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618 lines
17 KiB
Markdown
618 lines
17 KiB
Markdown
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---
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title: 05-Vue的举例:列表功能
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publish: true
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---
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<ArticleTopAd></ArticleTopAd>
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## 列表功能举例
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### 步骤 1:列表功能
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完整的代码如下:
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```html
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta http-equiv="X-UA-Compatible" content="ie=edge">
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<title>Document</title>
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<style>
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.table {
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width: 800px;
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margin: 20px auto;
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border-collapse: collapse; /*这一行,不能少:表格的两边框合并为一条*/
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}
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.table th {
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background: #0094ff;
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color: white;
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font-size: 16px;
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border: 1px solid black;
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padding: 5px;
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}
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.table tr td {
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text-align: center;
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font-size: 16px;
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padding: 5px;
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border: 1px solid black;
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}
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</style>
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<script src="vue2.5.16.js"></script>
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</head>
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<body>
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<div id="app">
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<table class="table">
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<th>编号</th>
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<th>名称</th>
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<th>创建时间</th>
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<th>操作</th>
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<tr v-for="item in list">
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<td>{{item.id}}</td>
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<td>{{item.name}}</td>
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<td>{{item.ctime}}</td>
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<td><a href="#">删除</a></td>
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</tr>
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</table>
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</div>
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</body>
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<script>
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var vm = new Vue({
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el: '#app',
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data: {
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list: [{id: 1, name: '奔驰', ctime: new Date}, {id: 2, name: '大众', ctime: new Date}]
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}
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})
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</script>
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</html>
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```
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**代码分析**:数据是存放在data的list中的,将data中的数据通过`v-for`遍历给表格。
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上方代码运行的效果:
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![](http://img.smyhvae.com/20180401_1517.png)
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### 步骤 2:无数据时,增加提示
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如果list中没有数据,那么表格中就会只显示表头`<th>`,这样显然不太好看。
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为此,我们需要增加一个`v-if`判断:当数据为空时,显示提示。如下:
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```html
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<tr v-show="list.length == 0">
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<td colspan="4">列表无数据</td>
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</tr>
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```
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代码解释:`colspan="4"`指的是让当前这个`<td>`横跨4个单元格的位置。如下:
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![](http://img.smyhvae.com/20180401_1535.png)
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### 步骤 3:item的添加
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具体实现步骤如下:
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(1)用户填写的数据单独存放在data属性里,并采用`v-model`进行双向绑定。
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(2)用户把数据填好后,点击add按钮。此时需要增加一个点击事件的方法,将data中的数据放到list中(同时,清空文本框中的内容)。
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(3)将数据展示出来。`v-for`有个特点:当list数组发生改变后,vue.js就会自动调用`v-for`重新将数据生成,这样的话,就实现了数据的自动刷新。
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完整的代码如下:
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```html
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta http-equiv="X-UA-Compatible" content="ie=edge">
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<title>Document</title>
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<style>
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.table {
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width: 800px;
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margin: 20px auto;
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border-collapse: collapse; /*这一行,不能少:表格的两边框合并为一条*/
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}
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.table th {
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background: #0094ff;
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color: white;
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font-size: 16px;
