
<option value="102">上海</option>
<option value="103">成都</option>
<option value="104">南京</option>
</select>
<br><br>
自我描述：
<textarea v-model="desc"></textarea>
<button>立即注册</button>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
username: '',
isSingle: false,
gender: "2",
cityId: '102',
desc: ""
}
})
</script>
</body>
</html>
二、computed计算属性
1. 基础语法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
table {
border: 1px solid #000;
text-align: center;
width: 240px;
}
th,td {
border: 1px solid #000;
}
h3 {
position: relative;
}
</style>
</head>
<body>
<div id="app">
<h3>小黑的礼物清单</h3>
<table>
<tr>
<th>名字</th>
<th>数量</th>
</tr>
<tr v-for="(item, index) in list" :key="item.id">
<td>{{ item.name }}</td>
<td>{{ item.num }}个</td>
</tr>
</table>
<!-- 目标：统计求和，求得礼物总数 -->
<p>礼物总数：{{ totalCount }} 个</p>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
// 现有的数据
list: [
{ id: 1, name: '篮球', num: 1 },
{ id: 2, name: '玩具', num: 2 },
{ id: 3, name: '铅笔', num: 5 },
]
},
computed: {
totalCount () {
// 基于现有的数据，编写求值逻辑
// 计算属性函数内部，可以直接通过 this 访问到 app 实例
// console.log(this.list)
// 需求：对 this.list 数组里面的 num 进行求和 → reduce
let total = this.list.reduce((sum, item) => sum + item.num, 0)
return total
}
}
})
</script>
</body>
</html>
2. 计算属性 vS method 方法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
table {
border: 1px solid #000;
text-align: center;
width: 300px;
}
th,td {
border: 1px solid #000;
}
h3 {
position: relative;
}
span {
position: absolute;
left: 145px;
top: -4px;
width: 16px;
height: 16px;
color: white;
font-size: 12px;
text-align: center;
border-radius: 50%;
background-color: #e63f32;
}
</style>
</head>
<body>
<div id="app">
<h3>小黑的礼物清单🛒<span>{{ totalCountFn() }}</span></h3>
<h3>小黑的礼物清单🛒<span>{{ totalCountFn() }}</span></h3>
<h3>小黑的礼物清单🛒<span>{{ totalCountFn() }}</span></h3>
<h3>小黑的礼物清单🛒<span>{{ totalCountFn() }}</span></h3>
<table>
<tr>
<th>名字</th>
<th>数量</th>
</tr>
<tr v-for="(item, index) in list" :key="item.id">
<td>{{ item.name }}</td>
<td>{{ item.num }}个</td>
</tr>
</table>
<p>礼物总数：{{ totalCountFn() }} 个</p>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
// 现有的数据
list: [
{ id: 1, name: '篮球', num: 3 },
{ id: 2, name: '玩具', num: 2 },
{ id: 3, name: '铅笔', num: 5 },
]
},
methods: {
totalCountFn () {
console.log('methods方法执行了')
let total = this.list.reduce((sum, item) => sum + item.num, 0)
return total
}
},
computed: {
// 计算属性：有缓存的，一旦计算出来结果，就会立刻缓存
// 下一次读取 → 直接读缓存就行 → 性能特别高
// totalCount () {
// console.log('计算属性执行了')
// let total = this.list.reduce((sum, item) => sum + item.num, 0)
// return total
// }
}
})
</script>
</body>
</html>
3. 完整写法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
input {
width: 30px;
}
</style>
</head>
<body>
<div id="app">
姓：<input type="text" v-model="firstName"> +
名：<input type="text" v-model="lastName"> =
<span>{{ fullName }}</span><br><br>
<button @click="changeName">改名卡</button>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
firstName: '刘',
lastName: '备',
},
methods: {
changeName () {
this.fullName = '黄忠'
}
},
computed: {
// 简写 → 获取，没有配置设置的逻辑
// fullName () {
// return this.firstName + this.lastName
// }
// 完整写法 → 获取 + 设置
fullName: {
// (1) 当fullName计算属性，被获取求值时，执行get（有缓存，优先读缓存）
// 会将返回值作为，求值的结果
get () {
return this.firstName + this.lastName
},
// (2) 当fullName计算属性，被修改赋值时，执行set
// 修改的值，传递给set方法的形参
set (value) {
// console.log(value.slice(0, 1))
// console.log(value.slice(1))
this.firstName = value.slice(0, 1)
this.lastName = value.slice(1)
}
}
}
})
</script>
</body>
</html>
4. 成绩案例
- 渲染实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./styles/index.css" />
<title>Document</title>
</head>
<body>
<div id="app" class="score-case">
<div class="table">
<table>
<thead>
