Understanding React Native’s Bridge for Android

Written by: Mebratu

1 min read

React Native is a popular cross-platform development framework that allows developers to write native apps for both iOS and Android using the same code-base. At the heart of React Native lies
the concept of a bridge, which enables bidirectional and asynchronous communication between JavaScript and native code. This blog post will focus specifically on the bridge for Android.
So, What is React Native Bridging?React Native bridging is a mechanism developed by the React team that allows developers to build their own custom modules, if the default components provided by React do not meet the requirements. It enables developers to write native code (both Android and iOS) and communicate between native code and React Native JavaScript code to achieve custom functionality. Creating A Custom Native Module in Android1. Create a Java class file that will contain all the native logic you want to execute and variables and callbacks you want to export to JavaScript.

Here is a simple example of a native module named CalendarModule:
package com.name-of-package-name;

import com.facebook.react.bridge.NativeModule;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;
class CalendarModule(reactContext: ReactApplicationContext) :
ReactContextBaseJavaModule(reactContext) {...}

2. Create a Java package for the Java class you just created and register the module in this package.
The package should implement the ReactPackage interface and override the createNativeModules method to return a list containing instances of your native module classes.

3.Make the package available in the JavaScript code by adding your package in the return array of getPackages() method in the MainApplication.java file.

4. Access the native module in your JavaScript code. You can do this by importing NativeModules from react-native and then destructuring the specific module you want to use:

import { NativeModules } from 'react-native';
const { CalendarModule } = NativeModules;

ConclusionReact Native bridging is a powerful feature that allows developers to leverage native capabilities that are not available in the React Native environment. By understanding how to create and use
native modules, developers can extend the functionality of their apps beyond what is possible with React Native alone.