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border: 1px solid black;
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padding: 5px;
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}
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.table tr td {
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text-align: center;
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font-size: 16px;
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padding: 5px;
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border: 1px solid black;
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}
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.form {
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width: 800px;
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margin: 20px auto;
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}
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.form button {
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margin-left: 10px;
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}
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</style>
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<script src="vue2.5.16.js"></script>
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</head>
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<body>
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<div id="app">
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<div class="form">
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编号:<input type="text" v-model="formData.id">
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名称:<input type="text" v-model="formData.name">
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<button v-on:click="addData">添加</button>
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</div>
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<table class="table">
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<th>编号</th>
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<th>名称</th>
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<th>创建时间</th>
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<th>操作</th>
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<tr v-show="list.length == 0">
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<td colspan="4">列表无数据</td>
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</tr>
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<tr v-for="item in list">
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<td>{{item.id}}</td>
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<td>{{item.name}}</td>
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<td>{{item.ctime}}</td>
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<td><a href="#">删除</a></td>
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</tr>
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</table>
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</div>
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</body>
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<script>
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var vm = new Vue({
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el: '#app',
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data: {
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list: [{id: 1, name: '奔驰', ctime: new Date}, {id: 2, name: '大众', ctime: new Date}],
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//用户添加的数据
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formData: {
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id: 0,
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name: ""
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}
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},
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methods: {
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addData: function () {
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//将数据追加到list中
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var p = {id: this.formData.id, name: this.formData.name, ctime: new Date()};
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this.list.push(p);
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//清空页面上的文本框中的数据
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this.formData.id = 0;
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this.formData.name = '';
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}
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}
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});
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</script>
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</html>
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```
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### 步骤 4:item的删除
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html部分:
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```html
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<!--绑定delete事件,根据括号里的参数进行删除-->
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<td><a href="#" v-on:click="delData(item.id)">删除</a></td>
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```
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js部分:
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```javascript
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delData: function (id) {
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// 0 提醒用户是否要删除数据
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if (!confirm('是否要删除数据?')) {
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//当用户点击的取消按钮的时候,应该阻断这个方法中的后面代码的继续执行
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return;
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}
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// 1 调用list.findIndex()方法根据传入的id获取到这个要删除数据的索引值(在数组中的索引值)
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var index = this.list.findIndex(function (item) {
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return item.id == id
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});
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// 2.0 调用方法:list.splice(待删除的索引, 删除的元素个数)
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this.list.splice(index, 1);
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}
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```
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代码解释:`find()`和`findIndex()`是ES6中为数组新增的函数。详细解释如下:
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```javascript
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// 根据id得到下标
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// 默认去遍历list集合,将集合中的每个元素传入到function的item里,
