Vue基础篇一
Vue指令
Vue的指令directive很像我们所说的自定义属性,指令时Vue模板中最常用的功能,它带有v-前缀,功能是当表达式改变的时候,相应的行为作用在DOM上.
<div id="app">
<p v-text="a"></p>
<div v-html="b"></div>
</div> <script>
const app = new Vue({
el: "#app",
data: {
a: "A",
b: `<h1>B</h1>`
}
})
</script>
v-text, v-html
<div id="app">
用户名：
<input type="text" v-model.lazy.trim="name">
手机号：
<input type="text" v-model.number="phone">
<pre>{{name}}</pre>
{{typeof phone}} <textarea name="" id="" cols="30" rows="10" v-model="article"></textarea> {{article}} <select v-model="from">
<option value="1">河北</option>
<option value="2">山西</option>
</select> <select v-model="where" multiple>
<option value="1">上地</option>
<option value="2">西二旗</option>
<option value="3">三里屯</option>
</select> {{from}}
{{where}}
</div>
<script>
// input
// textarea
// select const app = new Vue({
el: "#app",
data: {
name: "",
phone: "",
article: "这是一大段文本~~~",
from: null,
where: [] }
})
</script>
v-model
<div id="app">
<h1>展示你们的爱好</h1>
<ul>
<li v-for="hobby in hobby_list">{{hobby}}</li>
</ul>
<h1>展示你们喜欢吃的食物</h1>
<ul>
<li v-for="food in food_list">{{food.name}}它的价格是: {{food.price}}</li>
</ul>
</div>
<script>
const app = new Vue({
el: "#app",
data: {
hobby_list: ["美女", "LOL", "吃鸡"],
food_list: [
{
name: "臭豆腐",
price: 6,
},
{
name: "榴莲",
price: 100,
}
]
}
})
</script>
v-for
<style>
.active{
background-color: red;
width: 100px;
height: 100px;
}
</style>
</head>
<body>
<div id="app">
<a :href="path">@陈润</a>
<a v-bind:href="path">@陈润</a>
<div v-bind:class="{active: show}">盒子</div>
</div>
<script>
const app = new Vue({
el: "#app",
data: {
path: "http://www.baidu.com",
show: false
}
})
</script>
v-bind
<style>
.active{
background: red;
width: 100px;
height: 100px;
}
</style>
</head>
<body>
<div id="app">
<a :href="path">@chenrun</a>
<button @click="on_click">点我显示盒子的样式</button>
<div :class="{active: show}">盒子</div>
<div v-on="{mouseenter: onMouseenter, mouseleave: onMouseleave}">鼠标事件</div>
</div>
<script>
const app = new Vue({
el: "#app",
data: {
path: "http://www.baidu.com",
show: false
},
methods: {
on_click: function() {
this.show = ! this.show
},
onMouseenter: function() {
console.log("鼠标移入了")
},
onMouseleave: function() {
console.log("鼠标移除")
}
}
})
</script>
v-on
<div id="app">
<div v-if="role == 'vip'">
<h1>欢迎会员登陆</h1>
</div>
<div v-else-if="role == 'vvip'">
<h1>您的专属秘书为您服务</h1>
</div>
<div v-else>
<p>gun~~~~</p>
</div>
</div>
<script>
const app = new Vue({
el: "#app",
data: {
role: "vip",
}
})
</script>
v-if
<div id="app">
<button @click="on_click">点我</button>
<p v-show="show">Alex DSX</p> <p v-if="a == 'if_show'">DSX</p>
<p v-else>Alex</p>
</div>
<script>
const app = new Vue({
el: "#app",
data: {
show: false,
a: "if_show"
},
methods:{
on_click: function() {
this.show = ! this.show
}
}
})
//if appendChild
//show display
</script>
v-show
<div id="app">
用户名: <input type="text" v-model.lazy.trim="username"><br>
{{username}}
手机号: <input type="text" v-model.number="phone"><br>
{{phone}}
</div>
<!--//main.js-->
<script>
var app = new Vue({
el: '#app',
data: {
username: "",
phone: "",
}
})
</script>
修饰符
<style>
.active{
width: 100px;
height: 100px;
border: solid 1px red;
background: #eeeeee;
}
</style>
</head>
<body>
<div id="app">
<div class="active" v-pin.right.bottom="show"></div>
</div>
<script>
Vue.directive("pin", function(el, binding){
console.log(el);
console.log(binding);
let val = binding.value;
let positions = binding.modifiers;
if(val){
for(let key in positions){
el.style.position = "fixed";
console.log(key);
el.style[key]=0;
}
}else{
el.style.position = "static";
}
});
const app = new Vue({
el : "#app",
data: {
show: true,
}
})
</script>
自定义指令
<div id="app">
<table border="1">
<thead>
<th>学科</th>
<th>分数</th>
</thead>
<tbody>
<tr>
<td>数学</td>
<td><input type="text" v-model.number="math"></td>
</tr>
<tr>
<td>英语</td>
<td><input type="text" v-model.number="english"></td>
</tr>
<tr>
<td>物理</td>
<td><input type="text" v-model.number="physics"></td>
</tr>
<tr>
<td>总分</td>
<td>{{sum_num}}</td>
</tr>
<tr>
<td>平均分</td>
<td>{{average}}</td>
</tr>
</tbody>
</table>
</div>
<script>
const app = new Vue({
el: "#app",
data: {
math: 95,
english: 55,
physics: 100,
},
computed: {
sum_num: function(){
let total = this.math + this.english + this.physics;
return total
},
average: function(){
let ret = Math.round(this.sum_num/3);
return ret
} }
})
</script>
计算属性
Vue计算属性
我们的模板表达式非常遍历,但是逻辑复杂的时候,模板会难以维护,vue提供了计算机属性.
我们用方法也能达到效果,那么我们为什么要计算属性呢~
其实在vue中方法和计算属性达到的效果是一样的,但是计算属性时基于依赖进行缓存的.
只有依赖的数据发生改变的时候,才会重新执行计算属性的函数, 每次调用都会从缓存中拿之前算好的数据.
而方法时没调用一次,执行一次.
Vue过滤器
过滤器时在数据到达用户的最后异步进行简单的过滤处理,复杂的还要用计算属性或者方法.
<div id="app">
<div>
<p>价格展示</p>
<input type="text" v-model="price">
{{price | currency('USD')}}
</div>
<div>
<p>换算</p>
<input type="text" v-model="meters">
{{meters | meter}}
</div>
</div>
<script>
Vue.filter('currency', function (val, unit){
console.log(val);
console.log(unit);
val = val || 0;
var ret = val + unit;
return ret
});
Vue.filter('meter', function(val){
val = val || 0;
return (val/1000).toFixed(2) + "米"
});
new Vue({
el: "#app",
data: {
price: 10,
meters: 10,
}
})
</script>
过滤器