React Native的WebView与html双向通信

安卓、ios原生与html双向通信相对简单且成熟，但是React Native与html的双向通信存在那么一丢丢的坑

一、参数配置

导包

import { WebView } from 'react-native-webview'

使用

<WebView
    ref={ref => this.webViewRef = ref}
    source={{ uri: url }}
    // source={{ html }}
    javaScriptEnabled
    useWebKit
    allowFileAccess
    startInLoadingState
    onLoadStart={this.onLoadStart}
    onError={this.onError}
    onLoad={this.onLoad}
    onLoadEnd={this.onLoadEnd}
    renderLoading={this.renderLoading}
    renderError={this.renderError}
    javaScriptCanOpenWindowsAutomatically
    onMessage={this.handleMessage}
    injectedJavaScript={`(function() {window.postMessage = function(data) {window.ReactNativeWebView.postMessage(data)}})();`}

相关回调函数

onLoadStart = ({ nativeEvent }) => {
    console.log('onLoadStart', nativeEvent)
}
onError = ({ nativeEvent }) => {
    console.log('onError', nativeEvent)
}
onLoad = ({ nativeEvent }) => {
    this.setState({ title: nativeEvent.title })
    console.log('onLoad', nativeEvent)
}
onLoadEnd = ({ nativeEvent }) => {
    console.log('onLoadEnd', nativeEvent)
}
renderLoading = () => {
    console.log('renderLoading')
}
renderError = ({ nativeEvent }) => {
    console.log('renderError', nativeEvent)
}
handleMessage = async ({ nativeEvent }) => {
    const { actionType, extra } = nativeEvent.data && JSON.parse(nativeEvent.data) || {}
}

二、坑点

2.1、react-native-webview使用postMessage后H5不能监听问题

注意：这里安卓用document，ios用window，否则会出现react-native-webview使用postMessage后H5不能监听问题

/* 监听rn消息 */
const eventListener = nativeEvent => {
    //解析数据actionType、extra
    const {actionType, extra} = nativeEvent.data && JSON.parse(nativeEvent.data) || {}
}
//安卓用document，ios用window
window.addEventListener('message', eventListener);
document.addEventListener('message', eventListener);

2.2、RN的webview的onMessage监听不到的问题

injectedJavaScript={`(function() {window.postMessage = function(data) {window.ReactNativeWebView.postMessage(data)}})();`}

注意这里要加上injectedJavaScript，它重写window.postMessage方法解决了RN的webview的onMessage监听不到的问题

三、React Native与html双向通信

3.1、RN发数据到WebView

RN通过postMessage发送数据

const temp = {
    actionType: 'takePhoto',
    extra: {
        fileId: '1522501682737836034',
        fileUrl: 'https://gongbao-phoenix.oss-cn-hangzhou.aliyuncs.com/test/330100/1/2022/05/06/2efb943b439146ed86db0ad920c7edaf.jpg',
        originalFileName: 'E91FDC71-FD9C-49B9-B038-529C9CDC149B.jpg',
        tag: 'not_use',
        unionId: 'f143153ed07a428fa6308d6f73b1a2b9',
    },
}
this.webViewRef.postMessage(JSON.stringify(temp))

webView接受数据

/* 监听rn消息 */
const eventListener = nativeEvent => {
    const {actionType, extra} = nativeEvent.data && JSON.parse(nativeEvent.data) || {}
    
}
//安卓用document，ios用window 
window.addEventListener('message', eventListener);
document.addEventListener('message', eventListener);

3.2、WebView发数据到RN

WebView通过postMessage发送数据

const action = {
    actionType: 'viewPicture',
    extra: {
        pics: ['https://tva1.sinaimg.cn/large/e6c9d24ely1h0svk2jlcej20ps11ewld.jpg'],
        defaultIndex: 0,
    },
}
window.postMessage(JSON.stringify(action));

RN注册onMessage接收

onMessage={this.handleMessage}

handleMessage = async ({ nativeEvent }) => {
    const { actionType, extra } = nativeEvent.data && JSON.parse(nativeEvent.data) || {}
}

四、demo源码

import React, { Component } from 'react'
import {
    DeviceEventEmitter,
    StyleSheet, 
} from 'react-native'
import { WebView } from 'react-native-webview'
import NavigatorBar from '../../components/NavigatorBar'
import { SafeAreaView } from '../../components'

export default class WebViewPage extends Component {

    state = {
        title: '',
        showBackAction: false,
    }

    _autoCheckNavigationBar = nativeEvent => {
        const { canGoBack } = nativeEvent
        this.setState({ showBackAction: canGoBack })
        DeviceEventEmitter.emit('showTabBar', !canGoBack)
    }

    onLoadStart = ({ nativeEvent }) => {
        console.log('onLoadStart', nativeEvent)
    }

    onError = ({ nativeEvent }) => {
        console.log('onError', nativeEvent)
    }

    onLoad = ({ nativeEvent }) => {
        this.setState({ title: nativeEvent.title })
        console.log('onLoad', nativeEvent)
    }

    onLoadEnd = ({ nativeEvent }) => {
        console.log('onLoadEnd', nativeEvent)
        this._autoCheckNavigationBar(nativeEvent)
    }

    renderLoading = () => {
        console.log('renderLoading')
    }

    renderError = ({ nativeEvent }) => {
        console.log('renderError', nativeEvent)
    }

    handleMessage = async ({ nativeEvent }) => {
        const { actionType, extra } = nativeEvent.data && JSON.parse(nativeEvent.data) || {}
    }

    render() {
        const { showBackAction } = this.state
        const { url } = this.props || {}
        return (
            <SafeAreaView style={styles.container} hideBottomView={!showBackAction}>
                <NavigatorBar
                    backAction={showBackAction && this.webViewRef.goBack}
                    title={this.state.title}
                />
                <WebView
                    ref={ref => this.webViewRef = ref}
                    // source={{ uri: url }}
                    source={{ html }}
                    javaScriptEnabled
                    useWebKit
                    allowFileAccess
                    startInLoadingState
                    onLoadStart={this.onLoadStart}
                    onError={this.onError}
                    onLoad={this.onLoad}
                    onLoadEnd={this.onLoadEnd}
                    renderLoading={this.renderLoading}
                    renderError={this.renderError}
                    javaScriptCanOpenWindowsAutomatically
                    onMessage={this.handleMessage}
                    injectedJavaScript={`(function() {window.postMessage = function(data) {window.ReactNativeWebView.postMessage(data)}})();`}
                />
            </SafeAreaView>
        )
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        backgroundColor: '#F5FCFF',
    },
})

const html = `



    
    
    



    1,viewPicture
    
receive react native data: 




`