饮冰三年-人工智能-Vue-47 初识Vue

一、初识Vue

1、读音

　　Vue：/vju:/。类似于View

2、定义

　　是一个构建用户界面的渐进式框架。

渐进式意味着你可以将Vue作为你应用的一部分（先画一个圈）嵌入其中，带来更丰富的交互体验。
当然也有全家桶：比如Core+Vue-router+Vuex，也可以满足你各种各样的需求。

3、安装

直接CDN引入
下载和引入
NPM安装

二、Hello Vue

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./static/vue.min.js"></script>
</head>
<body>
    <div id="app">{{sayHi}}</div>
    <script>
        //数据模板引擎
        new Vue({
            el:"#app",
            data:{
                sayHi:"Hello,Vue!"
            }
        })
    </script>
</body>
</html>

安装vue（下载并引入vue.js）+Hello Vue

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8" />
        <title></title>
        <script src="js/vue.js" type="text/javascript"></script>
    </head>
    <body>
        <div id="app">
            <h2>当前计数：{{counter}}</h2>
            <button v-on:click="add">+</button>
            <button v-on:click="sub">-</button>
        </div>
        <script>
            const app = new Vue({
                el: "#app",
                data: {
                    counter: 0
                },
                methods:{
                    add:function(){
                        this.counter=this.counter+1;
                    },
                    sub:function(){
                        this.counter=this.counter-1;
                    }
                }
            })
        </script>
    </body>
</html>

计数器

特点

编程范式：命令式和声明式。js属于命令式，Vue属于声明式。
响应式：Vue属于数据响应式视图。通过数据的变化从而影响页面视图的展示
{{}}，mustache语法
new Vue 中的 options 属性。
- 　　el：类型：string | HTMLElement；
- 　　el：作用：决定之后Vue实例会管理哪一个DOM
- 　　data：类型：object|Function；
- 　　data：作用：Vue实例对应的数据对象
- methods：类型：{[key:string]:function}
- methods：作用：定义属于Vue的方法，可以在其他地方调用，也可以在指令中使用

MVVM

View：视图层，DOM层，给用户展示各种信息。
Model：数据层，固定数据、服务器、网络上请求下来。
VueModel：视图模型，View和Model沟通的桥梁。
1：它实现了数据绑定（DataBinding），将Model的改变实时的反映到View中
2：它实现了DOM监听（DOM Listener），当DOM发生一些事件（点击、滚动、touch等），可以监听，并在需要的情况下改变对应的Data

三、指令

1、插值指令

        <body> 
        <div id="app" v-once>
             {{once}}
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    once:"表示元素和组件只渲染一次!"
                },
                 
            })
        </script>
    </body>

v-once

<body>
    <div id="app" v-text="sayHi"></div>
    <script>
        //数据模板引擎
        new Vue({
            el:"#app",
            data:{
                sayHi:"Hello,Vue!"
            }
        })
    </script>
</body>

v-text

<body>
        <div id="app" v-html="sayHi">    </div>
        <script>
            new Vue({
                    el: "#app",
                    data: {
                        sayHi: "<h1>Hello, Vue</h1>"
                    }
                }

            )
        </script>
    </body>

v-html:含有html标签语言的

        <body> 
        <div id="app" v-pre>
             {{pre}}
        </div>
        
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    pre:"将代码原封不动的解析出来!"
                },
                 
            })
        </script>
    </body>

v-pre

    <body>
        <style>
            [v-cloak]{
                display: none;
            }
        </style>
        <div id="app" v-cloak>
            {{pre}}
        </div>

        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            setTimeout(function() {
                let app = new Vue({
                    el: "#app",
                    data: {
                        pre: "斗篷函数!"
                    },

                })
            }, 1000)
        </script>
    </body>

v-cloak

<div id="app3">
            <ul>
                <li v-for="aihao in hobby">{{aihao}}</li>
            </ul>
</div>
<script>
new Vue({
                    el: "#app3",
                    data: {
                        hobby: ["跑步", "游泳",
                            "阅读"
                        ],
                    }
                }

