Vue组件
组件分类
全局组件:在任意组件中都能使用
局部组件:只能在当前组件中使用
定义全局组件
Vue.component('child', {
template: `
<div>
<button>后退</button>
<span style="font-size: 40px">首页--{{ name }}</span>
<button @click="handleFor">前进</button>
<lqz1></lqz1>
</div>`,// 里面写html内容,必须包在一个标签中
data() { // data必须是方法,返回对象
return {
name: '彭于晏',
t: null
}
},
methods: {
handleFor() {
this.name = 'lqz'
}
},
components: {
'lqz1': {
template: `
<div>
<h1>局部组件---{{ age }}</h1>
</div>`,
data() {
return {
age: 19
}
}
},
}
})
定义局部组件
var foo={
template: `
<div>
<h1>局部组件---{{ age }}</h1>
</div>`,
data() {
return {
age: 19
}
}
}
var vm = new Vue({
...
components: {
foo
}
})
组件其它
根组件就是我们new的Vue()实例,用来管理div
我们自己再定义的全局和局部都是组件,组件有自己的html、css、js、数据、事件等
在组件中this代指的是当前组件
组件与组件之间的data是无法共享的,data是一个函数,需要有返回值
组件间通信
父传子
由于组件间的数据不共享,当我们需要数据传递时就需要使用一些其他的方法
从父组件向子组件传递数据我们使用自定义属性方式
注意事项
组建中定义的变量名不能用驼峰体
父组件中的变量名不能与子组件中的变量名冲突
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<h1>父组件</h1>
<child :age="age" myname="周润发"></child> <!--引号中的age为变量-->
<child :age="19"></child> <!--引号中的19本质上是js表达式-->
<child age="age"></child> <!--引号中的age是字符串-->
</div>
</body>
<script>
var child = {
template:`
<div>
<button>后退</button>
首页--->名字:{{ myname }}--->年龄:{{ age }}
<button>前进</button>
</div>`,
data(){
return {
myname: 'zyg'
}
},
props: {age: Number, myname: String} // 用props接收父组件传过来的数据
}
var vm = new Vue({
el: '.app',
data: {
age: 19
},
components: { // 注册子组件
child
}
})
</script>
</html>
子传父
通过自定义事件来实现子组件的数据传递给父组件
执行流程
父组件与子组件绑定同一个自定义的事件
this.$emit('myevent', this.mytext) 写在子组件的自定义事件中,子组件的自定义事件被触发,父组件的自定义事件绑定的函数也会执行,并接受从子组件传过来的参数
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<p>子组件传递过来的数据: {{mytext}}</p>
<child @myevent="handleEvent"></child>
</div>
</body>
<script>
var child = {
template: `
<div>
<input type="text" v-model="mytext">
<button @click="handleSend">点我传递</button>
</div>
`,
data() {
return {
mytext: ''
}
},
methods: {
handleSend() {
// 子组件中,触发了自定义事件的执行,会执行父组件自定义事件绑定的函数,有多少参数就传多少参数
this.$emit('myevent', this.mytext)
}
}
}
var vm = new Vue({
el: '.app',
data: {
mytext: ''
},
methods: {
handleEvent(mytext) {
this.mytext = mytext
}
},
components: { // 注册组件
child
}
})
</script>
</html>
ref属性
使用ref属性可以更方便的实现父子通信
ref属性放在普通标签上 <input type="text" ref="myinput">
通过this.$refs.myinput 拿到原生的DOM对象,在通过原生的DOM修改标签
ref属性放在组件上 <child ref="mychild"></child>
通过this.$refs.mychild 拿到组件对象,就可以通过点的方式调用组件对象中的变量、方法等
所以不需要管是父传子还是子传父,直接通过组件对象使用就行了
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<button @click="handleClick">点击</button>---{{age}}
<br>
<input type="text" ref="myinput">
<div ref="mydiv">这是div</div>
<hr>
<child ref="mychild"></child>
</div>
</body>
<script>
var child = {
template:`
<div>
<h1>名字:{{name}}---年龄:{{age}}</h1>
<button @click="handleClick">点我有惊喜</button>
</div>
`,
data(){
return {
name: 'zyg',
age: 18
}
},
methods: {
handleClick() {
alert(this.name)
}
}
}
var vm = new Vue({
el: '.app',
data: {
age: 28,
},
methods: {
handleClick() {
this.$refs.myinput.value = '周衍根' // 修改input框内容
this.age = this.$refs.mychild.age // 拿到子组件的数据
this.$refs.mychild.handleClick()
}
},
components: {
child
}
})
</script>
</html>
动态组件(以商城滑动页面为例)
不使用动态组件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<button @click="handleClick('home')">首页</button>| <button @click="handleClick('classes')">分类</button>| <button @click="handleClick('order')">订单</button>
<home v-if="chooseType=='home'"></home>
<classes v-else-if="chooseType=='classes'"></classes>
<order v-else></order>
</div>
</body>
<script>
var home = {
template: `
<div>
<h1>首页</h1>
</div>
`,
}
var classes = {
template: `
<div>
<h1>分类</h1>
</div>
`
}
var order = {
template: `
<div>
<h1>订单</h1>
</div>
`
}
var vm = new Vue({
el: '.app',
data: {
chooseType: 'home'
},
methods: {
handleClick(type) {
this.chooseType = type
}
},
components: {
home, classes, order,
}
})
</script>
</html>
使用动态组件 component标签
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<button @click="handleClick('home')">首页</button>| <button @click="handleClick('classes')">分类</button>| <button @click="handleClick('order')">订单</button>
<component :is="who"></component>
</div>
</body>
<script>
var home = {
template: `
<div>
<h1>首页</h1>
</div>
`,
}
var classes = {