<tr>
<th>编号</th>
<th>科目</th>
<th>成绩</th>
<th>操作</th>
</tr>
</thead>
<tbody v-if="list.length > 0">
<tr v-for="(item, index) in list" :key="item.id">
<td>{{ index + 1 }}</td>
<td>{{ item.subject }}</td>
<!-- 需求：不及格的标红, < 60 分, 加上 red 类 -->
<td :class="{ red: item.score < 60 }">{{ item.score }}</td>
<td><a href="#">删除</a></td>
</tr>
</tbody>
<tbody v-else>
<tr>
<td colspan="5">
<span class="none">暂无数据</span>
</td>
</tr>
</tbody>
<tfoot>
<tr>
<td colspan="5">
<span>总分：246</span>
<span style="margin-left: 50px">平均分：79</span>
</td>
</tr>
</tfoot>
</table>
</div>
<div class="form">
<div class="form-item">
<div class="label">科目：</div>
<div class="input">
<input
type="text"
placeholder="请输入科目"
/>
</div>
</div>
<div class="form-item">
<div class="label">分数：</div>
<div class="input">
<input
type="text"
placeholder="请输入分数"
/>
</div>
</div>
<div class="form-item">
<div class="label"></div>
<div class="input">
<button class="submit" >添加</button>
</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
list: [
{ id: 1, subject: '语文', score: 62 },
{ id: 7, subject: '数学', score: 39 },
{ id: 12, subject: '英语', score: 70 },
],
subject: '',
score: ''
}
})
</script>
</body>
</html>
- 添加删除
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./styles/index.css" />
<title>Document</title>
</head>
<body>
<div id="app" class="score-case">
<div class="table">
<table>
<thead>
<tr>
<th>编号</th>
<th>科目</th>
<th>成绩</th>
<th>操作</th>
</tr>
</thead>
<tbody v-if="list.length > 0">
<tr v-for="(item, index) in list" :key="item.id">
<td>{{ index + 1 }}</td>
<td>{{ item.subject }}</td>
<!-- 需求：不及格的标红, < 60 分, 加上 red 类 -->
<td :class="{ red: item.score < 60 }">{{ item.score }}</td>
<td><a @click.prevent="del(item.id)" href="http://www.baidu.com">删除</a></td>
</tr>
</tbody>
<tbody v-else>
<tr>
<td colspan="5">
<span class="none">暂无数据</span>
</td>
</tr>
</tbody>
<tfoot>
<tr>
<td colspan="5">
<span>总分：246</span>
<span style="margin-left: 50px">平均分：79</span>
</td>
</tr>
</tfoot>
</table>
</div>
<div class="form">
<div class="form-item">
<div class="label">科目：</div>
<div class="input">
<input
type="text"
placeholder="请输入科目"
v-model.trim="subject"
/>
</div>
</div>
<div class="form-item">
<div class="label">分数：</div>
<div class="input">
<input
type="text"
placeholder="请输入分数"
v-model.number="score"
/>
</div>
</div>
<div class="form-item">
<div class="label"></div>
<div class="input">
<button @click="add" class="submit" >添加</button>
</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
list: [
{ id: 1, subject: '语文', score: 62 },
{ id: 7, subject: '数学', score: 39 },
{ id: 12, subject: '英语', score: 70 },
],
subject: '',
score: ''
},
methods: {
del (id) {
// console.log(id)
this.list = this.list.filter(item => item.id !== id)
},
add () {
if (!this.subject) {
alert('请输入科目')
return
}
if (typeof this.score !== 'number') {
alert('请输入正确的成绩')
return
}
this.list.unshift({
id: +new Date(),
subject: this.subject,
score: this.score
})
this.subject = ''
this.score = ''
}
}
})
</script>
</body>
</html>
- 计算属性
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./styles/index.css" />
<title>Document</title>
</head>
<body>
<div id="app" class="score-case">
<div class="table">
<table>
<thead>
<tr>
<th>编号</th>
<th>科目</th>
<th>成绩</th>
<th>操作</th>
</tr>
</thead>
<tbody v-if="list.length > 0">
<tr v-for="(item, index) in list" :key="item.id">
<td>{{ index + 1 }}</td>
<td>{{ item.subject }}</td>
<!-- 需求：不及格的标红, < 60 分, 加上 red 类 -->
<td :class="{ red: item.score < 60 }">{{ item.score }}</td>
<td><a @click.prevent="del(item.id)" href="http://www.baidu.com">删除</a></td>
</tr>
</tbody>
<tbody v-else>
<tr>
<td colspan="5">
<span class="none">暂无数据</span>
</td>
</tr>
</tbody>
<tfoot>
<tr>