            )
</script>

for循环

2、属性绑定指令 v-bind

        <body>
        <div id="app">
            <a :href="baidu">百度一下</a>
            <img :src="imgSrc">
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    baidu: "https://www.baidu.com/",
                    imgSrc: "https://imgsrc.baidu.com/baike/pic/item/0df3d7ca7bcb0a4661ab1f6c6463f6246a60afde.jpg"
                },

            })
        </script>
    </body>

:href与:src

<body>
        <div id="app">
            <div :class="['class1','class2']">数组语法</div>
            <div :class="arryClass">数组语法2</div>
            <div :class="{'class5':true,'class6':false}">对象语法</div>
            <div :class="{'class7':isclass7,'class8':isclass8}">对象语法2</div>
            <div :class="getObjClass()">对象语法3</div>
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    arryClass: ['class3', 'class4'],
                    isclass7: true,
                    isclass8: false,
                },
                methods: {
                    getObjClass: function() {
                        return {'class9':true,'class10':false}
                    }
                }

            })
        </script>
    </body>

v-bind:class

<body>
        <div id="app">
            <div :style="[redFont, bFont]">数组语法</div>
            <div :style="{color:'blue',fontSize:'10px'}">对象语法</div>
            <div :style="{fontSize:curSize}">对象语法2</div>
            <div :style="getObjStyle()">对象语法3</div>
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    redFont: {
                        color: 'red'
                    },
                    bFont: {
                        fontSize: "20px"
                    },
                    curSize:"15px"
                },
                methods: {
                    getObjStyle: function() {
                        return {
                            color: 'yellow',
                            fontSize: '40px'
                        }
                    }
                }

            })
        </script>
    </body>

v-bind:style

    <head>
        <meta charset="utf-8">
        <title></title>
        <style type="text/css">
            .active {
                color: red;
            }
        </style>
    </head>
    <body>
        <div id="app">
            <ul>
                <li v-on:click="changeColor(index)" v-bind:class="{active:i==index}" v-for="(item,index) in movies">{{index}}--{{item}}</li>
            </ul>
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    movies: ["阿甘正传", "教父", "最后一课"],
                    i: false
                },
                methods: {
                    changeColor(index) {
                        this.i = index
                    }
                }
            })
        </script>
    </body>

vue-练习点击变红

3、计算属性 computed

    <body>
        <div id="app">
            {{fullName}}:{{TotalPrice}}
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    firstName: "张",
                    lastName: "三",
                    books: [{
                            id: "001",
                            name: "深入理解Python",
                            price: 100,
                            count: 3
                        },
                        {
                            id: "002",
                            name: "深入理解Vue",
                            price: 200,
                            count: 2
                        }
                    ]
                },
                computed: {
                    fullName: function() {
                        return this.firstName + this.lastName
                    },
                    TotalPrice: function() {
                        return this.books.reduce((total, bo) => {
                            return total + bo.price * bo.count
                        }, 0)
                    }
                }
            })
        </script>
    </body>

computed

        <div id="app9">
            <input v-model="num1" />
            +
            <input v-model="num2" />
            = {{sum}}
        </div>
        <script>
            new Vue({
                    el: "#app9",
                    data: {
                        num1: 0,
                        num2: 0,
                    },
                    computed: {
                        sum:function() {
                             return parseInt(this.num1) + parseInt(this.num2);
                        }
                    },
                    
                }
            )
        </script>

computed 计算函数

<body>
        <div id="app">
            {{fullName}}
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    firstName: "张",
                    lastName: "三"
                },
                computed: {
                    fullName: {
                        set(str) {
                            const arryStr = str.split(" ")
                            this.firstName = arryStr[0]
                            this.lastName = arryStr[1]
                        },
                        get() {
                            return this.firstName + this.lastName
                        }
                    }
                }
            })
        </script>
    </body>

计算属性的set()与get()

    <body>
        <div id="app">
            {{fullName}}
            {{fullName}}
            {{fullName}}
            {{fullName}}
            {{getFullName()}}
            {{getFullName()}}
            {{getFullName()}}
            {{getFullName()}}
             
