Vue官網todoMVC示例
這個示例是模仿官網示例樣式和功能用我自己的方式寫的，基本上沒有看官網的原始碼，只參考自定義指令。讓我們一步步來探討一下。官網demo
要實現的功能
- 單條新增todo
- 單條刪除todo
- 雙擊編輯todo
- 單條todo已完成相應樣式狀態改變
- 全部todo是已完成相應樣式狀態改變
- 清除全部已完成todos
- 待辦todos數量顯示
- 所有todos，已完成todos，未完成todos篩選
單條新增todo
<input type="text" class="todos_add" placeholder="What needs to be done?" @keyup.enter="addTodo($event.target)" //繫結enter事件 ref="currentInput">//操作input元素使enter一下之後清空輸入框內容
data() {//一些初始化資料
return {
todolists: [],
dataStatus: ["All", "Active", "Completed"],
dataStatusIndex: 0,
whichShow: true,
defaultShow: true
}
},addTodo(e) { //新增todo var val = e.value if (val === "") {return} //如果輸入內容為空則立即返回 this.todoLists = this.todoLists.concat({//使用concat這個api新增todo value: val, //輸入內容 isEditing: false, //是否在編輯狀態 isActive: false, //刪除X圖示是否啟用 isChecked: false //是否已完成 }) this.$refs.currentInput.value = "" //按下enter新增todo之後把輸入框value清零 window.localStorage.setItem("content",JSON.stringify(this.todoLists))//使用localStorage以JSON格式儲存資料 },
把每條todo的對應狀態都存在同一個物件當中，在操作改變todo狀態的時候不會被統一處理，使得每條todo都有單獨的狀態。
單條刪除todo
<li class="content_todoList" v-for="(list,index) in todoLists" @mouseover="list.isActive = true" //滑鼠移入todo改變對應todo的isActive狀態 @mouseleave="list.isActive=false" //滑鼠移出todo改變對應todo的isActive狀態 <span class="el-icon-close content_todoList_delete" :class="{show: list.isActive}" //動態繫結class使滑鼠移動到某一todo顯示X圖示 @click="deleteTodo(index)"> //繫結刪除單條todo事件 </span> </li>
deleteTodo(index) { //刪除單條todo
this.todoLists.splice(index, 1)//使用splice的api
window.localStorage.setItem("content",JSON.stringify(todoLists)) //以JSON格式儲存資料//localStorage儲存資料
},在每個li元素上綁定了滑鼠移入和移除的事件來動態的改變每個todo的isActive，然後再使用isActive動態顯示class。
雙擊編輯todo&&單條todo已完成
```<input type="checkbox" class="checkBox"
v-model="list.isChecked">//雙向繫結isChecked
<div class="content_todoList_main"
@dblclick="toEdit(list)" //雙擊事件
v-show="!list.isEditing" //切換元素
:class="{deleted:list.isChecked}"> //動態繫結class該表已完成todo樣式
{{list.value}}
</div>
<input type="text" class="content_todoList_main main_input"
v-model="list.value" //雙向繫結可輸入value
v-show="list.isEditing" //切換元素
v-todo-focus="list.value" //自定義指令，雙擊之後自動focus對焦
@blur="unEdit(list)"> //繫結blur失去焦點事件
methods: {
toEdit(obj) { //使新增的todothing可編輯
obj.isEditing = true
},
unEdit(obj) { //使新增的todothing不可編輯
obj.isEditing = false
},}
directives: { //自定義focus指令,需要一個binding引數做判斷
"todo-focus": function (el, binding) {
if (binding.value) {
el.focus()
}
}
}
```
通過每個todo裡的isEditing屬性控制show和是否可編輯兩個狀態，雙擊div之後改變當前todo的isEditing為true，從而顯示為input，input失去焦點之後再通過blur事件改為false。
通過todo的idChecked來控制是否已完成，從而動態改變樣式。
全部todos已完成
class="icon-down el-icon-arrow-down" //使用element庫做向下箭頭icon
v-show="todoLists.length>0" //通過todoLists控制是否顯示向下箭頭icon
@click="selectAllTodos"></span> //全部已完成事件
selectAllTodos() { //設定所有todo為已完成,使用map的api通過todo的isChecked屬性操作
this.todoLists.map(todo => todo.isChecked = todo.isChecked ? false : true)
}待辦todos數量顯示
<div class="data_times" v-show="times === 0"> //times為0顯示item，大於0顯示items，細節註定成敗 <span>{{times}}</span>&nbsp item left </div> <div class="data_times" v-show="times > 0"> <span>{{times}}</span>&nbsp items left</div>
computed: {
times() { //使用計算屬性計算待辦todos的次數
let todoArr = this.todoLists
let times = 0
for (let i = 0; i < todoArr.length; i++) {
if (todoArr[i].isChecked === false) {
times++
}
}
return times
}
},使用了計算屬性對todoLists計算，用for迴圈刷選出idChecked為true的累加，最後返回times。
清除全部已完成todos
```<div class="data_clearTodos"
@click="clearTodos"
v-show="times < todoLists.length"> //如果待辦事件次數小於總todoLists長度就顯示“clear completed”
<a href="#">clear completed</a>
</div>