<td colspan="5">
<span>总分：{{ totalScore }}</span>
<span style="margin-left: 50px">平均分：{{ averageScore }}</span>
</td>
</tr>
</tfoot>
</table>
</div>
<div class="form">
<div class="form-item">
<div class="label">科目：</div>
<div class="input">
<input
type="text"
placeholder="请输入科目"
v-model.trim="subject"
/>
</div>
</div>
<div class="form-item">
<div class="label">分数：</div>
<div class="input">
<input
type="text"
placeholder="请输入分数"
v-model.number="score"
/>
</div>
</div>
<div class="form-item">
<div class="label"></div>
<div class="input">
<button @click="add" class="submit" >添加</button>
</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
list: [
{ id: 1, subject: '语文', score: 62 },
{ id: 7, subject: '数学', score: 89 },
{ id: 12, subject: '英语', score: 70 },
],
subject: '',
score: ''
},
computed: {
totalScore() {
return this.list.reduce((sum, item) => sum + item.score, 0)
},
averageScore () {
if (this.list.length === 0) {
return 0
}
return (this.totalScore / this.list.length).toFixed(2)
}
},
methods: {
del (id) {
// console.log(id)
this.list = this.list.filter(item => item.id !== id)
},
add () {
if (!this.subject) {
alert('请输入科目')
return
}
if (typeof this.score !== 'number') {
alert('请输入正确的成绩')
return
}
this.list.unshift({
id: +new Date(),
subject: this.subject,
score: this.score
})
this.subject = ''
this.score = ''
}
}
})
</script>
</body>
</html>
三、watch 侦听器
1. 基础语法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
font-size: 18px;
}
#app {
padding: 10px 20px;
}
.query {
margin: 10px 0;
}
.box {
display: flex;
}
textarea {
width: 300px;
height: 160px;
font-size: 18px;
border: 1px solid #dedede;
outline: none;
resize: none;
padding: 10px;
}
textarea:hover {
border: 1px solid #1589f5;
}
.transbox {
width: 300px;
height: 160px;
background-color: #f0f0f0;
padding: 10px;
border: none;
}
.tip-box {
width: 300px;
height: 25px;
line-height: 25px;
display: flex;
}
.tip-box span {
flex: 1;
text-align: center;
}
.query span {
font-size: 18px;
}
.input-wrap {
position: relative;
}
.input-wrap span {
position: absolute;
right: 15px;
bottom: 15px;
font-size: 12px;
}
.input-wrap i {
font-size: 20px;
font-style: normal;
}
</style>
</head>
<body>
<div id="app">
<!-- 条件选择框 -->
<div class="query">
<span>翻译成的语言：</span>
<select>
<option value="italy">意大利</option>
<option value="english">英语</option>
<option value="german">德语</option>
</select>
</div>
<!-- 翻译框 -->
<div class="box">
<div class="input-wrap">
<textarea v-model="obj.words"></textarea>
<span><i>⌨️</i>文档翻译</span>
</div>
<div class="output-wrap">
<div class="transbox">mela</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>
<script>
// 接口地址：https://applet-base-api-t.itheima.net/api/translate
// 请求方式：get
// 请求参数：
// （1）words：需要被翻译的文本（必传）
// （2）lang： 需要被翻译成的语言（可选）默认值-意大利
// -----------------------------------------------
const app = new Vue({
el: '#app',
data: {
// words: ''
obj: {
words: ''
}
},
// 具体讲解：(1) watch语法 (2) 具体业务实现
watch: {
// 该方法会在数据变化时调用执行
// newValue新值, oldValue老值（一般不用）
// words (newValue) {
// console.log('变化了', newValue)
// }
'obj.words' (newValue) {
console.log('变化了', newValue)
}
}
})
</script>
</body>
</html>
2. 业务实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
font-size: 18px;
}
#app {
padding: 10px 20px;
}
.query {
margin: 10px 0;
}
.box {
display: flex;
}
textarea {
width: 300px;
height: 160px;
font-size: 18px;
border: 1px solid #dedede;
outline: none;
resize: none;
padding: 10px;
}
textarea:hover {
border: 1px solid #1589f5;
}
.transbox {
width: 300px;
height: 160px;
background-color: #f0f0f0;
padding: 10px;
border: none;
}
.tip-box {
width: 300px;
height: 25px;
line-height: 25px;
display: flex;
}
.tip-box span {
flex: 1;
text-align: center;
}