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var index = this.list.findIndex(function(item){
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//根据item中的id属性去匹配传进来的id
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//如果是则返回true ;否返回false,继续下面的一条数据的遍历,以此类推
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return item.id ==id; //如果返回true,那么findIndex方法会将这个item对应的index
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});
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```
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也就是说,我们是根据 item.id 找到这个 item 是属于list 数组中的哪个index索引。找到了index,就可以根据index来删除数组中的那个元素了。
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当item被删除后,v-for会被自动调用,进而自动更新view。
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完整版代码:
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```html
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta http-equiv="X-UA-Compatible" content="ie=edge">
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<title>Document</title>
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<style>
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.table {
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width: 800px;
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margin: 20px auto;
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border-collapse: collapse; /*这一行,不能少:表格的两边框合并为一条*/
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}
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.table th {
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background: #0094ff;
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color: white;
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font-size: 16px;
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border: 1px solid black;
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padding: 5px;
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}
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.table tr td {
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text-align: center;
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font-size: 16px;
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padding: 5px;
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border: 1px solid black;
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}
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.form {
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width: 800px;
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margin: 20px auto;
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}
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.form button {
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margin-left: 10px;
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}
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</style>
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<script src="vue2.5.16.js"></script>
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</head>
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<body>
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<div id="app">
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<div class="form">
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编号:
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<input type="text" v-model="formData.id"> 名称:
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<input type="text" v-model="formData.name">
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<button v-on:click="addData">添加</button>
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</div>
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<table class="table">
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<th>编号</th>
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<th>名称</th>
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<th>创建时间</th>
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<th>操作</th>
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<tr v-show="list.length == 0">
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<td colspan="4">列表无数据</td>
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</tr>
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<tr v-for="item in list">
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<td>{{item.id}}</td>
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<td>{{item.name}}</td>
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<td>{{item.ctime}}</td>
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<!--绑定delete事件,根据括号里的参数进行删除-->
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<td>
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<a href="#" v-on:click="delData(item.id)">删除</a>
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</td>
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</tr>
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</table>
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</div>
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</body>
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<script>
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var vm = new Vue({
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el: '#app',
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data: {
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list: [{ id: 1, name: '奔驰', ctime: new Date }, { id: 2, name: '大众', ctime: new Date }],
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//用户添加的数据
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formData: {
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id: 0,
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name: ""
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}
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},
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methods: {
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addData: function () {
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//将数据追加到list中
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var p = { id: this.formData.id, name: this.formData.name, ctime: new Date() };
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this.list.push(p);
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//清空页面上的文本框中的数据
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this.formData.id = 0;
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this.formData.name = '';
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}, //注意:方法之间用逗号隔开,这个逗号不要忘记了
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delData: function (id) {
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// 0 提醒用户是否要删除数据
