Vue 实现小小记事本

1、实现效果

用户输入后按回车，输入的内容自动保存，下方会显示记录的条数，鼠标移动到文字所在div上，会显示删除按钮，点击按钮，相应记录会被删除，下方的记录条数会相应变化，点击clear，所有记录会被删除。效果如下：

2、实现思路

• 先写出记事本的基本样式，在vue实例中的data对象里定义list数组，以及message的初始值。通过 v-model实现input标签文本和message的双向绑定。通过v-for循环遍历li标签，取出list数组中的数据。
• 给input框通过keyup.enter绑定回车事件add，直接把当前输入的值添加到list数组里，然后遍历到li标签里。
• 在li标签的button标签里添加remove事件。先传入index，通过this.list.splice(index, 1) 删除当前记录。
• 在下方的footer部分，判断是否存在记录，若不存在，则销毁标签，若存在，则添加clear事件，直接把list数组赋值为空，就可以清除所有的记录。

3、实现代码

index.css

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;

}
todoapp {
background: #fff;

margin: 180px 0 40px 0;

position: relative;

box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.2), 0 25px 50px 0 rgba(0, 0, 0, 0.1);

}
todoapp input::-webkit-input-placeholder {
font-style: italic;

font-weight: 300;

color: #e6e6e6;

}
todoapp input::-moz-placeholder {
font-style: italic;

font-weight: 300;

color: #e6e6e6;

}
todoapp input::input-placeholder {
font-style: italic;

font-weight: 300;

color: gray;

}
todoapp h1 {
position: absolute;

top: -160px;

width: 100%;

font-size: 60px;

font-weight: 100;

text-align: center;

color: rgba(175, 47, 47, .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;

border: 1px solid #999;

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;

border-top: 1px solid #e6e6e6;

}
.toggle-all {

width: 1px;

height: 1px;

border: none; /* Mobile Safari */

opacity: 0;

position: absolute;

right: 100%;

bottom: 100%;

}
.toggle-all + label {

width: 60px;

height: 34px;

font-size: 0;

position: absolute;

top: -52px;

left: -13px;

-webkit-transform: rotate(90deg);

transform: rotate(90deg);

}
.toggle-all + label:before {

content: "❯";

font-size: 22px;

color: #e6e6e6;

padding: 10px 27px 10px 27px;

}
.toggle-all:checked + label:before {

color: #737373;

}
.todo-list {

margin: 0;

padding: 0;

list-style: none;

max-height: 420px;

overflow: auto;

}
.todo-list li {

position: relative;

font-size: 24px;

border-bottom: 1px solid #ededed;

height: 60px;

box-sizing: border-box;

}
.todo-list li:last-child {

border-bottom: none;

}
.todo-list .view .index {

position: absolute;

color: gray;

left: 10px;

top: 20px;

font-size: 16px;

}
.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=922433

IE 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;

}

}

html与Vue部分

<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>记事本</title>

</head>

<link rel="stylesheet" type="text/css" href="index.css" />
<body>

<!-- 主体区域 -->

<section id="todoapp">

<!-- 输入框 -->

<header class="header">

<h1>记事本</h1>

<input autofocus="autofocus" autocomplete="off" placeholder="请输入任务" class="new-todo" v-model="message"

@keyup.enter="add" />

</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" v-show="list.length!=0">

<span class="todo-count" v-if="list.length!=0">

<strong>{{list.length}}</strong> items left

</span>

<button class="clear-completed" @click="clear">

Clear

</button>

</footer>

</section>

</body>

<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

<script>

let vm = new Vue({

el: "#todoapp",

data: {

list: ["努力向前看", "今日事，今日毕", "好读书，读好书"],

message: "please input",

},

methods: {

add() {

this.list.push(this.message)

},

remove(index) {

this.list.splice(index, 1);

},

clear() {

this.list = [];

}

}

})

</script>
</html>