.query span {
font-size: 18px;
}
.input-wrap {
position: relative;
}
.input-wrap span {
position: absolute;
right: 15px;
bottom: 15px;
font-size: 12px;
}
.input-wrap i {
font-size: 20px;
font-style: normal;
}
</style>
</head>
<body>
<div id="app">
<!-- 条件选择框 -->
<div class="query">
<span>翻译成的语言：</span>
<select>
<option value="italy">意大利</option>
<option value="english">英语</option>
<option value="german">德语</option>
</select>
</div>
<!-- 翻译框 -->
<div class="box">
<div class="input-wrap">
<textarea v-model="obj.words"></textarea>
<span><i>⌨️</i>文档翻译</span>
</div>
<div class="output-wrap">
<div class="transbox">{{ result }}</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>
<script>
// 接口地址：https://applet-base-api-t.itheima.net/api/translate
// 请求方式：get
// 请求参数：
// （1）words：需要被翻译的文本（必传）
// （2）lang： 需要被翻译成的语言（可选）默认值-意大利
// -----------------------------------------------
const app = new Vue({
el: '#app',
data: {
// words: ''
obj: {
words: ''
},
result: '', // 翻译结果
// timer: null // 延时器id
},
// 具体讲解：(1) watch语法 (2) 具体业务实现
watch: {
// 该方法会在数据变化时调用执行
// newValue新值, oldValue老值（一般不用）
// words (newValue) {
// console.log('变化了', newValue)
// }
'obj.words' (newValue) {
// console.log('变化了', newValue)
// 防抖: 延迟执行 → 干啥事先等一等，延迟一会，一段时间内没有再次触发，才执行
clearTimeout(this.timer)
this.timer = setTimeout(async () => {
const res = await axios({
url: 'https://applet-base-api-t.itheima.net/api/translate',
params: {
words: newValue
}
})
this.result = res.data.data
console.log(res.data.data)
}, 300)
}
}
})
</script>
</body>
</html>
3. 完整写法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
font-size: 18px;
}
#app {
padding: 10px 20px;
}
.query {
margin: 10px 0;
}
.box {
display: flex;
}
textarea {
width: 300px;
height: 160px;
font-size: 18px;
border: 1px solid #dedede;
outline: none;
resize: none;
padding: 10px;
}
textarea:hover {
border: 1px solid #1589f5;
}
.transbox {
width: 300px;
height: 160px;
background-color: #f0f0f0;
padding: 10px;
border: none;
}
.tip-box {
width: 300px;
height: 25px;
line-height: 25px;
display: flex;
}
.tip-box span {
flex: 1;
text-align: center;
}
.query span {
font-size: 18px;
}
.input-wrap {
position: relative;
}
.input-wrap span {
position: absolute;
right: 15px;
bottom: 15px;
font-size: 12px;
}
.input-wrap i {
font-size: 20px;
font-style: normal;
}
</style>
</head>
<body>
<div id="app">
<!-- 条件选择框 -->
<div class="query">
<span>翻译成的语言：</span>
<select v-model="obj.lang">
<option value="italy">意大利</option>
<option value="english">英语</option>
<option value="german">德语</option>
</select>
</div>
<!-- 翻译框 -->
<div class="box">
<div class="input-wrap">
<textarea v-model="obj.words"></textarea>
<span><i>⌨️</i>文档翻译</span>
</div>
<div class="output-wrap">
<div class="transbox">{{ result }}</div>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>
<script>
// 需求：输入内容，修改语言，都实时翻译
// 接口地址：https://applet-base-api-t.itheima.net/api/translate
// 请求方式：get
// 请求参数：
// （1）words：需要被翻译的文本（必传）
// （2）lang： 需要被翻译成的语言（可选）默认值-意大利
// -----------------------------------------------
const app = new Vue({
el: '#app',
data: {
obj: {
words: '小黑',
lang: 'italy'
},
result: '', // 翻译结果
},
watch: {
obj: {
deep: true, // 深度监视
immediate: true, // 立刻执行，一进入页面handler就立刻执行一次
handler (newValue) {
clearTimeout(this.timer)
this.timer = setTimeout(async () => {
const res = await axios({
url: 'https://applet-base-api-t.itheima.net/api/translate',
params: newValue
})
this.result = res.data.data
console.log(res.data.data)
}, 300)
}
}
// 'obj.words' (newValue) {
// clearTimeout(this.timer)
// this.timer = setTimeout(async () => {
// const res = await axios({
// url: 'https://applet-base-api-t.itheima.net/api/translate',
// params: {
// words: newValue
// }
