vueday1

1.作用：利用表达式进行插值，渲染到页面中

三元表达式、点语法、数组对应项，方法、点语法方法

1.使用的时候需要存在，需要在data里面声明，如果没有声明会报错

2.ifelse不能用

3.不能在标签属性中使用{{}}插值

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head><body><div id="app">{{ msg }}{{ count }}</div><!-- 数据响应式：数据改变，视图自动更新 --><script src="https://cdn.jsdelivr.net/npm/vue@2.7.16/dist/vue.min.js"></script><script>const app = new Vue({el: '#app',data: {//响应式数据msg: '你好，黑马',count: 100}})//1.访问数据 实例.束胸名//2.修改数据 实例.属性名= 新值</script>
</body></html>

Vue指令

v-html：

作用：设置元素的innerHTML

语法：v-html="表达式"

v-show&&v-if

作用：控制元素显示隐藏

v-show=“表达式”

原理display：none

场景：频繁切换显示隐藏的场景

v-if

v-if(条件渲染)

语法：v-if=“表达式”

原理：基于条件判断，是否创建或者移除元素节点

场景：要么隐藏，要么显示

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><style>.box {width: 200px;height: 100px;line-height: 100px;margin: 10px;border: 3px solid #000;text-align: center;border-radius: 5px;box-shadow: 2px 2px 2px #ccc;}</style>
</head><body><div id="app"><!-- 简单的显示隐藏 display：none 适用于频繁切换的场景：比如小米的购物车 --><div v-show="flag" class="box">我是v-show控制的盒子</div><!-- 基于条件的判断，是否穿件或者移除元素节点：要么显示，要么隐藏，不频繁切换的场景你入提醒你登录，你叉掉之后就没有了，登录完后就用v-if --><div v-if="flag" class="box">我是v-if控制的盒子</div></div><script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script><script>const app = new Vue({el: '#app',data: {flag: false}})</script>
</body></html>

07-Vue 指令-v-else、v-else-if

<!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"><p v-if="gender === 1">性别：♂ 男</p><p v-else>性别：♀ 女</p><hr><p v-if="score>=90">成绩评定A：奖励电脑一台</p><p v-else-if="score>=80">成绩评定B：奖励周末郊游</p><p v-else-if="score>=70">成绩评定C：奖励零食礼包</p><p v-else>成绩评定D：惩罚一周不能玩手机</p></div><script src="../vuejs/vue.js"></script><script>const app = new Vue({el: '#app',data: {gender: 2,score: 89}})</script></body></html>

08-v-on-内联语句

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head><body><div id="app"><button @mouseover="count--">-</button><span>{{ count }}</span><button @mouseover="count++">+</button></div>
</body>
<script src="../vuejs/vue.js"></script>
<script>const app = new Vue({el: '#app',data: {count: 100},// method提供方法method: {}})
</script></html>

09-v-on配置methods函数

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head><body><div id="app"><button @click="fn">切换显示隐藏</button><h1 v-show="isShow">黑马程序员</h1></div><script src="../vuejs/vue.js"></script><script>const app = new Vue({el: '#app',data: {isShow: 'true'},// methods提供方法methods: {fn () {this.isShow = !this.isShow;// console.log(`执行了fn`, !app.isShow);}}})</script></body></html>

09-Vue 指令-v-on-参数传递

<!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 {border: 3px solid #000000;border-radius: 10px;padding: 20px;margin: 20px;width: 200px;}h3 {margin: 10px 0 20px 0;}p {margin: 20px;}</style>
</head><body><div id="app"><div class="box"><h3>小黑自动售货机</h3><button @click="buy(5)">可乐5元</button><button @click="buy(10)">咖啡10元</button><button @click="buy(8)">牛奶8元</button></div><p>银行卡余额：{{ money }}元</p></div><script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script><script>const app = new Vue({el: '#app',data: {money: 100},methods: {buy (price) {this.money -= price}}})</script>
</body></html>

10-v-bind

作用：动态的设施html的标签属性-> src url title

语法：v-bind：属性名=“表达式”

<!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"><img v-bind:src="imgUrl" v-bind:title="msg" alt=""><img v-bind:src="imgUrl" v-bind:title="msg" alt=""></div><script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script><script>const app = new Vue({el: '#app',data: {imgUrl: './imgs/10-02.png',msg: 'hello 波仔'}})</script>
</body></html>

v-for

作用：基于数据循环-》数组，对象，数字

语法:v-for ="(item,index) in 数组"

item每一项，index下标

<!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>小黑水果店</h3><ul><li v-for="(item,index) in list">{{ item }} - {{ index }}</li></ul><ul><li v-for="(item) in list">{{ item }}</li></ul></div><script src="./vue.js"></script><script>const app = new Vue({el: '#app',data: {list: ['西瓜', '苹果', '鸭梨']}})</script>
</body></html>

