這次帶給大家Vue的todoMVC使用詳解，Vue的todoMVC使用注意事項有哪些，以下就是實戰案例，一起來看一下。
這個範例是模仿官網範例樣式和功能用我自己的方式寫的，基本上沒有看官網的源碼，只參考自訂指令。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已完成對應樣式狀態改變
全部todo是已完成對應樣式狀態改變
清除全部已完成todos
#待辦事項todos數量顯示
所有todos，已完成todos，未完成todos篩選
#單條添加todo
<input type="text" class="todos_add" placeholder="What needs to be done?"
@keyup.enter="addTodo($event.target)" //绑定enter事件
ref="currentInput">//操作input元素使enter一下之后清空输入框内容
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data() {//一些初始化数据
return {
todolists: [],
dataStatus: ["All", "Active", "Completed"],
dataStatusIndex: 0,
whichShow: true,
defaultShow: true
}
},
addTodo(e) { //添加todo
var val = e.value
if (val === "") {return} //如果输入内容为空则立即返回
this.todoLists = this.todoLists.concat({//使用concat这个api添加todo
value: val, //输入内容
isEditing: false, //是否在编辑状态
isActive: false, //删除X图标是否激活
isChecked: false //是否已完成
})
this.$refs.currentInput.value = "" //按下enter添加todo之后把输入框value清零
window.localStorage.setItem("content",JSON.stringify(this.todoLists))//使用localStorage以JSON格式存储数据
},登入後複製
#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，使得每個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" //鼠标移入todo改变对应todo的isActive状态
@mouseleave="list.isActive=false" //鼠标移出todo改变对应todo的isActive状态
<span class="el-icon-close content_todoList_delete"
:class="{show: list.isActive}" //动态绑定class使鼠标移动到某一todo显示X图标
@click="deleteTodo(index)"> //绑定删除单条todo事件
</span>
</li>登入後複製
deleteTodo(index) { //删除单条todo
this.todoLists.splice(index, 1)//使用splice的api
window.localStorage.setItem("content",JSON.stringify(todoLists)) //以JSON格式存储数据//localStorage存储数据
},登入後複製
雙擊編輯todo&&單條todo已完成
<input type="checkbox" class="checkBox"
v-model="list.isChecked">//双向绑定isChecked
<p class="content_todoList_main"
@dblclick="toEdit(list)" //双击事件
v-show="!list.isEditing" //切换元素
:class="{deleted:list.isChecked}"> //动态绑定class该表已完成todo样式
{{list.value}}
</p>
<input type="text" class="content_todoList_main main_input"
v-model="list.value" //双向绑定可输入value
v-show="list.isEditing" //切换元素
v-todo-focus="list.value" //自定义指令，双击之后自动focus对焦
@blur="unEdit(list)"> //绑定blur失去焦点事件登入後複製
methods: {
toEdit(obj) { //使添加的todothing可编辑
obj.isEditing = true
},
unEdit(obj) { //使添加的todothing不可编辑
obj.isEditing = false
},
}
directives: { //自定义focus指令,需要一个binding参数做判断
"todo-focus": function (el, binding) {
if (binding.value) {
el.focus()
}
}
}登入後複製
透過每個todo裡的isEditing屬性控制show和是否可編輯兩個狀態，雙擊p之後改變目前todo的isEditing為true，因而顯示為input，input失去焦點之後再透過blur事件改為false。
透過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
<span
class="icon-down el-icon-arrow-down" //使用element库做向下箭头icon
v-show="todoLists.length>0" //通过todoLists控制是否显示向下箭头icon
@click="selectAllTodos"></span> //全部已完成事件
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selectAllTodos() { //设置所有todo为已完成,使用map的api通过todo的isChecked属性操作
this.todoLists.map(todo => todo.isChecked = todo.isChecked ? false : true)
}登入後複製
待辦todos數量顯示
<p class="data_times" v-show="times === 0"> //times为0显示item，大于0显示items，细节注定成败
<span>{{times}}</span>  item left
</p>
<p class="data_times" v-show="times > 0">
<span>{{times}}</span>  items left</p>登入後複製
computed: {
times() { //使用计算属性计算待办todos的次数
let todoArr = this.todoLists
let times = 0
for (let i = 0; i < todoArr.length; i++) {
if (todoArr[i].isChecked === false) {
times++
}
}
return times
}
},登入後複製
使用了計算屬性對todoLists計算，用for循環刷選出idChecked為true的累加，最後回傳times。
清除全部已完成todos
<p class="data_clearTodos"
@click="clearTodos"
v-show="times < todoLists.length"> //如果待办事件次数小于总todoLists长度就显示“clear completed”
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >clear completed</a>
