main.js

//引入Vue
import Vue from "vue";
//引入App
import App from './App';

//关闭Vue的生产提示
Vue.config.productionTip = false;


new Vue({
    el:'#app',
    render: h => h(App)
});

App.vue

<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <MyHeader @addTodo="addTodo"/>
        <List
            :todos="todos"
            :checkTodo="checkTodo"
            :deleteTodo="deleteTodo"
        />
        <MyFooter
            :todos="todos"
            @checkAllTodo="checkAllTodo"
            @clearAllDoneTodo="clearAllDoneTodo"
        />
      </div>
    </div>
  </div>
</template>

<script>
import MyHeader from "@/components/MyHeader";
import List from "@/components/List";
import MyFooter from '@/components/MyFooter';
export default {
  name: "App",
  components:{
    List,
    MyFooter,
    MyHeader
  },
  data() {
    return {
      // todos: [
      //   {id: '001', title: '吃饭', done: false},
      //   {id: '002', title: "睡觉", done: true},
      //   {id: '003', title: '打代码', done: false}
      // ]
      todos:JSON.parse(localStorage.getItem('todos')) || []
    }
  },
  methods:{
    //添加的todo
    addTodo(todo){
      console.log('我是app组件，我收到了数据');
      this.todos.unshift(todo);
    },
    checkTodo(id){
      const todo = this.todos.find(todo => todo.id === id);
      todo.done = !todo.done;
    },
    deleteTodo(id){
      this.todos = this.todos.filter(todo => todo.id !== id);
    },
    checkAllTodo(done){
      this.todos.forEach(todo => todo.done = done);
    },
    clearAllDoneTodo(){
      this.todos = this.todos.filter(todo => !todo.done)
    }
  },
  watch:{
    //深度监视
    todos:{
      deep: true, //深度监视当我监视数组中的对象的某个属性的变化它也会产生反应
      handler(newValue) {
        //本地存储存的是key和value都是字符串
        //数据存放在本地存储中
        localStorage.setItem("todos", JSON.stringify(newValue))
      }
    },
  }
}
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}

</style>

Myheader.vue

<template>
  <div class="todo-header">
    <input type="text" placeholder="请输入你的任务名称，按回车键确认" v-model="title" @keyup.enter="add"/>
  </div>
</template>

<script>
import { nanoid } from 'nanoid';
export default {
  //注意不管是你写的data也还还是methods也好，甚至是computed计算属性也好都会出现在组件事例对象vc身上
  //属性值不能重名
  name: "MyHeader",
  data(){
    return {
      title: ''
    }
  },
  methods:{
    add(){
      //将用户的输入包装成一个todo对象
      console.log(this.title)
      if(!this.title.trim()) {
        alert('代办事项不能为空')
        return; //输入的代办事项为空则不走下面流程
      }
      const todoObj = {
        id: nanoid(),
        title: this.title,
        done:false
      }
      // console.log(todoObj);
      // this.addTodo(todoObj);
      //采用自定义事件来修改
      this.$emit('addTodo',todoObj);
      this.title = '';
    }
  },
}
</script>

<style scoped>
/*header*/
.todo-header input {
  width: 560px;
  height: 28px;
  font-size: 14px;
  border: 1px solid #ccc;
  border-radius: 4px;
  padding: 4px 7px;
}

.todo-header input:focus {
  outline: none;
  border-color: rgba(82, 168, 236, 0.8);
  box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(82, 168, 236, 0.6);
}
</style>

MyFooter.vue

<template>
  <!--隐式类型转换-->
  <div class="todo-footer" v-show="total">
    <label>
      <!--这里也可用v-model来替代，此时不需要计算属性了-->
<!--      <input type="checkbox" :checked="isAll" @change="checkAll"/>-->
      <input type="checkbox" v-model="isAll"/>
    </label>
    <span>
       <span>已完成{{ doneTotal }}</span> / 全部{{total}}
    </span>
    <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
  </div>
</template>
<script>
export default {
  name: "MyFooter",
  props: ['todos'],
  computed:{
    total(){
      return this.todos.length;
    },
    doneTotal(){
      return this.todos.reduce((todoTotal, todo) => {
        //隐士类型转换
        return todoTotal + todo.done;
      }, 0);
      // return this.todos.filter(todo => todo.done).length;
    },
    isAll:{
      get(){
        return this.total === this.doneTotal && this.doneTotal > 0; //计算属性可以通过其他的计算属性接着进行计算得到结果
      },
      set(value){
        //value注意要么为true，要么为false，因为你是把它应用在了checkbox上
        //this.checkAllTodo(value);
        //采用自定义事件来修改
        this.$emit('checkAllTodo', value);
      }
    }
  },
  methods:{
    // checkAll(e){
    //   // console.log(e.target.checked); //判断这个checkbox到底是不是全选 true全选 false全不选
    //   this.checkAllTodo(e.target.checked);
    // }
    clearAll(){
       // this.clearAllDoneTodo();
      //修改为自定义事件
      this.$emit('clearAllDoneTodo');
    }
  }
}
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>

List.vue

<template>
  <ul class="todo-main">
    <Item
        v-for="todoObj in todos"
        :key="todoObj.id"
        :todo="todoObj"
        :checkTodo="checkTodo"
        :deleteTodo="deleteTodo"
    />
  </ul>
</template>

<script>
import Item from "@/components/Item";

export default {
  name: "List",
  components: {
    Item,
  },
  props:['todos', 'checkTodo', 'deleteTodo']
}
</script>

<style scoped>
/*main*/
.todo-main {
  margin-left: 0;
  border: 1px solid #ddd;
  border-radius: 2px;
  padding: 0px;
}

.todo-empty {
  height: 40px;
  line-height: 40px;
  border: 1px solid #ddd;
  border-radius: 2px;
  padding-left: 5px;
  margin-top: 10px;
}
</style>

Item.vue

<template>
  <li>
    <label>
<!--      这里勾选和取消勾选可以使用change和click作为事件处理-->
      <input type="checkbox" :checked="todo.done" @change="handleCheck(todo.id)"/>
      <!--v-model数据的双向绑定，checkbox使用v-model来双向绑定其是否被勾选,也可以实现效果但不推荐(因为其实修改了props中的数据)-->
      <!--这里修改了从List修改过来的props,这里的不允许改是浅层次，就是如果props是一个对象则这个修改这个对象的某一个属性vue是放行的-->
      <!-- <input type="checkbox" v-model="todo.done"/>-->
      <span>{{  todo.title }}</span>
    </label>
    <button class="btn btn-danger" @click="handleDelete(todo.id)">删除</button>
  </li>
</template>

<script>
export default {
  name: "Item",
  //声明接收todo
  props: ['todo', 'checkTodo', 'deleteTodo'],
  methods:{
    handleCheck(id){
      this.checkTodo(id);
    },
    handleDelete(id){
      if(confirm(`确定删除编号为${id}的todo吗`)){
        // console.log(id);
        this.deleteTodo(id);
      }
    }
  }
}
</script>

<style scoped>
/*item*/
li {
  list-style: none;
  height: 36px;
  line-height: 36px;
  padding: 0 5px;
  border-bottom: 1px solid #ddd;
}

li label {
  float: left;
  cursor: pointer;
}

li label li input {
  vertical-align: middle;
  margin-right: 6px;
  position: relative;
  top: -1px;
}

li button {
  float: right;
  display: none;
  margin-top: 3px;
}

li:before {
  content: initial;
}

li:last-child {
  border-bottom: none;
}

li:hover{
  background: #ddd;
}

li:hover button{
  display: block;
}
</style>