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 → reducelet 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"><inputtype="text"placeholder="请输入科目"/></div></div><div class="form-item"><div class="label">分数：</div><div class="input"><inputtype="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"><inputtype="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"><inputtype="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"><inputtype="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"><inputtype="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.dataconsole.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.dataconsole.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 → findconst 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 → findconst 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 + setisAll: {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 → findconst 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 → findconst 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 + setisAll: {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 reducetotalCount () {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 * pricetotalPrice () {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 → findconst 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 → findconst 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 + setisAll: {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 reducetotalCount () {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 * pricetotalPrice () {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 → findconst 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 → findconst 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）
