这个示例是模仿官网示例样式和功能用我自己的方式写的，基本上没有看官网的源码，只参考自定义指令。让我们一步步来探讨一下。官网demo
要实现的功能
单条添加todo单条删除todo双击编辑todo单条todo已完成相应样式状态改变全部todo是已完成相应样式状态改变清除全部已完成todos待办todos数量显示所有todos，已完成todos，未完成todos筛选单条添加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},
把每条todo的对应状态都存在同一个对象当中，在操作改变todo状态的时候不会被统一处理，使得每条todo都有单独的状态。
单条删除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>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},
在每个li元素上绑定了鼠标移入和移除的事件来动态的改变每个todo的isActive，然后再使用isActive动态显示class。
双击编辑todo&&单条todo已完成
<input type="checkbox" class="checkBox" v-model="list.isChecked">//双向绑定isChecked<div 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}}</div><input type="text" class="content_todoList_main main_input" v-model="list.value" //双向绑定可输入valuev-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() } }}
通过每个todo里的isEditing属性控制show和是否可编辑两个状态，双击div之后改变当前todo的isEditing为true，从而显示为input，input失去焦点之后再通过blur事件改为false。
通过todo的idChecked来控制是否已完成，从而动态改变样式。
全部todos已完成
<span class="icon-down el-icon-arrow-down" //使用element库做向下箭头iconv-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)}
待办todos数量显示
<div 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</div><div class="data_times" v-show="times > 0"><span>{{times}}</span>  items left</div>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 }},
使用了计算属性对todoLists计算，用for循环刷选出idChecked为true的累加，最后返回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></div><div 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></div>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},
如果待办todos的times小于todoLists长度，就证明有已完成的todo，就可以显示“clear completed”，如果相等就说明没有已完成的todo。
三种状态筛选
所有todos，已完成todos，未完成todos筛选
<li class="content_todoList" v-show="defaultShow || (whichShow?list.isChecked:!list.isChecked)"><div 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></div>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 }},
我这里是同时if条件句判断操作，有点麻烦，目前还没有想出来其他方案。在li元素使用三元运算符和或运算符进行操作显示不同状态的todos。
完整代码
<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><body> <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> item left </div> <div class="data_times" v-show="times > 0"> <span>{{times}}</span> items left </div> <div 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> </div> <div 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> </div> <div 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> </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>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。