// })
// this.result = res.data.data
// console.log(res.data.data)
// }, 300)
// }
}
})
</script>
</body>
</html>
四、综合案例:水果购物车
1. 渲染
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./css/inputnumber.css" />
<link rel="stylesheet" href="./css/index.css" />
<title>购物车</title>
</head>
<body>
<div class="app-container" id="app">
<!-- 顶部banner -->
<div class="banner-box"><img src="http://autumnfish.cn/static/fruit.jpg" alt="" /></div>
<!-- 面包屑 -->
<div class="breadcrumb">
<span>🏠</span>
/
<span>购物车</span>
</div>
<!-- 购物车主体 -->
<div class="main" v-if="fruitList.length > 0">
<div class="table">
<!-- 头部 -->
<div class="thead">
<div class="tr">
<div class="th">选中</div>
<div class="th th-pic">图片</div>
<div class="th">单价</div>
<div class="th num-th">个数</div>
<div class="th">小计</div>
<div class="th">操作</div>
</div>
</div>
<!-- 身体 -->
<div class="tbody">
<div v-for="(item, index) in fruitList" :key="item.id" class="tr" :class="{ active: item.isChecked }">
<div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
<div class="td"><img :src="item.icon" alt="" /></div>
<div class="td">{{ item.price }}</div>
<div class="td">
<div class="my-input-number">
<button class="decrease"> - </button>
<span class="my-input__inner">{{ item.num }}</span>
<button class="increase"> + </button>
</div>
</div>
<div class="td">{{ item.num * item.price }}</div>
<div class="td"><button>删除</button></div>
</div>
</div>
</div>
<!-- 底部 -->
<div class="bottom">
<!-- 全选 -->
<label class="check-all">
<input type="checkbox" />
全选
</label>
<div class="right-box">
<!-- 所有商品总价 -->
<span class="price-box">总价 : ¥ <span class="price">24</span></span>
<!-- 结算按钮 -->
<button class="pay">结算( 6 )</button>
</div>
</div>
</div>
<!-- 空车 -->
<div class="empty" v-else>🛒空空如也</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
// 水果列表
fruitList: [
{
id: 1,
icon: 'http://autumnfish.cn/static/火龙果.png',
isChecked: true,
num: 2,
price: 6,
},
{
id: 2,
icon: 'http://autumnfish.cn/static/荔枝.png',
isChecked: false,
num: 7,
price: 20,
},
{
id: 3,
icon: 'http://autumnfish.cn/static/榴莲.png',
isChecked: false,
num: 3,
price: 40,
},
{
id: 4,
icon: 'http://autumnfish.cn/static/鸭梨.png',
isChecked: true,
num: 10,
price: 3,
},
{
id: 5,
icon: 'http://autumnfish.cn/static/樱桃.png',
isChecked: false,
num: 20,
price: 34,
},
],
},
})
</script>
</body>
</html>
2. 删除和修改数量
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./css/inputnumber.css" />
<link rel="stylesheet" href="./css/index.css" />
<title>购物车</title>
</head>
<body>
<div class="app-container" id="app">
<!-- 顶部banner -->
<div class="banner-box"><img src="http://autumnfish.cn/static/fruit.jpg" alt="" /></div>
<!-- 面包屑 -->
<div class="breadcrumb">
<span>🏠</span>
/
<span>购物车</span>
</div>
<!-- 购物车主体 -->
<div class="main" v-if="fruitList.length > 0">
<div class="table">
<!-- 头部 -->
<div class="thead">
<div class="tr">
<div class="th">选中</div>
<div class="th th-pic">图片</div>
<div class="th">单价</div>
<div class="th num-th">个数</div>
<div class="th">小计</div>
<div class="th">操作</div>
</div>
</div>
<!-- 身体 -->
<div class="tbody">
<div v-for="(item, index) in fruitList" :key="item.id" class="tr" :class="{ active: item.isChecked }">
<div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
<div class="td"><img :src="item.icon" alt="" /></div>
<div class="td">{{ item.price }}</div>
<div class="td">
<div class="my-input-number">
<button :disabled="item.num <= 1" class="decrease" @click="sub(item.id)"> - </button>
<span class="my-input__inner">{{ item.num }}</span>
<button class="increase" @click="add(item.id)"> + </button>
</div>
</div>
<div class="td">{{ item.num * item.price }}</div>
<div class="td"><button @click="del(item.id)">删除</button></div>