<div class="data_clearTodos"
@click="clearTodos"
v-show="times === todoLists.length"> //如果待辦事件次數等於總todoLists長度就顯示“clear completed”
<a href="#"></a>
</div>
clearTodos() { //清空已完成的todoLists，使用filter的api進行篩選
this.todoLists = this.todoLists.filter(todo => todo.isChecked === false)
window.localStorage.setItem("content",JSON.stringify(this.todoLists)) //以json格式儲存資料
},
```
如果待辦todos的times小於todoLists長度，就證明有已完成的todo，就可以顯示“clear completed”，如果相等就說明沒有已完成的todo。
三種狀態篩選
所有todos，已完成todos，未完成todos篩選
```<li class="content_todoList"
v-show="defaultShow || (whichShow?list.isChecked:!list.isChecked)">
<div class="data_status">
<a href="#"
:class="{active: index === dataStatusIndex}" //動態class實現tab切換
v-for="(item ,index) in dataStatus" v-for迴圈
@click="switchStatus(index)" //切換不同tab顯示內容
:key="index">
{{item}}
</a>
</div>
switchStatus(index) { //通過if條件判斷操作
this.dataStatusIndex = index
if (this.dataStatus[index] === "Active") {
this.defaultShow = false
this.whichShow = false
} else if (this.dataStatus[index] === "Completed") {
this.defaultShow = false
this.whichShow = true
} else if (this.dataStatus[index] === "All") {
this.defaultShow = true
}
},
<p>我這裡是同時if條件句判斷操作，有點麻煩，目前還沒有想出來其他方案。在<code>li</code>元素使用三元運算子和或運算子進行操作顯示不同狀態的todos。</p>
<h1>完整程式碼</h1>
<style>
* {
padding: 0;
margin: 0;
box-sizing: border-box;
}
input {
outline: none;
}
ul,
li,
ol {
list-style: none;
}
#app {
width: 800px;
height: 900px;
margin: 0 auto;
text-align: center;
background-color: rgb(245, 245, 245);
padding: 24px 0;
}
#app .header {
font-size: 48px;
}
.content {
width: 72%;
margin: 0 auto;
box-shadow: 0 3px 3px 2px rgba(0, 0, 0, 0.25);
position: relative;
}
.icon-down {
position: absolute;
font-size: 24px;
top: 16px;
left: 16px;
cursor: pointer;
}
#app .content .todos_add {
width: 100%;
height: 56px;
padding: 16px 56px;
font-size: 24px;
border: 1px solid transparent;
}
.content_todoLists {
position: relative;
z-index: 3;
}
.content_todoList {
display: flex;
flex-direction: row;
border-top: 1px solid #ccc;
font-size: 24px;
padding: 8px;
background-color: white;
align-items: center;
}
.checkBox {
width: 20px;
height: 20px;
margin-left: 10px;
}
.content_todoList_main {
flex: 1;
text-align: left;
margin-left: 16px;
font-size: 20px;
padding: 6px 0;
}
.main_input {
position: relative;
z-index: 1;
}
.content_todoList_delete {
position: absolute;
right: 16px;
color: rgb(252, 55, 55);
font-weight: 500;
display: none;
cursor: pointer;
}
.show {
display: block;
}
.deleted {
text-decoration-line: line-through;
color: #bbb;
}
.show:hover {
color: rgb(255, 0, 0);
font-weight: 700;
}
::-moz-placeholder {
color: rgb(221, 218, 218);
}
::-webkit-input-placeholder {
color: rgb(221, 218, 218);
}
:-ms-input-placeholder {
color: rgb(221, 218, 218);
}
.data {
display: flex;
justify-content: space-between;
padding: 8px;
font-size: 14px;
font-weight: 300;
color: rgb(145, 145, 145);
}
a {
text-decoration: none;
color: rgb(145, 145, 145);
}
.data_times {
width: 73px;
}
.data_clearTodos {
width: 142px;
}
.data_status a {
display: inline-block;
border: 1px solid transparent;
border-radius: 2px;
padding: 1px 4px;
margin: 0 2px;
}
.data_status a:hover {
border-color: #bbb;
}
.data_clearTodos a:hover {
text-decoration-line: underline;
}
.active {
box-shadow: 0 0 1px black;
}</style>
```
<div id="app">
<header class="header">todos</header>
<div class="content">
<span class="icon-down el-icon-arrow-down"
v-show="todoLists.length>0"
@click="selectAllTodos">
</span>
<input type="text" class="todos_add" placeholder="What needs to be done?"
