Vue2.0学习—Todolist案例（五十九）

Posted 2022-11-23 王同学要努力

【Vue2.0学习】—Todolist案例（五十九）

组件化编码流程

1、实现静态组件：抽取组件，使用组件实现静态效果

2、展示动态数据：

• 数据的类型、名称是什么
• 数据保存在哪个组件

3、交互—从绑定事件监听开始

废话不多说，直接上代码

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" 
                 :clearAllTodo="clearAllTodo" />
            </div>
        </div>
    </div>


</template>

<script>
    import MyHeader from './components/MyHeader.vue'
    import List from './components/List.vue'
    import MyFooter from './components/MyFooter.vue'




    export default 
        name: 'App',
        components: 
            MyHeader,
            List,
            MyFooter
        ,
        data() 
            return 
                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 todo
            addtodo(todoObj) 
                this.todos.unshift(todoObj)

            ,
            //勾选or取消勾选
            checkTodo(id) 
                this.todos.forEach((todo) => 
                    //函数体
                    if (todo.id === id) 
                        todo.done = !todo.done;
                    
                )
            ,
            //删除
            deleteTodo(id) 
                this.todos = this.todos.filter(todo => todo.id !== id)

            ,
            //全选全不选
            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>

<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>

Item组件

<template>
    <li>
        <label>
            <input type="checkbox" 
            :checked="todo.done"
             @change="handleCheck(todo.id)" />
            <!-- <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to对象
        props: ['todo','checkTodo','deleteTodo'],
        methods: 
            //勾选
            handleCheck(id) 
                //通知APP组件将对应的组件
               this.checkTodo(id)
            ,
            //删除
            handleDelete(id) 
                if (confirm('确定删除吗？')) 
               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>

List组件

<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 './Item.vue'
    export default 
        name: 'List',
        props: ['todos', 'checkTodo', 'deleteTodo'],
        components: 
            Item
        ,
    
</script>

<style scoped>
    /*main*/
    .todo-main 
        margin-left: 0px;
        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>

MyFooter组件

<template>
    <div class="todo-footer" v-show="total">
        <label>
            <input type="checkbox" :checked="isAll" @change="checkAll">
        </label>
        <span>
            <span>doneTotal</span> / 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', 'checkAllTodo','clearAllTodo'],
        computed: 
            total() 
                return this.todos.length
            ,
            isAll() 
                return this.doneTotal === this.total && this.total > 0

            ,
            doneTotal() 
                let i = 0
                this.todos.forEach((todo) => 
                    if (todo.done) i++
                )
                return i
                //    const x= this.todos.reduce(()=>
                //     console('@',pre,current)
                //     return pre+(current.done ? 1:0)
                //     ,0)

                //  return this.todos.reduce((pre,todo)=>pre+(todo.done?1:0),0)
            
        ,
        methods: 
            checkAll(e) 
                this.checkAllTodo(e.target.checked)

            ,
            clearAll()
                this.clearAllTodo()

            
        
    
</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>

MyHeader组件

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


<script>
import nanoid from 'nanoid'
    export default 
        name: 'MyHeader',
        props:['addtodo'],
        data()
            return
                title:''
            
        ,
        methods: 
            add() 
                //将用户的输入包装成一个对象
                //校验数据
                if(!this.title.trim()) return alert('输入不能为空')
            //将用户包装成一个对象
                const todoObj=id:nanoid(),title:this.title,done:false                                  
                     //通知APP组件去添加一个对象
                this.addtodo(todoObj);
                // 清空todo
                 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>

Todolist案例总结

1️⃣组件化编码流程：

• 拆分静态组件：组件要按照功能点拆分，命名不要与html冲突
• 实现动态组件：考虑好组件的存放位置，数据是一个组件在用，还是一些组件在用
• 一个组件在用：放在组件自身即可
• 一些组件在用：放在他们共同的父组件上（状态提升）
• 实现交互：从绑定事件开始

2️⃣props适用于

• 父组件=>子组件通信
• 子组件=>父组件通信（要求先给子一个函数）

3️⃣使用v-model时要切记：

• v-model绑定的值不能是props传过来的值，因为props是不可以修改的
• props传过来的值若是对象类型的值，修改对象中的属性时Vue不会报错，但是不推荐这样做