</div>
</div>
</div>
<!-- 底部 -->
<div class="bottom">
<!-- 全选 -->
<label class="check-all">
<input type="checkbox" />
全选
</label>
<div class="right-box">
<!-- 所有商品总价 -->
<span class="price-box">总价 : ¥ <span class="price">24</span></span>
<!-- 结算按钮 -->
<button class="pay">结算( 6 )</button>
</div>
</div>
</div>
<!-- 空车 -->
<div class="empty" v-else>🛒空空如也</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
// 水果列表
fruitList: [
{
id: 1,
icon: 'http://autumnfish.cn/static/火龙果.png',
isChecked: true,
num: 2,
price: 6,
},
{
id: 2,
icon: 'http://autumnfish.cn/static/荔枝.png',
isChecked: false,
num: 7,
price: 20,
},
{
id: 3,
icon: 'http://autumnfish.cn/static/榴莲.png',
isChecked: false,
num: 3,
price: 40,
},
{
id: 4,
icon: 'http://autumnfish.cn/static/鸭梨.png',
isChecked: true,
num: 10,
price: 3,
},
{
id: 5,
icon: 'http://autumnfish.cn/static/樱桃.png',
isChecked: false,
num: 20,
price: 34,
},
],
},
methods: {
del (id) {
this.fruitList = this.fruitList.filter(item => item.id !== id)
},
add (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num++
},
sub (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num--
}
}
})
</script>
</body>
</html>
3. 全选反选
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./css/inputnumber.css" />
<link rel="stylesheet" href="./css/index.css" />
<title>购物车</title>
</head>
<body>
<div class="app-container" id="app">
<!-- 顶部banner -->
<div class="banner-box"><img src="http://autumnfish.cn/static/fruit.jpg" alt="" /></div>
<!-- 面包屑 -->
<div class="breadcrumb">
<span>🏠</span>
/
<span>购物车</span>
</div>
<!-- 购物车主体 -->
<div class="main" v-if="fruitList.length > 0">
<div class="table">
<!-- 头部 -->
<div class="thead">
<div class="tr">
<div class="th">选中</div>
<div class="th th-pic">图片</div>
<div class="th">单价</div>
<div class="th num-th">个数</div>
<div class="th">小计</div>
<div class="th">操作</div>
</div>
</div>
<!-- 身体 -->
<div class="tbody">
<div v-for="(item, index) in fruitList" :key="item.id" class="tr" :class="{ active: item.isChecked }">
<div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
<div class="td"><img :src="item.icon" alt="" /></div>
<div class="td">{{ item.price }}</div>
<div class="td">
<div class="my-input-number">
<button :disabled="item.num <= 1" class="decrease" @click="sub(item.id)"> - </button>
<span class="my-input__inner">{{ item.num }}</span>
<button class="increase" @click="add(item.id)"> + </button>
</div>
</div>
<div class="td">{{ item.num * item.price }}</div>
<div class="td"><button @click="del(item.id)">删除</button></div>
</div>
</div>
</div>
<!-- 底部 -->
<div class="bottom">
<!-- 全选 -->
<label class="check-all">
<input type="checkbox" v-model="isAll"/>
全选
</label>
<div class="right-box">
<!-- 所有商品总价 -->
<span class="price-box">总价 : ¥ <span class="price">24</span></span>
<!-- 结算按钮 -->
<button class="pay">结算( 6 )</button>
</div>
</div>
</div>
<!-- 空车 -->
<div class="empty" v-else>🛒空空如也</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
// 水果列表
fruitList: [
{
id: 1,
icon: 'http://autumnfish.cn/static/火龙果.png',
isChecked: true,
num: 2,
price: 6,
},
{
id: 2,
icon: 'http://autumnfish.cn/static/荔枝.png',
isChecked: false,
num: 7,
price: 20,
},
{
id: 3,
icon: 'http://autumnfish.cn/static/榴莲.png',
isChecked: false,
num: 3,
price: 40,
},
{
id: 4,
icon: 'http://autumnfish.cn/static/鸭梨.png',
isChecked: true,
num: 10,
price: 3,
},
{
id: 5,
icon: 'http://autumnfish.cn/static/樱桃.png',
isChecked: false,
num: 20,
price: 34,
},
],
},
computed: {
// 默认计算属性：只能获取不能设置，要设置需要写完整写法
// isAll () {
// // 必须所有的小选框都选中，全选按钮才选中 → every
// return this.fruitList.every(item => item.isChecked)
// }
// 完整写法 = get + set
isAll: {
get () {
return this.fruitList.every(item => item.isChecked)
},
set (value) {
