vue 组件 子向父亲通信用自定义方法用事件监听

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Title of page</title>
</head>
<body>

<div id="example">
<input v-model="parentsg">
<br>
<child v-bind:parentsg="parentsg"></child>
<!-- 直接绑定根数据text ，但是必须指明根数据的路径shou.text-->
<todo-item v-bind:todo="todo"></todo-item>
</div>
<div id="counter-event-example">
<p>{{childtofather}}</p>
<p>{{ total }}</p>
<button-counter v-on:increment="incrementTotal"></button-counter>
<button-counter v-on:increment="incrementTotal"></button-counter>
</div>

</body>
<script src="https://cdn.jsdelivr.net/npm/vue@2.5.13/dist/vue.js"></script>
<script >
// 注册
Vue.component('child', {
props: ['parentsg'],
template: '<span>{{ parentsg}}</span>'
})
Vue.component('todo-item', {
props: ['todo'],
template: '<p>{{todo.isComplete}}</p>'
})

// 创建根实例
new Vue({
el: '#example',
data:{

parentsg:'',
todo: {
text: 'Learn Vue',
isComplete: false
},
shou: {
text: 'shi wo ma',
isComplete: false
}

}

})

Vue.component('button-counter', {
template: '<button v-on:click="incrementCounter">{{ counter }}</button>',
data: function () {
return {
counter: 0
}
},

// 绑定了事件click————>increment

// 然后 this.counter += 1; this.$emit('increment1',this.counter);

// 这边就是触发事件 increment1，参考文献里面有点乱，这边是不是清晰多了

// 然后 <button-counter v-on:increment1="incrementTotal"></button-counter>

// v-on相当于监听吧，就触发 incrementTotal

// 传给父组件的参数 输出// this.counter

// 有没有很清晰，若有理解不对的地方，请指正
methods: {
incrementCounter: function () {
this.counter += 1
this.$emit('increment',this.counter)
}
},
})

new Vue({
el: '#counter-event-example',
data: {
total: 0,
childtofather:''
},
methods: {
incrementTotal: function (e) {

this.total += 1;
//输出 this.counter
console.log(e)
//
this.childtofather=e +"子传父传来的数据"
}
}
})
</script>
</html>