</p>
<p class="data_clearTodos"
@click="clearTodos"
v-show="times === todoLists.length"> //如果待办事件次数等于总todoLists长度就显示“clear completed”
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ></a>
</p>
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clearTodos() { //清空已完成的todoLists，使用filter的api进行筛选
this.todoLists = this.todoLists.filter(todo => todo.isChecked === false)
window.localStorage.setItem("content",JSON.stringify(this.todoLists)) //以json格式存储数据
},登入後複製
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”，如果相等就表示沒有已完成的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)">
<p class="data_status">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow"
:class="{active: index === dataStatusIndex}" //动态class实现tab切换
v-for="(item ,index) in dataStatus" v-for循环
@click="switchStatus(index)" //切换不同tab显示内容
:key="index">
{{item}}
</a>
</p>登入後複製
switchStatus(index) { //通过if条件判断操作
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
}
},登入後複製
我這裡是同時if條件句判斷操作，有點麻煩，目前還沒想出來其他方案。在li元素使用
三元運算符和或運算子進行操作顯示不同狀態的todos。
完整程式碼
<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>登入後複製
<body>
<p id="app">
<header class="header">todos</header>
<p 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">
<p class="content_todoList_main" @dblclick="toEdit(list)" v-show="!list.isEditing" :class="{deleted:list.isChecked}">
{{list.value}}
</p>
<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>
<p class="data" v-show="todoLists.length>0">
<p class="data_times" v-show="times === 0">
<span>{{times}}</span> item left
</p>
<p class="data_times" v-show="times > 0">
<span>{{times}}</span> items left
</p>
<p class="data_status">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" :class="{active:index === dataStatusIndex}" v-for="(item,index) in dataStatus" @click="switchStatus(index)" :key="index">
{{item}}
</a>
</p>
<p class="data_clearTodos" @click="clearTodos" v-show="times < todoLists.length">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >clear completed</a>
</p>
<p class="data_clearTodos" @click="clearTodos" v-show="times === todoLists.length">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ></a>
</p>
</p>
</p>
</p>
</body>
<script>
let vm = new Vue({
el: "#app",
data() {
return {
todoLists: [],
dataStatus: ["All", "Active", "Completed"],
dataStatusIndex: 0,
whichShow: true,
defaultShow: true
}
},
computed: {
times() { //使用计算属性计算待办todos的次数
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) { //使添加的todo可编辑
obj.isEditing = true
},
unEdit(obj) { //使添加的todo不可编辑
obj.isEditing = false
},
addTodo(e) { //添加todo
var val = e.value
if (val === "") {
return
} //如果输入内容为空则立即返回
this.todoLists = this.todoLists.concat({ //使用concat这个api添加todo
value: val, //输入内容
isEditing: false, //是否在编辑状态
isActive: false, //删除X图标是否激活
isChecked: false //是否已完成
})
this.$refs.currentInput.value = "" //按下enter添加todo之后把输入框value清零
window.localStorage.setItem("content", JSON.stringify(this.todoLists)) //使用localStorage以JSON格式存储数据
},
deleteTodo(index) { //删除todo
this.todoLists.splice(index, 1)
window.localStorage.setItem("content", JSON.stringify(this.todoLists)) //以json格式存储数据
},
switchStatus(index) { //试下下方三个状态切换，略麻烦
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格式存储数据
},
selectAllTodos() { //设置所有todo为已完成
this.todoLists.map(todo => todo.isChecked = todo.isChecked ? false : true)
}
},
directives: { //自定义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) || [] //因为todoLists初始值是null,使用或运算符，如果为null设为空数组
}
})
</script>登入後複製
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