// 基于拿到的布尔值，要让所有的小选框 同步状态
this.fruitList.forEach(item => item.isChecked = value)
}
}
},
methods: {
del (id) {
this.fruitList = this.fruitList.filter(item => item.id !== id)
},
add (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num++
},
sub (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num--
}
}
})
</script>
</body>
</html>
4. 统计总价
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./css/inputnumber.css" />
<link rel="stylesheet" href="./css/index.css" />
<title>购物车</title>
</head>
<body>
<div class="app-container" id="app">
<!-- 顶部banner -->
<div class="banner-box"><img src="http://autumnfish.cn/static/fruit.jpg" alt="" /></div>
<!-- 面包屑 -->
<div class="breadcrumb">
<span>🏠</span>
/
<span>购物车</span>
</div>
<!-- 购物车主体 -->
<div class="main" v-if="fruitList.length > 0">
<div class="table">
<!-- 头部 -->
<div class="thead">
<div class="tr">
<div class="th">选中</div>
<div class="th th-pic">图片</div>
<div class="th">单价</div>
<div class="th num-th">个数</div>
<div class="th">小计</div>
<div class="th">操作</div>
</div>
</div>
<!-- 身体 -->
<div class="tbody">
<div v-for="(item, index) in fruitList" :key="item.id" class="tr" :class="{ active: item.isChecked }">
<div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
<div class="td"><img :src="item.icon" alt="" /></div>
<div class="td">{{ item.price }}</div>
<div class="td">
<div class="my-input-number">
<button :disabled="item.num <= 1" class="decrease" @click="sub(item.id)"> - </button>
<span class="my-input__inner">{{ item.num }}</span>
<button class="increase" @click="add(item.id)"> + </button>
</div>
</div>
<div class="td">{{ item.num * item.price }}</div>
<div class="td"><button @click="del(item.id)">删除</button></div>
</div>
</div>
</div>
<!-- 底部 -->
<div class="bottom">
<!-- 全选 -->
<label class="check-all">
<input type="checkbox" v-model="isAll"/>
全选
</label>
<div class="right-box">
<!-- 所有商品总价 -->
<span class="price-box">总价 : ¥ <span class="price">{{ totalPrice }}</span></span>
<!-- 结算按钮 -->
<button class="pay">结算( {{ totalCount }} )</button>
</div>
</div>
</div>
<!-- 空车 -->
<div class="empty" v-else>🛒空空如也</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el: '#app',
data: {
// 水果列表
fruitList: [
{
id: 1,
icon: 'http://autumnfish.cn/static/火龙果.png',
isChecked: true,
num: 2,
price: 6,
},
{
id: 2,
icon: 'http://autumnfish.cn/static/荔枝.png',
isChecked: false,
num: 7,
price: 20,
},
{
id: 3,
icon: 'http://autumnfish.cn/static/榴莲.png',
isChecked: false,
num: 3,
price: 40,
},
{
id: 4,
icon: 'http://autumnfish.cn/static/鸭梨.png',
isChecked: true,
num: 10,
price: 3,
},
{
id: 5,
icon: 'http://autumnfish.cn/static/樱桃.png',
isChecked: false,
num: 20,
price: 34,
},
],
},
computed: {
// 默认计算属性：只能获取不能设置，要设置需要写完整写法
// isAll () {
// // 必须所有的小选框都选中，全选按钮才选中 → every
// return this.fruitList.every(item => item.isChecked)
// }
// 完整写法 = get + set
isAll: {
get () {
return this.fruitList.every(item => item.isChecked)
},
set (value) {
// 基于拿到的布尔值，要让所有的小选框 同步状态
this.fruitList.forEach(item => item.isChecked = value)
}
},
// 统计选中的总数 reduce
totalCount () {
return this.fruitList.reduce((sum, item) => {
if (item.isChecked) {
// 选中 → 需要累加
return sum + item.num
} else {
// 没选中 → 不需要累加
return sum
}
}, 0)
},
// 总计选中的总价 num * price
totalPrice () {
return this.fruitList.reduce((sum, item) => {
if (item.isChecked) {
return sum + item.num * item.price
} else {
return sum
}
}, 0)
}
},
methods: {
del (id) {
this.fruitList = this.fruitList.filter(item => item.id !== id)
},
add (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num++
},
sub (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num--
}
}
})
</script>
</body>
</html>
5. 本地持久化
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="./css/inputnumber.css" />