13-案例-波仔的书架

<!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>小黑的书架</h3><ul><li v-for="(item,index) in booksList"><span>{{ item.name }}</span><span>{{ item.author }}</span><button @click="del(item.id)">删除</button></li></ul></div><script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script><script>const app = new Vue({el: '#app',data: {booksList: [{ id: 1, name: '《红楼梦》', author: '曹雪芹' },{ id: 2, name: '《西游记》', author: '吴承恩' },{ id: 3, name: '《水浒传》', author: '施耐庵' },{ id: 4, name: '《三国演义》', author: '罗贯中' }]},methods: {del (id) {this.booksList = this.booksList.filter(item => item.id !== id)}}})</script>
</body></html>

15-Vue指令-v-model

<!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">账户：<input type="text" v-model="username"> <br><br>密码：<input type="password" v-model="password"> <br><br><button @click="login">登录</button><button @click="reset">重置</button></div><script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script><script>const app = new Vue({el: '#app',data: {username: '',password: ''},methods: {login () {console.log(this.username, this.password)},reset () {this.username = ''this.password = ''}}})</script>
</body></html>

00-小黑记事本

<!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/index.css" /><title>记事本</title>
</head><body><!-- 1.列表渲染2.删除功能3.添加功能4.底部统计和清空 --><!-- 主体区域 --><section id="app"><!-- 输入框 --><header class="header"><h1>小黑记事本</h1><input v-model="todoName" placeholder="请输入任务" class="new-todo" /><button @click="add" class="add">添加任务</button></header><!-- 列表区域 --><section class="main"><ul class="todo-list"><li class="todo" v-for="(item,index) in list" :key="item.id"><div class="view"><span class="index">{{ index + 1 }}</span> <label>{{item.name}}</label><button class="destroy" @click="del(item.id)"></button></div></li></ul></section><!-- 统计和清空 --><footer class="footer" v-show="list.length > 0"><!-- 统计 --><span class="todo-count">合 计:<strong> {{ list.length }}</strong></span><!-- 清空 --><button @click="clear" class="clear-completed">清空任务</button></footer></section><!-- 底部 --><script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script><script>const app = new Vue({el: '#app',data: {todoName: '',list: [{ id: 1, name: '跑步一公里' },{ id: 2, name: '游泳一百米' },{ id: 3, name: '瑜伽两小时' }]},methods: {del (id) {this.list = this.list.filter(item => item.id !== id)// this.list.splice(index, 1)},add () {if (this.todoName.trim() === '') {alert('Please enter a name')return}this.list.unshift({id: +new Date(),name: this.todoName})this.todoName = ''},clear () {this.list = []}}})</script>
</body></html>