template: `
<div>
<h1>分类</h1>
</div>
`
}
var order = {
template: `
<div>
<h1>订单</h1>
</div>
`
}
var vm = new Vue({
el: '.app',
data: {
who: 'home'
},
methods: {
handleClick(type) {
this.who = type
}
},
components: {
home, classes, order
}
})
</script>
</html>
保持组件不被销毁 keep-alive
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<button @click="handleClick('home')">首页</button>| <button @click="handleClick('classes')">分类</button>| <button @click="handleClick('order')">订单</button>
<keep-alive>
<component :is="who"></component>
</keep-alive>
</div>
</body>
<script>
var home = {
template: `
<div>
<h1>首页</h1>
</div>
`,
}
var classes = {
template: `
<div>
<h1>分类</h1>
</div>
`
}
var order = {
template: `
<div>
<h1>订单</h1>
</div>
`
}
var vm = new Vue({
el: '.app',
data: {
who: 'home'
},
methods: {
handleClick(type) {
this.who = type
}
},
components: {
home, classes, order
}
})
</script>
</html>
插槽
正常情况下我们编写的组件都是写死的,需要加数据的时候只能去组件中修改,扩展性较差,所以出现了插槽这个概念,我们只需要在组件中添加 <slot></slot> 就可以在body的组件标签中添加数据了
匿名插槽
匿名插槽在使用<slot></slot>时会将body的组件标签中添加的数据都拿过来,组件标签中写了几个<slot></slot>,就会拿几次
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<hr>
<home>
<div>
<img src="https://img.lesmao.vip/k/1178/T/XiuRen/5900/5900_012_ozl_2400_3600.jpg" alt="" height="200px" width="200px">
</div>
<div>
<img src="https://img.lesmao.vip/k/1178/T/YALAYI/956/956_013_ltn_4160_6240.jpg" alt="" height="200px" width="200px">
</div>
<div>
<img src="https://img.lesmao.vip/k/1178/T/XiuRen/6230/6230_015_a9g_5400_3600.jpg" alt="" height="200px" width="200px">
</div>
</home>
</div>
</body>
<script>
var home = {
template: `
<div>
<h1>主页</h1>
<slot></slot>
<h1>结束了</h1>
<slot></slot>
</div>
`
}
var vm = new Vue({
el: '.app',
data: {},
components: {
home
}
})
</script>
</html>
具名插槽
具名插槽就是给插槽和插入的内容起一个名字,只有名字对上了,才可以
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<hr>
<home>
<div slot="1">
<img src="https://img.lesmao.vip/k/1178/T/XiuRen/5900/5900_012_ozl_2400_3600.jpg" alt="" height="200px" width="200px">
</div>
<div slot="2">
<img src="https://img.lesmao.vip/k/1178/T/YALAYI/956/956_013_ltn_4160_6240.jpg" alt="" height="200px" width="200px">
</div>
<div>
<img src="https://img.lesmao.vip/k/1178/T/XiuRen/6230/6230_015_a9g_5400_3600.jpg" alt="" height="200px" width="200px">
</div>
</home>
</div>
</body>
<script>
var home = {
template: `
<div>
<h1>主页</h1>
<slot name="1"></slot>
<h1>结束了</h1>
<slot name="2"></slot>
</div>
`
}
var vm = new Vue({
el: '.app',
data: {},
components: {
home
}
})
</script>
</html>
计算属性
计算属性只有使用的变量发生变化时才重新运算
计算属性就像python中的property,可以将方法或函数伪装成属性
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.1/jquery.js"></script>
<script src="./js/vue.js"></script>
</head>
<body>
<div class="app">
<h1>首字母转大写</h1>
<input type="text" v-model="mytext">----{{newText}}
<br>
<input type="text" v-model="age">----{{age}}
</div>
</body>
<script>
var vm = new Vue({
el: '.app',
data: {
mytext: '',
age: 18
},
methods: {
getUpper() {
return this.mytext.slice(0, 1).toUpperCase() + this.mytext.slice(1)
}
},
computed: {
newText() {
return this.mytext.slice(0, 1).toUpperCase() + this.mytext.slice(1)
}
}
})
</script>
</html>
通过计算属性重写过滤案例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="./js/vue.js"></script>
</head>
<body>
<div>
<div class="app">
<h1>过滤案例</h1>
<p>请输入要搜索的内容:<input type="text" v-model="myText"></p>
<ul>
<li v-for="item in newDateList">{{item}}</li>
</ul>
</div>
</div>
</body>
<script>
var vm = new Vue({
el: '.app',
data: {
myText: '',
dataList: ['a', 'at', 'atom', 'be', 'beyond', 'cs', 'csrf'],
},
computed: {
newDateList() {
return this.dataList.filter(
item => item.indexOf(this.myText) >= 0
)
}
}
})
</script>
</html>
监听属性
<!--在data中定义的变量变化了就执行watch下面的函数-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="./js/vue.js"></script>
</head>
<body>
<div>
<div class="app">
<span @click="course_type=1">Python</span>| <span @click="course_type=2">Linux</span>
<div>
假设有很多课程,点击上面的标签可以完成过滤
</div>
</div>
</div>
</body>
<script>
var vm = new Vue({
el: '.app',
data: {
course_type: '0'
},
created() {
this.getData()
},
methods: {
getData() {
},
},
watch: {
course_type() {
console.log('我变化了')
this.getData()
}
}
})
</script>
</html>