@keyup.enter="addTodo($event.target)"
ref="currentInput">
<ul class="content_todoLists">
<li v-for="(list,index) in todoLists" class="content_todoList"
@mouseover="list.isActive = true"
@mouseleave="list.isActive=false"
v-show="defaultShow || (whichShow?list.isChecked:!list.isChecked)">
<input type="checkbox" class="checkBox" v-model="list.isChecked">
<div class="content_todoList_main" @dblclick="toEdit(list)" v-show="!list.isEditing" :class="{deleted:list.isChecked}">
{{list.value}}
</div>
<input type="text" class="content_todoList_main main_input"
v-model="list.value"
v-show="list.isEditing"
v-todo-focus="list.value"
@blur="unEdit(list)">
<span class="el-icon-close content_todoList_delete" :class="{show: list.isActive}" @click="deleteTodo(index)"></span>
</li>
</ul>
<div class="data" v-show="todoLists.length>0">
<div class="data_times" v-show="times === 0">
<span>{{times}}</span>&nbspitem left
</div>
<div class="data_times" v-show="times > 0">
<span>{{times}}</span>&nbspitems left
</div>
<div class="data_status">
<a href="#" :class="{active:index === dataStatusIndex}" v-for="(item,index) in dataStatus" @click="switchStatus(index)" :key="index">
{{item}}
</a>
</div>
<div class="data_clearTodos" @click="clearTodos" v-show="times < todoLists.length">
<a href="#">clear completed</a>
</div>
<div class="data_clearTodos" @click="clearTodos" v-show="times === todoLists.length">
<a href="#"></a>
</div>
</div>
</div>
</div>
</body>
<script>
let vm = new Vue({
el: "#app",
data() {
return {
todoLists: [],
dataStatus: ["All", "Active", "Completed"],
dataStatusIndex: 0,
whichShow: true,
defaultShow: true
}
},
computed: {
times() { //使用計算屬性計算待辦todos的次數
let todoArr = this.todoLists
let times = 0
for (let i = 0; i < todoArr.length; i++) {
if (todoArr[i].isChecked === false) {
times++
}
}
return times
}
},
methods: {
toEdit(obj) { //使新增的todo可編輯
obj.isEditing = true
},
unEdit(obj) { //使新增的todo不可編輯
obj.isEditing = false
},
addTodo(e) { //新增todo
var val = e.value
if (val === "") {
return
} //如果輸入內容為空則立即返回
this.todoLists = this.todoLists.concat({ //使用concat這個api新增todo
value: val, //輸入內容
isEditing: false, //是否在編輯狀態
isActive: false, //刪除X圖示是否啟用
isChecked: false //是否已完成
})
this.$refs.currentInput.value = "" //按下enter新增todo之後把輸入框value清零
window.localStorage.setItem("content", JSON.stringify(this.todoLists)) //使用localStorage以JSON格式儲存資料
},
deleteTodo(index) { //刪除todo
this.todoLists.splice(index, 1)
window.localStorage.setItem("content", JSON.stringify(this.todoLists)) //以json格式儲存資料
},
switchStatus(index) { //試下下方三個狀態切換，略麻煩
this.dataStatusIndex = index
if (this.dataStatus[index] === "Active") {
this.defaultShow = false
this.whichShow = false
} else if (this.dataStatus[index] === "Completed") {
this.defaultShow = false
this.whichShow = true
} else if (this.dataStatus[index] === "All") {
this.defaultShow = true
}
},
clearTodos() { //清空已完成的todoLists
this.todoLists = this.todoLists.filter(todo => todo.isChecked === false)
window.localStorage.setItem("content", JSON.stringify(this.todoLists)) //以json格式儲存資料
},
selectAllTodos() { //設定所有todo為已完成
this.todoLists.map(todo => todo.isChecked = todo.isChecked ? false : true)
}
},
directives: { //自定義focus指令
"todo-focus": function (el, binding) {
if (binding.value) {
el.focus()
}
}
},
created() {
let myStorage = window.localStorage.getItem('content')
this.todoLists = JSON.parse(myStorage) || [] //因為todoLists初始值是null,使用或運算子，如果為null設為空陣列
}
})
</script>原文地址：https://segmentfault.com/a/1190000013026721