react-native/docs/EmbededApp.md

---
id: embeded-app
title: Use React Native in Existing iOS App
layout: docs
category: Guides
permalink: docs/embeded-app.html
next: activityindicatorios
---

## Install React Native Using Cocoapods

[Cocoapods](http://cocoapods.org/) is a package management tool for iOS/Mac development. We need to use it to download React Native. If you haven't install Cocoapods yet, checkout [this tutorial](http://guides.cocoapods.org/using/getting-started.html).

When you are ready to work with Cocoapods, add the following line to `Podfile`. If you don't have one, then create it under the root directory of your project.

	pod 'React'
	pod 'React/RCTText'  
	# Add any subspecs you want to use in your project

Remember to install all subspecs you need. The `<Text>` element cannot be used without `pod 'React/RCTText'`.
	
Then install pods via shell

	$ pod install --verbose
	
The installation process also requires [Node.js](http://nodejs.org).

## Create Your React Native App

First, enter React Native's pod root directory and create **index.ios.js** inside a directory `ReactComponent`.

	$ cd Pods/React
	$ mkdir ReactComponent
	$ touch index.ios.js
	
Copy & paste following starter code for **index.ios.js**.

	var React = require('react-native');

	var {
	  Text
	} = React;
	
	class SimpleApp extends React.Component {
	  render() {
	    return <Text>This is a simple application.</Text>
	  }
	}
	
	AppRegistry.registerComponent('SimpleApp', () => SimpleApp);
	
`SimpleApp` will be your **module name**, which will be used later on.

## Add Container View To Your App

You should now add container view for React Native component. It can be any **UIView** in your app.

![Container view example](http://7qn8cx.com1.z0.glb.clouddn.com/c37deb761ce048225989ece06cf3d185061c511d-74d3e6b285e1b5cd93153c39fca63c63838b8dbf.png?imageView2/2/h/400/w/400/q/85)

However, let's subclass **UIView** for the sake of clean code. Let's name it **ReactView**. Open up **Yourproject.xcworkspace** and create a new class **ReactView** (You can name it whatever you like :)).  

	// ReactView.h
	
	#import <UIKit/UIKit.h>
	@interface ReactView : UIView
	@end


Don't forget to add an outlet for it.
	
	// ViewController.m

	@interface ViewController ()
	@property (weak, nonatomic) IBOutlet ReactView *reactView;
	@end
	
Here I disabled **AutoLayout** for simplicity. In real production world, you should turn on AutoLayout and setup constraints by yourself.

## Add RCTRootView To Container View

Ready for the most interesting part? Now we shall create the **RCTRootView**, where your React Native app lives in. 

In **ReactView.m**, we need to first initiate **RCTRootView** with the URI of your **index.ios.bundle**. **index.ios.bundle** will be created by packager and served by React Native server, which will be discussed later on.

    NSString *urlString = @"http://localhost:8081/index.ios.bundle";
    NSURL *jsCodeLocation = [NSURL URLWithString:urlString];
    RCTRootView *rootView = [[RCTRootView alloc] initWithBundleURL:jsCodeLocation
                                                        moduleName: @"SimpleApp"
                                                     launchOptions:nil];
Then add it as a subview of the **ReactView**.

    [self addSubview:rootView];
    rootView.frame = self.bounds;
    
## Start Development Server

In root directory, we need to start React Native development server. 

	$ ./Pods/React/packager/packager.sh --root ./ReactComponents
	
`--root` indicates the root of your React Native apps. Here we just have one **index.ios.js**. React Native development server will use packager to create a **index.ios.bundle**. Which can be access via `http://localhost:8081/index.ios.bundle`.

## Compile And Run

Now compile and run your app. You shall now see your React Native app running inside of the **ReactView**.

![Example](http://7qn8cx.com1.z0.glb.clouddn.com/0c4e7b977f1db688b60f1579a581f30dd1abc85f-86bebe4092e82c395e322fefcc8f7727b0820ac7.png?imageView2/2/h/400/w/400/q/85)

## Conclusion

So under the hood, when **RCTRootView** is initialized, it will try to download, parse and run the bundle file from React Native development server. All you need to do is to implement your own container view, add **RCTRootView** as its subclass. And then serve the bundle using React Native development server. Then, bravo!

You can checkout full source code of sample application [here](https://github.com/tjwudi/EmbededReactNativeExample).