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if (!confirm('是否要删除数据?')) {
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//当用户点击的取消按钮的时候,应该阻断这个方法中的后面代码的继续执行
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return;
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}
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// 1 调用list.findIndex()方法根据传入的id获取到这个要删除数据的索引值
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var index = this.list.findIndex(function (item) {
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return item.id == id
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});
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// 2 调用方法:list.splice(待删除的索引, 删除的元素个数)
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this.list.splice(index, 1);
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}
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}
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});
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</script>
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</html>
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```
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### 步骤 5:按条件筛选item
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现在要求实现的效果是,在搜索框输入关键字 keywords,列表中仅显示匹配出来的内容。也就是说:
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- 之前, v-for 中的数据,都是直接从 data 上的list中直接渲染过来的。
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- 现在, 我们在使用`v-for`进行遍历显示的时候,不能再遍历全部的 list 了;我们要自定义一个 search 方法,同时,把keywords作为参数,传递给 search 方法。即`v-for="item in search(keywords)"`。
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在 search(keywords) 方法中,为了获取 list 数组中匹配的item,我们可以有两种方式实现。如下。
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**方式一**:采用`forEach + indexOf()`
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```javascript
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search(keywords) { // 根据关键字,进行数据的搜索,返回匹配的item
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//实现方式一:通过 indexOf() 进行匹配。
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var newList = [];
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|||
|
this.list.forEach(item => {
|
|||
|
if (item.name.indexOf(keywords) != -1) { //只要不等于 -1,就代表匹配到了
|
|||
|
newList.push(item)
|
|||
|
}
|
|||
|
})
|
|||
|
return newList
|
|||
|
}
|
|||
|
```
|
|||
|
|
|||
|
上方代码中, 我们要注意 indexOf(str) 的用法。举例如下:
|
|||
|
|
|||
|
```javascript
|
|||
|
var str = 'smyhvae';
|
|||
|
|
|||
|
console.log(str.indexOf('s')); //打印结果:0
|
|||
|
|
|||
|
console.log(str.indexOf('')); //打印结果:0。(说明,即使去匹配空字符串,也是返回0)
|
|||
|
|
|||
|
console.log(str.indexOf('h')); //打印结果:3
|
|||
|
|
|||
|
console.log(str.indexOf('x')); //打印结果:-1 (说明,匹配不到任何字符串)
|
|||
|
```
|
|||
|
|
|||
|
上方代码中,也就是说,如果参数为空字符串,那么,每个item都能匹配到。
|
|||
|
|
|||
|
**方式二**: filter + includes()方法
|
|||
|
|
|||
|
```javascript
|
|||
|
search(keywords) { // 根据关键字,进行数据的搜索,返回匹配的item
|
|||
|
|
|||
|
var newList = this.list.filter(item => {
|
|||
|
// 注意 : ES6中,为字符串提供了一个新方法,叫做 String.prototype.includes('要包含的字符串')
|
|||
|
// 如果包含,则返回 true ,否则返回 false
|
|||
|
if (item.name.includes(keywords)) {
|
|||
|
return item
|
|||
|
}
|
|||
|
})
|
|||
|
|
|||
|
return newList
|
|||
|
}
|
|||
|
```
|
|||
|
|
|||
|
注意:forEach some filter findIndex,这些都属于数组的新方法,都会对数组中的每一项,进行遍历,执行相关的操作。这里我们采用数组中的 filter 方法,
|
|||
|
|
|||
|
总的来说,方式二的写法更优雅,因为字符串的 includes()方法确实很实用。
|
|||
|
|
|||
|
完整版代码如下:
|
|||
|
|
|||
|
```html
|
|||
|
<!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>Document</title>
|
|||
|
<style>
|
|||
|
.table {
|
|||
|
width: 800px;
|
|||
|
margin: 20px auto;
|
|||
|
border-collapse: collapse;/*这一行,不能少:表格的两边框合并为一条*/
|
|||
|
}
|
|||
|
|
|||
|
.table th {
|
|||
|
background: #0094ff;
|
|||
|
color: white;
|
|||
|
font-size: 16px;
|
|||
|
border: 1px solid black;
|
|||
|
padding: 5px;
|
|||
|
}
|
|||
|
|
|||
|
.table tr td {
|
|||
|
text-align: center;
|
|||
|
font-size: 16px;
|
|||
|
padding: 5px;
|
|||
|
border: 1px solid black;
|
|||
|
}
|
|||
|
|
|||
|
.form {
|
|||
|
width: 800px;
|
|||
|
margin: 20px auto;
|
|||
|
}
|
|||
|
|
|||
|
.form button {
|
|||
|
margin-left: 10px;
|
|||
|
}
|
|||
|
</style>
|
|||
|
|
|||
|
<script src="vue2.5.16.js"></script>
|
|||
|
</head>
|
|||
|
|
|||
|
<body>
|
|||
|
|
|||
|
<div id="app">
|
|||
|
|
|||
|
<div class="form">
|
|||
|
|
|||
|
编号:
|
|||
|
<input type="text" v-model="formData.id"> 名称:
|
|||
|
<input type="text" v-model="formData.name">
|
|||
|
|
|||
|
<button v-on:click="addData">添加</button>
|
|||
|
搜索:
|
|||
|
<input type="text" v-model="keywords">
|
|||
|
|
|||
|
</div>
|
|||
|
|
|||
|
<table class="table">
|
|||
|
<th>编号</th>
|
|||
|
<th>名称</th>
|
|||
|
<th>创建时间</th>
|
|||
|
<th>操作</th>
|
|||
|
<tr v-show="list.length == 0">
|
|||
|
<td colspan="4">列表无数据</td>
|
|||
|
</tr>
|
|||
|
<tr v-for="item in search(keywords)">
|
|||
|
<td>{{item.id}}</td>
|
|||
|
<td>{{item.name}}</td>
|
|||
|
<td>{{item.ctime}}</td>
|
|||
|
<!--绑定delete事件,根据括号里的参数进行删除-->
|
|||
|
<td>
|
|||
|
<a href="#" v-on:click="delData(item.id)">删除</a>
|
|||
|
</td>
|
|||
|
</tr>
|
|||
|
</table>
|
|||
|
</div>
|
|||
|
|
|||
|
</body>
|
|||
|
|
|||
|
<script>
|
|||
|
var vm = new Vue({
|
|||
|
el: '#app',
|
|||
|
data: {
|
|||
|
list: [{ id: 1, name: '奔驰', ctime: new Date }, { id: 2, name: '大众', ctime: new Date }],
|
|||
|
//用户添加的数据
|
|||
|
formData: {
|
|||
|
id: '',
|
|||
|
name: ""
|
|||
|
},
|
|||
|
keywords: ""
|
|||
|
},
|
|||
|
|
|||
|
methods: {
|
|||
|
addData: function () {
|
|||
|
//将数据追加到list中
|
|||
|
var p = { id: this.formData.id, name: this.formData.name, ctime: new Date() };
|
|||
|
this.list.push(p);
|
|||
|
|
|||
|
//清空页面上的文本框中的数据
|
|||
|
this.formData.id = '';
|
|||
|
this.formData.name = '';
|
|||
|
}, //注意:方法之间用逗号隔开,这个逗号不要忘记了
|
|||
|
|
|||
|
delData: function (id) {
|
|||
|
// 0 提醒用户是否要删除数据
|
|||
|
if (!confirm('是否要删除数据?')) {
|
|||
|
//当用户点击的取消按钮的时候,应该阻断这个方法中的后面代码的继续执行
|
|||
|
return;
|
|||
|
}
|
|||
|
|
|||
|
// 1 调用list.findIndex()方法根据传入的id获取到这个要删除数据的索引值
|
|||
|
var index = this.list.findIndex(function (item) {
|
|||
|
return item.id == id
|
|||
|
});
|
|||
|
|
|||
|
// 2 调用方法:list.splice(待删除的索引, 删除的元素个数)
|
|||
|
this.list.splice(index, 1);
|
|||
|
},
|
|||
|
|
|||
|
search(keywords) { // 根据关键字,进行数据的搜索,返回匹配的item
|
|||
|
|
|||
|
var newList = this.list.filter(item => {
|
|||
|
// 注意 : ES6中,为字符串提供了一个新方法,叫做 String.prototype.includes('要包含的字符串')
|
|||
|
// 如果包含,则返回 true ,否则返回 false
|
|||
|
if (item.name.includes(keywords)) {
|
|||
|
return item
|
|||
|
}
|
|||
|
})
|
|||
|
|
|||
|
return newList
|
|||
|
}
|
|||
|
}
|
|||
|
});
|
|||
|
|
|||
|
</script>
|
|||
|
|
|||
|
</html>
|
|||
|
|
|||
|
```
|
|||
|
|
|||
|
备注:在1.x 版本中可以通过filterBy指令来实现过滤,但是在2.x中已经被废弃了。
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|