v-for
v-for指令的作用是:根据数据生成列表结构
数组经常和v-for结合使用
语法是( item,index ) in 数据
item 和 index 可以结合其他指令一起使用
数组长度的更新会同步到页面上,是响应式的
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>v-for指令</title>
</head>
<body>
<div id="app">
<input type="button" value="添加数据" @click="add">
<input type="button" value="移除数据" @click="remove">
<ul>
<li v-for="(it,index) in arr">
{{ index+1 }}黑马程序员校区:{{ it }}
</li>
</ul>
<h2 v-for="item in vegetables" v-bind:title="item.name">
{{ item.name }}
</h2>
</div>
<!-- 1.开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
var app = new Vue({
el:"#app",
data:{
arr:["北京","上海","广州","深圳"],
vegetables:[
{name:"西兰花炒蛋"},
{name:"蛋炒西蓝花"}
]
},
methods: {
add:function(){
this.vegetables.push({ name:"花菜炒蛋" });
},
remove:function(){
this.vegetables.shift();
}
},
})
</script>
</body>
</html>
v-on补充
事件绑定的方法写成函数调用的形式，可以传入自定义参数
定义方法时需要定义形参来接收传入的实参
事件的后面跟上 .修饰符 可以对事件进行限制
.enter 可以限制触发的按键为回车
事件修饰符有多种
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>v-on补充</title>
</head>
<body>
<div id="app">
<input type="button" value="点击" @click="doIt(666,'老铁')">
<input type="text" @keyup.enter="sayHi">
</div>
<!-- 1.开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
var app = new Vue({
el:"#app",
methods: {
doIt:function(p1,p2){
console.log("做it");
console.log(p1);
console.log(p2);
},
sayHi:function(){
alert("吃了没");
}
},
})
</script>
</body>
</html>
v-model
v-model指令的作用是便捷的设置和获取表单元素的值
绑定的数据会和表单元素值相关联
绑定的数据←→表单元素的值 双向绑定
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>v-model指令</title>
</head>
<body>
<div id="app">
<input type="button" value="修改message" @click="setM">
<input type="text" v-model="message" @keyup.enter="getM">
<h2>{{ message }}</h2>
</div>
<!-- 开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
var app = new Vue({
el:"#app",
data:{
message:"黑马程序员"
},
methods: {
getM:function(){
alert(this.message);
},
setM:function(){
this.message ="酷丁鱼";
}
},
})
</script>
</body>
</html>
案例：记事本
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
<title>小黑记事本</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
<meta name="robots" content="noindex, nofollow" />
<meta name="googlebot" content="noindex, nofollow" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link rel="stylesheet" type="text/css" href="./css/index.css" />
</head>
<body>
<!-- 主体区域 -->
<section id="todoapp">
<!-- 输入框 -->
<header class="header">
<h1>小黑记事本</h1>
<input v-model="inputData" v-on:keyup.enter="add" autofocus="autofocus" autocomplete="off" placeholder="请输入任务"
class="new-todo" />
</header>
<!-- 列表区域 -->
<section class="main">
<ul class="todo-list">
<li class="todo" v-for="(item,index) in list ">
<div class="view">
<span class="index">{{ index+1 }}.</span>
<label>{{ item }}</label>
<button class="destroy" @click="remove(index)"></button>
</div>
</li>
</ul>
</section>
<!-- 统计和清空 -->
<footer class="footer" >
<span class="todo-count">
<strong>{{list.length}}</strong> items left
</span>
<button class="clear-completed" @click = "clear">
Clear
</button>
</footer>
</section>
<!-- 开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
var app = new Vue({
el: "#todoapp",
data:{
list:["写代码", "吃饭饭", "睡觉觉"],
inputData:"好好学习"
},
methods:{
add:function(){
this.list.push(this.inputData);
},
remove:function(index){
this.list.splice(index,1);
},
clear:function(){
this.list = [];
}
}
})
</script>
</body>
</html>
