上一个章节实现数据在组件之间的传递 。这一章主要是完成添加任务到任务栏、删除任务栏、统计任务完成情况。主要还是参数在各个组件之间的传递。
上一章节的链接地址：https://blog.csdn.net/weixin_43304253/article/details/126238030

1、实现的效果演示

2、需求实现的大致流程

• 添加任务到任务栏：需要考虑TheHeader中的数据怎样传入到TheList组件中
• 删除一个任务：需要拿到待删除的任务主键标识、然后在数组对象中删除（遍历的形式）
• 勾选任务：根据对象中的勾状态、取反
• 初次加载勾选已完成任务：在checkbox中 根据任务的状态展示完成情况（checked）
• 统计任务完成情况：根据对象中的任务完成状态 遍历数组。累加计算

3 、代码（这里只给出主要部分代码、详细代码请看第一章节）

3.1 App.vue(省略了样式)

<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <TheHeader :addTodo="addTodo" />
        <TheList
          :todos="todos"
          :checkTodo="checkTodo"
          :deleteTodo="deleteTodo"
        />
        <TheFooter
          :todos="todos"
          :checkAllTodo="checkAllTodo"
          :clearAllTodo="clearAllTodo"
        />
      div>
    div>
  div>
template>

<script>
import TheHeader from "./components/TheHeader";
import TheList from "./components/TheList";
import TheFooter from "./components/TheFooter.vue";

export default {
  name: "App",
  components: { TheHeader, TheList, TheFooter },
  data() {
    return {
      //由于todos是MyHeader组件和MyFooter组件都在使用，所以放在App中（状态提升）
      todos: [
        { id: "001", title: "吃饭", done: true },
        { id: "002", title: "睡觉", done: false },
        { id: "003", title: "打豆豆", done: true },
      ],
    };
  },
  methods: {
    //添加一个todo
    addTodo(todoObj) {
      this.todos.unshift(todoObj);
    },
    //勾选or取消勾选一个todo
    checkTodo(id) {
      this.todos.forEach((todo) => {
        if (todo.id === id) todo.done = !todo.done;
      });
    },

    //删除一个todo
    deleteTodo(id) {
      this.todos = this.todos.filter((todo) => todo.id !== id);
    },
    //全选or取消全选
    checkAllTodo(done) {
      this.todos.forEach((todo) => {
        todo.done = done;
      });
    },
    //清除所有已经完成的todo
    clearAllTodo() {
      this.todos = this.todos.filter((todo) => {
        return !todo.done;
      });
    },
  },
};
script>



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---

3.2 TheList.vue (省略了样式)

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

<script>
import TheItem from "./TheItem";

export default {
  name: "TheList",
  components: { TheItem },
  //声明接收App传递过来的数据，其中todos是自己用的
  props: ["todos", "checkTodo",'deleteTodo'],
};
script>
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---

3.3 TheItem.vue(样式改进：删除按钮只有停留在对应行才会显示出来)

<template>
  <li>
    <label>
      <input
        type="checkbox"
        :checked="todo.done"
        @change="handleCheck(todo.id)"
      />
      <span>{{ todo.title }}span>
    label>
    <button class="btn btn-danger" @click="handleDelete(todo.id)">删除button>
  li>
template>

<script>
export default {
  name: "MyItem",
  //声明接收todo、checkTodo、deleteTodo
  props: ["todo", "checkTodo",'deleteTodo'],

  methods: {
    //勾选or取消勾选
    handleCheck(id) {
      //通知App组件将对应的todo对象的done值取反
      this.checkTodo(id);
    },
    //删除
    handleDelete(id) {
      if (confirm("确定删除吗？")) {
        //通知App组件将对应的todo对象删除
        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-color: #ddd;
	}
	
	li:hover button{
		display: block;
	}
style>
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---

3.4 TheHeader.vue (省略了样式)

<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 {
  name: "TheHeader",
	//接收从App传递过来的addTodo
		props:['addTodo'],
  data() {
    return {
      //收集用户输入的title
      title: "",
    };
  },
  methods: {
    add() {
      //校验数据
      if (!this.title.trim()) return alert("输入不能为空");
      //将用户的输入包装成一个todo对象
      const todoObj = { id: nanoid(), title: this.title, done: false };
      //通知App组件去添加一个todo对象
      this.addTodo(todoObj);
      //清空输入
      this.title = "";
    },
  },
};
script>
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---

3.5 TheFooter.vue (省略了样式)

<template>
	<div class="todo-footer" v-show="total">
		<label>
			
			<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:'TheFooter',
		props:['todos','checkAllTodo','clearAllTodo'],
		computed: {
			//总数
			total(){
				return this.todos.length
			},
			//已完成数
			doneTotal(){
				//此处使用reduce方法做条件统计
				/* const x = this.todos.reduce((pre,current)=>{
					console.log('@',pre,current)
					return pre + (current.done ? 1 : 0)
				},0) */
				//简写
				return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0) ,0)
			},
			//控制全选框
			isAll:{
				//全选框是否勾选
				get(){
					return this.doneTotal === this.total && this.total > 0
				},
				//isAll被修改时set被调用
				set(value){
					this.checkAllTodo(value)
				}
			}
		},
		methods: {
			/* checkAll(e){
				this.checkAllTodo(e.target.checked)
			} */
			//清空所有已完成
			clearAll(){
				this.clearAllTodo()
			}
		},
	}
script>
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---

4、实现的效果

---

整理不易、欢迎白嫖党一键三连 !!! 哈哈哈哈哈哈哈哈哈。曾经我也是白嫖党