<template>
 <div>
 {{fatherText}}
 <Child v-model="fatherText"></Child>//调用子组件，并将 fatherText传递给子组件
 <button @click="changeChild">changeChildButton</button>
 </div>
</template>

<script>
import Child from "./Child.vue";
export default {
 name: "father",
 data() {
 return {
 fatherText: "i'm fathertext"
 };
 },
 components: {
 Child
 },
 methods: {
 changeChild() {
 this.fatherText = "father change the text";
 }
 }
};
</script>

<template>
 <div>
 <p class="child" @click="change">{{fatherText}}</p>//正常使用fatherText的值，并添加一个修改值 的方法
 </div>
</template>
<script>
export default {
 name: "child",
 model: {//添加了model方法，用于接收v-model传递的参数
 prop: "fatherText", //父组件中变量的传递
 event: "changeChild" //事件传递
 },
 props: {
 fatherText: {//正常使用props接收fatherText的值
 type: String
 }
 },
 data() {
 return {
 
 };
 },
 methods: {
 change(){
  this.fatherText = 'son change the text'
 }
 }
};
</script>

<template>
 <div>
 <p class="child" @click="change">{{childText}}</p>
 </div>
</template>
<script>
export default {
 name: "child",
 model: {
 prop: "fatherText", //父组件中变量的传递
 event: "changeChild" //事件传递
 },
 props: {
 fatherText: {
 type: String
 }
 },
 data() {
 return {
 childText: this.fatherText //定义自己的变量childText
 };
 },
 methods: {
 change() {
 this.childText = "son change the test";//修改自己的变量
 }
 }
};

<template>
 <div>
 <p class="child" @click="changeChild">{{childText}}</p>
 </div>
</template>
<script>
export default {
 name: "child",
 model: {
 prop: "fatherText", //父组件中变量的传递
 event: "changeChild" //事件传递
 },
 props: {
 fatherText: {
 type: String
 }
 },
 data() {
 return {
 childText: this.fatherText
 };
 },
 methods: {
 changeChild() {
 this.childText = "son change the test";
 }
 },
 watch: {
 fatherText(newtext) {//使用父组件中变量名为函数名，监听fatherText的变化，如果变化，则改变子组件中的值
 this.childText = newtext;
 },
 childText(newtext) {//监听子组件中childText变化，如果变化，则通知父组件，进行更新
 this.$emit("changeChild", newtext);
 }
 }
};