html,
body {margin: 0;padding: 0;
}
body {background: #fff;
}
button {margin: 0;padding: 0;border: 0;background: none;font-size: 100%;vertical-align: baseline;font-family: inherit;font-weight: inherit;color: inherit;-webkit-appearance: none;appearance: none;-webkit-font-smoothing: antialiased;-moz-osx-font-smoothing: grayscale;
}body {font: 14px 'Helvetica Neue', Helvetica, Arial, sans-serif;line-height: 1.4em;background: #f5f5f5;color: #4d4d4d;min-width: 230px;max-width: 550px;margin: 0 auto;-webkit-font-smoothing: antialiased;-moz-osx-font-smoothing: grayscale;font-weight: 300;
}:focus {outline: 0;
}.hidden {display: none;
}#app {background: #fff;margin: 180px 0 40px 0;padding: 15px;position: relative;box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.2), 0 25px 50px 0 rgba(0, 0, 0, 0.1);
}
#app .header input {border: 2px solid rgba(175, 47, 47, 0.8);border-radius: 10px;
}
#app .add {position: absolute;right: 15px;top: 15px;height: 68px;width: 140px;text-align: center;background-color: rgba(175, 47, 47, 0.8);color: #fff;cursor: pointer;font-size: 18px;border-radius: 0 10px 10px 0;
}#app input::-webkit-input-placeholder {font-style: italic;font-weight: 300;color: #e6e6e6;
}#app input::-moz-placeholder {font-style: italic;font-weight: 300;color: #e6e6e6;
}#app input::input-placeholder {font-style: italic;font-weight: 300;color: gray;
}#app h1 {position: absolute;top: -120px;width: 100%;left: 50%;transform: translateX(-50%);font-size: 60px;font-weight: 100;text-align: center;color: rgba(175, 47, 47, 0.8);-webkit-text-rendering: optimizeLegibility;-moz-text-rendering: optimizeLegibility;text-rendering: optimizeLegibility;
}.new-todo,
.edit {position: relative;margin: 0;width: 100%;font-size: 24px;font-family: inherit;font-weight: inherit;line-height: 1.4em;border: 0;color: inherit;padding: 6px;box-shadow: inset 0 -1px 5px 0 rgba(0, 0, 0, 0.2);box-sizing: border-box;-webkit-font-smoothing: antialiased;-moz-osx-font-smoothing: grayscale;
}.new-todo {padding: 16px;border: none;background: rgba(0, 0, 0, 0.003);box-shadow: inset 0 -2px 1px rgba(0, 0, 0, 0.03);
}.main {position: relative;z-index: 2;
}.todo-list {margin: 0;padding: 0;list-style: none;overflow: hidden;
}.todo-list li {position: relative;font-size: 24px;height: 60px;box-sizing: border-box;border-bottom: 1px solid #e6e6e6;
}.todo-list li:last-child {border-bottom: none;
}.todo-list .view .index {position: absolute;color: gray;left: 10px;top: 20px;font-size: 22px;
}.todo-list li .toggle {text-align: center;width: 40px;/* auto, since non-WebKit browsers doesn't support input styling */height: auto;position: absolute;top: 0;bottom: 0;margin: auto 0;border: none; /* Mobile Safari */-webkit-appearance: none;appearance: none;
}.todo-list li .toggle {opacity: 0;
}.todo-list li .toggle + label {/*Firefox requires `#` to be escaped - https://bugzilla.mozilla.org/show_bug.cgi?id=922433IE and Edge requires *everything* to be escaped to render, so we do that instead of just the `#` - https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/7157459/*/background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23ededed%22%20stroke-width%3D%223%22/%3E%3C/svg%3E');background-repeat: no-repeat;background-position: center left;
}.todo-list li .toggle:checked + label {background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23bddad5%22%20stroke-width%3D%223%22/%3E%3Cpath%20fill%3D%22%235dc2af%22%20d%3D%22M72%2025L42%2071%2027%2056l-4%204%2020%2020%2034-52z%22/%3E%3C/svg%3E');
}.todo-list li label {word-break: break-all;padding: 15px 15px 15px 60px;display: block;line-height: 1.2;transition: color 0.4s;
}.todo-list li.completed label {color: #d9d9d9;text-decoration: line-through;
}.todo-list li .destroy {display: none;position: absolute;top: 0;right: 10px;bottom: 0;width: 40px;height: 40px;margin: auto 0;font-size: 30px;color: #cc9a9a;margin-bottom: 11px;transition: color 0.2s ease-out;
}.todo-list li .destroy:hover {color: #af5b5e;
}.todo-list li .destroy:after {content: '×';
}.todo-list li:hover .destroy {display: block;
}.todo-list li .edit {display: none;
}.todo-list li.editing:last-child {margin-bottom: -1px;
}.footer {color: #777;padding: 10px 15px;height: 20px;text-align: center;border-top: 1px solid #e6e6e6;
}.footer:before {content: '';position: absolute;right: 0;bottom: 0;left: 0;height: 50px;overflow: hidden;box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2), 0 8px 0 -3px #f6f6f6,0 9px 1px -3px rgba(0, 0, 0, 0.2), 0 16px 0 -6px #f6f6f6,0 17px 2px -6px rgba(0, 0, 0, 0.2);
}.todo-count {float: left;text-align: left;
}.todo-count strong {font-weight: 300;
}.filters {margin: 0;padding: 0;list-style: none;position: absolute;right: 0;left: 0;
}.filters li {display: inline;
}.filters li a {color: inherit;margin: 3px;padding: 3px 7px;text-decoration: none;border: 1px solid transparent;border-radius: 3px;
}.filters li a:hover {border-color: rgba(175, 47, 47, 0.1);
}.filters li a.selected {border-color: rgba(175, 47, 47, 0.2);
}.clear-completed,
html .clear-completed:active {float: right;position: relative;line-height: 20px;text-decoration: none;cursor: pointer;
}.clear-completed:hover {text-decoration: underline;
}.info {margin: 50px auto 0;color: #bfbfbf;font-size: 15px;text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);text-align: center;
}.info p {line-height: 1;
}.info a {color: inherit;text-decoration: none;font-weight: 400;
}.info a:hover {text-decoration: underline;
}/*Hack to remove background from Mobile Safari.Can't use it globally since it destroys checkboxes in Firefox
*/
@media screen and (-webkit-min-device-pixel-ratio: 0) {.toggle-all,.todo-list li .toggle {background: none;}.todo-list li .toggle {height: 40px;}
}@media (max-width: 430px) {.footer {height: 50px;}.filters {bottom: 10px;}
}