React Native Integrating with an existing native app (Android)

In this article we will learn about how to integrate React-Native to an existing android app. This tutorial is made under the following environment

react-native-cli: 2.0.1
react-native: 0.50.3

As changing of version in react-native there me be some breaking changes but still flow of integration will be same.

Lets create a new react native project using react-native-cli,

react-native init myReactApp

then go to root project of your android app and create a folder named reactNativeSrc, (This is not monetary but it keep react native code isolated from native code)

Now add a package.json file into root of the native android project then add following lines

“name”: “myApp”,
“version”: “0.0.1”,
“private”: true,
“scripts”: {
“start”: “node node_modules/react-native/local-cli/cli.js start”
“dependencies”: {
“react”: “16.0.0”,
“react-native”: “0.50.4”

Then copy all of your react native project except ios , android and node_modules in to the reactNativeSrc directory.

Android File Structure

Note : android minimum sdk version ≥16

Now follow this steps :

Now open which is located at project root directory myProj/build.gradle and in then all project block add following line.

allprojects {
repositories {

maven {
// All of React Native (JS, Android binaries) is installed from npm
url “$rootDir/node_modules/react-native/android”


Now open which is located at project directory myProj/app/build.gradle and in then all project block add following line.

compile ‘’
compile “com.facebook.react:react-native:+”

Now run gradle sync it should be run without any error now.

Now add a index.js file on to the root of the project directory then put the following code.

import React from 'react';
import {
} from 'react-native';
class HelloUser extends React.Component {
render() {
return (
<View style={styles.container}>
<Text style={styles.hello}>Hey! How are you?</Text>
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
hello: {
fontSize: 20,
textAlign: 'center',
margin: 10,
AppRegistry.registerComponent('myApp', () => HelloUser);

Let’s do some native codding

Now create a activity select myapp.pacakeg→ file→ new→ javaclass
Name it MyReactActivityand add the following code.

package com.ranvir.applicationint;
import android.os.Bundle;
import android.view.KeyEvent;
import com.facebook.react.ReactInstanceManager;
import com.facebook.react.ReactRootView;
import com.facebook.react.common.LifecycleState;
import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;

public class MyReactActivity extends Activity implements DefaultHardwareBackBtnHandler {
private ReactRootView mReactRootView;
private ReactInstanceManager mReactInstanceManager;
protected void onCreate(Bundle savedInstanceState) {
 mReactRootView = new ReactRootView(this);
mReactInstanceManager = ReactInstanceManager.builder()
.addPackage(new MainReactPackage())
mReactRootView.startReactApplication(mReactInstanceManager, "myApp", null);
public void invokeDefaultOnBackPressed() {
protected void onPause() {
 if (mReactInstanceManager != null) {
protected void onResume() {
 if (mReactInstanceManager != null) {
protected void onDestroy() {
 if (mReactInstanceManager != null) {
public void onBackPressed() {
if (mReactInstanceManager != null) {
} else {
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_MENU && mReactInstanceManager != null) {
return true;
return super.onKeyUp(keyCode, event);

Now add to Manifest.xml


Now add overlay permission check to the react native app add following code to, It is necessary for development only.

package com.ranvir.applicationint;import;import android.content.Intent;import;import android.os.Build;import android.provider.Settings;import;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import com.facebook.react.*;import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;import;public class MainActivity extends AppCompatActivity implements View.OnClickListener {
 Button myButton; public static int OVERLAY_PERMISSION_REQ_CODE = 2; @Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); myButton = (Button) findViewById(; myButton.setOnClickListener(this); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (!Settings.canDrawOverlays(this)) {
Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION, Uri.parse("package:" + getPackageName())); startActivityForResult(intent, OVERLAY_PERMISSION_REQ_CODE); }
 @Override public void onClick(View view) {
//Log.i("Test","Hello World"); Intent intent = new Intent(this, MyReactActivity.class); startActivity(intent); }
 @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (!Settings.canDrawOverlays(this)) {
// SYSTEM_ALERT_WINDOW permission not granted... }
Final output will look like this.

Some extra, you need to add a button to invoke react-native module onClick, after this when you click on this button it will open a new intent in native app.

Originally published at on January 1, 2018.

One clap, two clap, three clap, forty?

By clapping more or less, you can signal to us which stories really stand out.