添加修改删除数据发生变化，可以用watch 监测来实现监测数据的变化
1. App.vue
<template>
<div id="root">
<div class="todo-container">
<div class="todo-wrap">
<!--传递函数 儿子给父亲传东西,父亲偷偷传递一个函数，儿子调用这个函数-->
<MyHeader :addTodo="addTodo"/>
<!--父亲给儿子传数据 父亲通过数据绑定传数据 儿子通过 props:['todos'],//声明接收todo 对象 -->
<MyList :todos="todos" :checkTodo="checkTodo" :deleteTodo="deleteTodo"/>
<MyFooter :todos="todos" :checkAllTodo="checkAllTodo" :clearAllTodo="clearAllTodo"/>
</div>
</div>
</div>
</template>
<script>
//样式的引入和这里有关系
import MyHeader from './components/MyHeader.vue';
import MyList from './components/MyList.vue';
import MyFooter from './components/MyFooter.vue';
export default {
name: 'App',
components: {
MyHeader,
MyList,
MyFooter
},
data(){
return {
todos:JSON.parse(localStorage.getItem("todos"))||[]
}
},
methods:{
// 添加一个todo
addTodo(todoObj){
// console.log('我是app组件,我收到了数据x==',todoObj);
this.todos.unshift(todoObj)
},
//勾选or 取消勾选 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)=>{
return todo.id!==id;
})
},
//全选or全不选
checkAllTodo(done){
this.todos.forEach((todo)=>{
todo.done=done
})
},
clearAllTodo(){
this.todos=this.todos.filter((todo)=>{
return !todo.done
})
}
},
watch:{
// todos(value){
// localStorage.setItem("todos", JSON.stringify(value));
// }
todos:{
deep:true,
handler(value){
localStorage.setItem("todos", JSON.stringify(value));
}
}
}
}
</script>
<style>
/* 整体样式 */
body {
background: rgba(230, 241, 245, 0.816);
}
.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>