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {
                    firstName: "张",
                    lastName: "三"
                },
                computed: {
                    fullName() {
                        console.log("computed，调用次数")
                        return this.firstName + this.lastName
                    }
                },
                methods:{
                    getFullName(){
                        console.log("methods，调用次数")
                        return this.firstName + this.lastName
                    }
                }
            })
        </script>
    </body>

computed与computed的区别

computed与methods的区别

computed是属性调用，而methods是函数调用
computed带有缓存功能，而methods不是
computed定义的方法我们是以属性访问的形式调用的，{{computedTest}}
但是methods定义的方法，我们必须要加上()来调用，如{{methodTest()}}

4、事件监听 v-on

<body>
        <div id="app" @click="divClick">
            divClick
            <button type="button" v-on:click="sayHello">sayHello</button>
            <button type="button" @click="sayHi('张三')">sayHi</button>
            <button type="button" @click.stop="btnClick">防止冒泡</button>
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            let app = new Vue({
                el: "#app",
                data: {

                },
                methods: {
                    sayHello() {
                        console.log("Hello,World!");
                    },
                    sayHi(strName) {
                        console.log("Hello," + strName + "!");
                    },
                    divClick(){
                        console.log("hello，Div");
                    },
                    btnClick(){
                        console.log("hello，Btn");
                    }
                }
            })
        </script>
    </body>

v-on:click

5、分支判断

<div id="app5">
            <ul>
                <li v-if="score>80">优秀</li>
                <li v-else-if="score>60" >及格</li>
                <li v-else="score">补考</li>
            </ul>
</div>
<script>
        new Vue({
                    el: "#app5",
                    data: {
                        score:16,
                    }
                }
            
            )
</script>

v-if & v-else-if & v-else

<body>
        <div id="app">
            <ul>
                <li v-if="score>80">优秀</li>
                <li v-show="score>80">优秀</li>
                <li v-show="score<60">不及格</li>
            </ul>
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            new Vue({
                    el: "#app",
                    data: {
                        score: 16,
                    }
                }

            )
        </script>
    </body>

v-show与v-if的区别

6、循环

    <div id="app">
            <ul>
                <li v-for="item in movies">{{item}}</li>
            </ul>
            <ul>
                <li v-for="(item,index) in movies">{{index+1}}----{{item}}</li>
            </ul>
            <br>
            <!-- 循环obj对象 -->
            <ul>
                <li v-for="item in objMovies">{{item}}</li>
            </ul>
            <ul>
                <li v-for="(value,key) in objMovies">{{key}}---{{value}}</li>
            </ul>
            <ul>
                <li v-for="(value,key,index) in objMovies">{{index+1}}---{{key}}---{{value}}</li>
            </ul>
            <ul>
                <li v-for="(value) in objMovies" :key="value"> {{value}}</li>
            </ul>
        </div>
        <script src="js/vue.js" type="text/javascript"></script>
        <script>
            new Vue({
                el: "#app",
                data: {
                    movies: ["阿甘正传", "教父", "最后一课"],
                    objMovies: {
                        name: "狮子王",
                        price: "200",
                        addr: "国家大剧院"
                    },
                },
            })
        </script>

for循环

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 
 4 <head>
 5   <meta charset="UTF-8">
 6   <title>Document</title>
 7   <link rel="stylesheet" href="style.css">
 8 </head>
 9 
10 <body>
11   <div id="app">
12     <div v-if="books.length">
13       <table>
14         <thead>
15           <tr>
16             <th>编号</th>
17             <th>名称</th>
18             <th>出版日期</th>
19             <th>价格</th>
20             <th>数量</th>
21             <th>操作</th>
22           </tr>
23         </thead>
24         <tbody>
25           <tr v-for="(item,index) in books">
26             <td>{{item.id}}</td>
27             <td>{{item.name}}</td>
28             <td>{{item.date}}</td>
29             <td>{{item.price|showPrice}}</td>
30             <td><button @click="sub(item)" :disabled="item.count<=1">-</button>{{item.count}}<button @click="add(item)">+</button></td>
31             <td><button @click="removeHandle(index)">删除</button></td>
32           </tr>
33         </tbody>
34       </table>
35       <h2>总价格{{totalPrice|showPrice}}</h2>
36     </div>
37     <h2 v-else>购物车为空</h2>
38   </div>
39   <script src="https://cdn.jsdelivr.net/npm/vue@2.6.13/dist/vue.js"></script>
40   <script src="main.js"></script>
41 </body>
42 
43 </html>

