初始化一个RN项目以后，接下来想要让Android与React Native通信

写一个继承自ReactContextBaseJavaModule类的子类，重写getName方法

package com.awesomeprojectimport android.util.Log
import android.widget.Toast
import com.facebook.react.bridge.Arguments
import com.facebook.react.bridge.ReactApplicationContext
import com.facebook.react.bridge.ReactContextBaseJavaModule
import com.facebook.react.bridge.ReactMethod
import com.facebook.react.modules.core.DeviceEventManagerModuleclass CustomModule(reactContext: ReactApplicationContext?) :ReactContextBaseJavaModule(reactContext) {companion object {const val TAG = "CustomModule"}/*** 返回注册module的名字*/override fun getName(): String {return "CustomModule"}@ReactMethodfun sendEvent(name: String?, msg: String?) {if (name != null && msg != null) {Toast.makeText(reactApplicationContext,"the name is $name: the msg is $msg",Toast.LENGTH_SHORT).show()}}@ReactMethodfun sendMessageToReactNative(msg: String?) {val params = Arguments.createMap()Log.i(TAG, "msg is $msg")params.putString("name", msg)// 传递给js端参数reactApplicationContext.getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter::class.java).emit("customEventName", params)}
}

重写一个继承自ReactPackage类的子类，重写createNativeModules和createViewManagers方法

package com.awesomeprojectimport android.view.View
import com.facebook.react.ReactPackage
import com.facebook.react.bridge.NativeModule
import com.facebook.react.bridge.ReactApplicationContext
import com.facebook.react.uimanager.ReactShadowNode
import com.facebook.react.uimanager.ViewManagerclass CustomPackage : ReactPackage {/*** 返回nativeModule的集合*/override fun createNativeModules(reactContext: ReactApplicationContext): MutableList<NativeModule> = listOf(CustomModule(reactContext)).toMutableList()override fun createViewManagers(context: ReactApplicationContext):MutableList<ViewManager<View, ReactShadowNode<*>>> = mutableListOf()}

然后在MainApplication里写一个reactNativeHost实例化对象，其中在getPackages方法里注册自己刚才写的CustomPackage。

class MainApplication : Application(), ReactApplication {override val reactNativeHost: ReactNativeHost =object : DefaultReactNativeHost(this) {override fun getPackages(): List<ReactPackage> = PackageList(this).packages.apply {add(CustomPackage())}override fun getJSMainModuleName(): String = "index"override fun getUseDeveloperSupport(): Boolean = BuildConfig.DEBUGoverride val isNewArchEnabled: Boolean = BuildConfig.IS_NEW_ARCHITECTURE_ENABLEDoverride val isHermesEnabled: Boolean = BuildConfig.IS_HERMES_ENABLED}override val reactHost: ReactHostget() = getDefaultReactHost(this.applicationContext, reactNativeHost)override fun onCreate() {super.onCreate()SoLoader.init(this, false)if (BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {// If you opted-in for the New Architecture, we load the native entry point for this app.load()}ReactNativeFlipper.initializeFlipper(this, reactNativeHost.reactInstanceManager)}
}

然后在RN工程目录下新建一个

import React, {useEffect} from 'react';
import {Alert, Button, NativeEventEmitter, NativeModules} from 'react-native';
const {CustomModule} = NativeModules;const AndroidButtonComponent = () => {useEffect(() => {const nativeModuleEmitter = new NativeEventEmitter(CustomModule);// 监听Android端传递过来的数据nativeModuleEmitter.addListener('customEventName', data => {// 打印从Android端传递来的参数的key-valuefor (const key in data) {console.log('key is ' + key + ' value is ' + data[key]);}// 这里为了更明显的看到Android端传递过来的参数，将其取出来通过弹窗的形式打印Alert.alert('提示',data.name,[{text: '取消', onPress: () => console.log('取消按钮被点击')},{text: '确定', onPress: () => console.log('确定按钮被点击')},],{cancelable: false},);});return () => {nativeModuleEmitter.removeAllListeners('customEventName');};}, []);// 写button按压下去的一个函数const onPress = () => {// CustomModule.sendEvent('Tom', 'How are you?');// 调用Android端的函数CustomModule.sendMessageToReactNative('Android-Message');};return <Button title={'Say Hello'} color={'#841584'} onPress={onPress} />;
};export default AndroidButtonComponent;

最后在App.jsx文件当中，将这个组件导出。

可以通过这行命令来启动debug模式

npx react-native start --experimental-debugger

然后输入J可以进入debug的控制台

在这里可以看到打印的日志

最后效果如图所示：

点击这个say hello的button之后，会弹窗提示

file_v3_00bt_1cf1a7b1-90d3-439d-a8ce-08ab5aa5d8ag.MP4

参考：

• 【笔记】React-Native跟Android交互--简单示例_react-native如何调用安卓-CSDN博客
• Android与RN的交互与通信_rn android event-CSDN博客