Todo-List案例版本四-Toy模板网

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Todo-List案例版本四,vue,vue.js,前端,javascript

全局事件总线

Todo-List案例版本四,vue,vue.js,前端,javascript

使用步骤

1.定义全局事件总线

new Vue({
    ...
    beforeCreated(){
        Vue.prototype.$bus=this    //安装全局事件总线，$bus就是当前应用的vm
    }
    ...
})

2.使用事件总线

a.接收数据：A组件想接收数据，则在A组件中给$bus绑定自定义事件，事件的回调留在A组件自身

export default{
    methods(){
        demo(data){...}
    }
    ...
    mounted(){
        this.$bus.$on('xxx',this.demo)
    }
}

b.提供数据：this.$bus.$emit('xxx',data)

3.最好在beforeDestroy钩子中，用$off()去解绑当前组件所用到的事件

实例

src/main.js

import Vue from 'vue'
import App from './App.vue'

Vue.config.productionTip = false

Vue.prototype.x={a:1,b:2}

//创建vm
new Vue({
    el: '#app',
    render: h => h(App),
    beforeCreate(){
        Vue.prototype.$bus=this
    }
})

src/App.vue

<template>
    <div class="app">
        <h1>{{ msg }}</h1>
        <School/>
        <Student/>
    </div>
</template>

<script>
import Student from './components/Student'
import School from './components/School'

export default {
    name: 'App',
    data() {
        return {
            msg: '你好啊！'
        }
    },
    components: { Student, School }
}
</script>

<style scoped>
.app {
    background-color: gray;
    padding: 5px;
}
</style>

src/components/Student.vue

<template>
    <div class="student">
        <h2>学生姓名：{{ name }}</h2>
        <h2>学生性别：{{ sex }}</h2>
        <button @click="sendStudentName">发送学生名字到学校</button>
    </div>
</template>

<script>
export default {
    name: 'Student',
    data() {
        return {
            name:'张三',
            sex:'男'
        }
    },
    methods:{
        sendStudentName(){
            this.$bus.$emit('hello',this.name)
        }
    }
}
</script>

<style lang="less">
    .student{
        background-color: pink;
        padding: 5px;
        margin-top: 30px;
    }
</style>

src/components/School.vue

<template>
    <div class="school">
        <h2>学校名称：{{ name}}</h2>
        <h2>学校地址：{{ address }}</h2>
    </div>
</template>

<script>
export default {
    name: 'School',
    data() {
        return {
            name:'黑马',
            address:'广州'
        }
    },
    mounted(){
        this.$bus.$on('hello',(data)=>{
            console.log('我是School组件，收到了数据',data);
        })
    },
    beforeDestroy(){
        this.$bus.$off('hello')
    }
}
</script>

<style scoped>
    .school{
        background-color: skyblue;
        padding: 5px;
    }
</style>

Todo-List案例版本四,vue,vue.js,前端,javascript

以上是对全局事件总线的运用，接下来是案例使用

(161条消息) Todo-List案例版本三_bubbleJessica的博客-CSDN博客

使用全局事件总线完善

src/main.js

import Vue from 'vue'
import App from './App.vue'

Vue.config.productionTip = false

//创建vm
new Vue({
    el: '#app',
    render: h => h(App),
    beforeCreate(){
        Vue.prototype.$bus=this //安装全局事件总线
    }
})

src/App.vue

<template>
    <div id="root">
        <div class="todo-container">
            <div class="todo-wrap">
                <MyHeader @addToDo="addToDo" />
                <MyList :todos="todos" />
                <MyFooter :todos="todos" @checkAllTodo="checkAllTodo" @clearAllTodo="clearAllTodo" />
            </div>
        </div>
    </div>
</template>

<script>
import MyHeader from './components/MyHeader'
import MyList from './components/MyList'
import MyFooter from './components/MyFooter'

export default {
    name: 'App',
    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: JSON.parse(localStorage.getItem('todos')) || []
        }
    },
    components: { MyHeader, MyList, MyFooter },
    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) {
            // 注意:filter不改变原数组，只是新建一个数组
            this.todos = this.todos.filter((todo) => {
                return todo.id !== id
            })
        },
        // 全选or取消全选
        checkAllTodo(done) {
            this.todos.forEach((todo) => {
                todo.done = done
            })
        },
        // 清除所有已完成的todo
        clearAllTodo() {
            this.todos = this.todos.filter((todo) => {
                return !todo.done
            })
        }
    },
    watch: {
        // todos简写不包含深度监视
        // todos(value) {
        //     localStorage.setItem('todos', JSON.stringify(value))
        // }

        // todos完整版深度监视
        todos:{
            deep:true,
            handler(value){
                localStorage.setItem('todos', JSON.stringify(value))
            }
        }
    },
    mounted(){
        this.$bus.$on('checkTodo',this.checkTodo)
        this.$bus.$on('deleteTodo',this.deleteTodo)
    },
    beforeDestroy() {
        this.$bus.$off('checkTodo')
        this.$bus.$off('deleteTodo')
    },
}
</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>

src/components/MyList.vue

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

<script>
import MyItem from './MyItem.vue'

export default {
    name: 'MyList',
    props:['todos'],
    components: { MyItem }
}
</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>

src/components/MyItem.vue

<template>
    <li>
        <label>
            <input type="checkbox" :checked="todo.done" @change="handleCheck(todo.id)" />
            <!-- 以下代码也能实现功能，但是不太推荐，因为有点违反规则，因为修改了props，只不过vue没有监测到（vue监测到的情况是对象全部被变化 -->
            <!-- <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: 'MyItem',
    //声明接收todo对象
    props: ['todo'],
    methods: {
        handleCheck(id) {
            // 通知App组件将对应的todo对象的done值取反
            // console.log(id);
            // this.checkTodo(id)
            this.$bus.$emit('checkTodo',id)
        },
        handleDelete(id){
            if(confirm('确定删除吗？')){
                // this.deleteTodo(id)
                this.$bus.$emit('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>

Todo-List案例版本四,vue,vue.js,前端,javascript 文章来源地址https://www.toymoban.com/news/detail-546622.html