VUE练习购物车之html

const app = new Vue({
  el: "#app",
  data: {
    books: [
      {
        id: 1,
        name: "《算法导论》",
        date: "2020-01-01",
        price: 85.0,
        count: 1
      },
      {
        id: 2,
        name: "《流畅的python》",
        date: "2022-11-01",
        price: 105.0,
        count: 1
      },
      {
        id: 1,
        name: "《Java入门》",
        date: "2021-05-03",
        price: 95.0,
        count: 1
      },
      { id: 1, name: "《VUE》", date: "2022-11-01", price: 55.0, count: 1 }
    ],
  },
  methods: {
    removeHandle(index) {
      this.books.splice(index, 1)
    },
    add(item){
      item.count ++
    },
    sub(item){
      item.count --
    }
  },
  computed:{
    totalPrice(){
      let total_price =0
      for (let book of this.books){
        total_price += book.price * book.count
      }
      return total_price
    }
  },
  filters: {
    showPrice(price) {
      return "￥" + price.toFixed(2)
    }
  }
})

VUE练习购物车之js

table {
  border: 1px solid #e9e9e9;
  border-collapse: collapse;
  border-spacing: 0;
}

th, td {
  padding: 8px 16px;
  border: 1px solid #e9e9e9;
  text-align: left;
}

th {
  background-color: #f7f7f7;
  color: #5c6b77;
  font-weight: 600;
}

VUE练习购物车之css

7、v-mode 双向绑定

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 
 4 <head>
 5   <meta charset="UTF-8">
 6   <title>Document</title>
 7   <link rel="stylesheet" href="style.css">
 8 </head>
 9 
10 <body>
11   <div id="app">
12     <h3>请选择您喜欢吃水果，如果下拉列表中不存在，可以手动输入</h3>
13 
14     <select id="fu" v-model="fruit" @change="chooseCore">
15       <option v-for="item in fruits">{{item}}</option>
16     </select>
17     </br>
18     <input v-model="fruit">
19     </br>
20     您选择的水果是，{{fruit}}
21   </div>
22   <script src="https://cdn.jsdelivr.net/npm/vue@2.6.13/dist/vue.js"></script>
23   <script>
24     const app = new Vue({
25       el: "#app",
26       data: {
27         fruits: ["苹果", "香蕉", "榴莲", "葡萄"],
28         fruit: "苹果"
29       },
30       methods: {
31         chooseCore() {
32           this.fruits = []
33         }
34       }
35     })
36 
37   </script>
38 </body>
39 
40 </html>

selectfruits.html

修饰符（延时请求、数字校验、去左右空格）

            <div id="app9">
            <input v-model.number.trim.lazy="num1" />
            +
            <input v-model.number.trim.lazy="num2" />
            = {{sum}}
        </div>
        <script>
            new Vue({
                    el: "#app9",
                    data: {
                        num1: 0,
                        num2: 0,
                    },
                    computed: {
                        sum:function() {
                             return  this.num1  +  this.num2 ;
                        }
                    },
                    
                }
            )

修饰符（number.trim.lazy）

        </div>
        <div id="app10">
            <div ref="myRef">星</div>星
            <button v-on:click="changeColor2">变色</button>
        </div>
        <script>
            new Vue({
                    el: "#app10",
                    data: {
                        isActive: true,
                    },
                    methods: {
                        changeColor2: function() {
                            this.$refs.myRef.style.color = "red"
                        }
                    }
                }
            )
                <script>

获取Dom元素

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