React 实现爷孙组件间相互通信

//跨组件通信
import React, { Component } from 'react'
//创建context 给初始值
const UserMessage = React.createContext({
    nickName: 'yyy',
    level: 1
})

export default class TextSingal extends Component {
    constructor(props) {
        super(props)
        this.state = {
            nickName: 'kkk',
            level: 99,
            name: 'ppp',
            age: 9999
        }
    }
    render() {
        const { name, age } = this.state
        return (
            <div>
                <h2>爷爷组件</h2>
                <h3>name:{name}</h3>
                <h3>age:{age}</h3>
                {/* 改变数据孙组件也更新 */}
                <button onClick={() => this.handelClick()}>updated</button>
                {/* 传入state对象和foo回调函数 */}
                {/* foo函数用于孙组件和爷组件通信 */}
                <UserMessage.Provider value={{ ...this.state, foo: (name, age) => this.updateDatas(name, age) }}>
                    <Father />
                </UserMessage.Provider>

            </div>
        )
    }
    handelClick() {
        this.setState({
            nickName: '虎威神',
            level: 9999
        })
    }
    updateDatas(name, age) {
        this.setState({
            name,
            age
        })
    }
}

class Father extends Component {
    render() {
        return (
            <div>
                <h2>爸爸组件</h2>
                <Son />
            </div>
        )
    }
}
class Son extends Component {
    render() {
        // 解构
        const { nickName, level, foo } = this.context
        return (
            <div>
                <h2>儿子组件</h2>
                <h3>nickname:{nickName}</h3>
                <h3>level:{level}</h3>
                {/* 下面两种调用方式都可以 */}
                {/* 改变爷组件的数据 */}
                <button onClick={() => this.handelClick()}>updated</button>
                <button onClick={() => foo('牛霸天', 18)}>updated</button>
            </div>
        )
    }
    handelClick() {
        this.context.foo('牛霸天', 18)
    }
}
// 接受爷组件传递的值
Son.contextType = UserMessage