<link rel="stylesheet" href="./css/index.css" />
<title>购物车</title>
</head>
<body>
<div class="app-container" id="app">
<!-- 顶部banner -->
<div class="banner-box"><img src="http://autumnfish.cn/static/fruit.jpg" alt="" /></div>
<!-- 面包屑 -->
<div class="breadcrumb">
<span>🏠</span>
/
<span>购物车</span>
</div>
<!-- 购物车主体 -->
<div class="main" v-if="fruitList.length > 0">
<div class="table">
<!-- 头部 -->
<div class="thead">
<div class="tr">
<div class="th">选中</div>
<div class="th th-pic">图片</div>
<div class="th">单价</div>
<div class="th num-th">个数</div>
<div class="th">小计</div>
<div class="th">操作</div>
</div>
</div>
<!-- 身体 -->
<div class="tbody">
<div v-for="(item, index) in fruitList" :key="item.id" class="tr" :class="{ active: item.isChecked }">
<div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
<div class="td"><img :src="item.icon" alt="" /></div>
<div class="td">{{ item.price }}</div>
<div class="td">
<div class="my-input-number">
<button :disabled="item.num <= 1" class="decrease" @click="sub(item.id)"> - </button>
<span class="my-input__inner">{{ item.num }}</span>
<button class="increase" @click="add(item.id)"> + </button>
</div>
</div>
<div class="td">{{ item.num * item.price }}</div>
<div class="td"><button @click="del(item.id)">删除</button></div>
</div>
</div>
</div>
<!-- 底部 -->
<div class="bottom">
<!-- 全选 -->
<label class="check-all">
<input type="checkbox" v-model="isAll"/>
全选
</label>
<div class="right-box">
<!-- 所有商品总价 -->
<span class="price-box">总价 : ¥ <span class="price">{{ totalPrice }}</span></span>
<!-- 结算按钮 -->
<button class="pay">结算( {{ totalCount }} )</button>
</div>
</div>
</div>
<!-- 空车 -->
<div class="empty" v-else>🛒空空如也</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const defaultArr = [
{
id: 1,
icon: 'http://autumnfish.cn/static/火龙果.png',
isChecked: true,
num: 2,
price: 6,
},
{
id: 2,
icon: 'http://autumnfish.cn/static/荔枝.png',
isChecked: false,
num: 7,
price: 20,
},
{
id: 3,
icon: 'http://autumnfish.cn/static/榴莲.png',
isChecked: false,
num: 3,
price: 40,
},
{
id: 4,
icon: 'http://autumnfish.cn/static/鸭梨.png',
isChecked: true,
num: 10,
price: 3,
},
{
id: 5,
icon: 'http://autumnfish.cn/static/樱桃.png',
isChecked: false,
num: 20,
price: 34,
},
]
const app = new Vue({
el: '#app',
data: {
// 水果列表
fruitList: JSON.parse(localStorage.getItem('list')) || defaultArr,
},
computed: {
// 默认计算属性：只能获取不能设置，要设置需要写完整写法
// isAll () {
// // 必须所有的小选框都选中，全选按钮才选中 → every
// return this.fruitList.every(item => item.isChecked)
// }
// 完整写法 = get + set
isAll: {
get () {
return this.fruitList.every(item => item.isChecked)
},
set (value) {
// 基于拿到的布尔值，要让所有的小选框 同步状态
this.fruitList.forEach(item => item.isChecked = value)
}
},
// 统计选中的总数 reduce
totalCount () {
return this.fruitList.reduce((sum, item) => {
if (item.isChecked) {
// 选中 → 需要累加
return sum + item.num
} else {
// 没选中 → 不需要累加
return sum
}
}, 0)
},
// 总计选中的总价 num * price
totalPrice () {
return this.fruitList.reduce((sum, item) => {
if (item.isChecked) {
return sum + item.num * item.price
} else {
return sum
}
}, 0)
}
},
methods: {
del (id) {
this.fruitList = this.fruitList.filter(item => item.id !== id)
},
add (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num++
},
sub (id) {
// 1. 根据 id 找到数组中的对应项 → find
const fruit = this.fruitList.find(item => item.id === id)
// 2. 操作 num 数量
fruit.num--
}
},
watch: {
fruitList: {
deep: true,
handler (newValue) {
// 需要将变化后的 newValue 存入本地 （转JSON）
localStorage.setItem('list', JSON.stringify(newValue))
}
}
}
})
</script>
</body>
</html>
总结
欢迎各位留言交流以及批评指正，如果文章对您有帮助或者觉得作者写的还不错可以点一下关注,点赞，收藏支持一下。
（博客的参考源码可以在我主页的资源里找到，如果在学习的过程中有什么疑问欢迎大家在评论区向我提出）
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