Creating Universal Windows Apps With React Native

Installing React Native For Windows

Installing the React Native Universal Windows platform extension is easy, whether you want to add the Windows platform to your existing app, or you want to start from scratch building an app just for Windows.

Adding React Native for Windows to Existing Projects

React Native developers may be familiar with RNPM, a tool initially built to simplify the process of adding native dependencies to React Native projects. RNPM has a great plugin architecture upon which the React Native for Windows command line tools were built.

To start, make sure you have RNPM installed globally.

npm install -g rnpm

Once RNPM is installed, install the Windows plugin for RNPM and initialize your project.

npm install --save-dev rnpm-plugin-windows
rnpm windows

The windows command will do the following:

• Install react-native-windows from NPM,
• Read the name of your project from package.json,
• Use Yeoman to generate the Windows project files.

The RNPM plugin architecture searches your local package.json dependencies and devDependencies for modules that match rnpm-plugin-*, hence the –save-dev above.

Head to GitHub for more information on rnpm-plugin-windows.

Creating a React Native for Windows Project from Scratch

You have a few different options to create a React Native Universal Windows project from scratch. If your eventual intent is to also build apps for iOS and Android in the same code base, then the recommendation is to first use the existing tutorial to set up your React Native project, and then follow the steps above. E.g.,

<code=“language-bash”>npm install -g react-native-cli
react-native init myapp

Note: the react-native-windows NPM package is only compatible with the latest versions of react-native, from version 0.27 onwards.

Otherwise, you can easily set yourself up with npm init.

mkdir myapp
cd myapp
npm init
npm install --save-dev rnpm-plugin-windows
rnpm windows

Note: the default behavior for choosing the version of react-native-windows is to install the latest version if the package.json does not yet have a react-native dependency. Otherwise, if a react-native dependency already exists, the plugin will attempt to install a version of react-native-windows that matches the major and minor version of react-native.

The Windows plugin for RNPM will automatically install the react-native and react peer dependencies for react-native-windows if they have not yet been installed.

React Native For Windows Project Structure

There are a few boilerplate files that get generated for the Universal Windows App. The important ones include:

• index.windows.js — This is the entry point to your React application.
• windows/myapp.sln — This is where you should start to launch your app and debug native code.
• windows/myapp/MainPage.cs — This is where you can tweak the native bridge settings, like available modules and components.

Here’s the full output:

<code=“language-bash”>├── index.windows.js
├── windows
    ├── myapp.sln
    ├── myapp
        ├── Properties
            ├── AssemblyInfo.cs
            ├── Default.rd.xml
        ├── Assets
            ├── …
        ├── App.xaml
        ├── App.xaml.cs
        ├── MainPage.cs
        ├── project.json
        ├── Package.appxmanifest
        ├── myapp_TemporaryKey.pfx

We ship the core C# library for React Native as source on NPM. Having direct access to the source will help with debugging and making small tweaks where necessary. As long as the core ships as source, third party modules will also need to follow suit (although their dependencies may be binary). We’ll be working with the React Native community on react-native link support to make dependency management as simple as possible. Instructions for how to link dependencies are available on GitHub.

Building And Extending Apps For The Windows Platform

The core components and modules for React Native are imported as follows:

import {
  View,
  Text,
  Image
} from ‘react-native’;

import {
  TabBarIOS,
  DrawerLayoutAndroid
} from ‘react-native’;

import {
  FlipViewWindows,
  SplitViewWindows
} from ‘react-native-windows’;

import React, { Component } from ‘react’;
import {
  AppRegistry,
  StyleSheet,
  Text,
  View
} from ‘react-native’;
import {
  SplitViewWindows
} from ‘react-native-windows’;

import React, {Component} from ‘react’;
import {
  Platform,
  Text,
  View
} from ‘react-native’;


class HelloComponent extends Component {
  render() {
    var text = “Hello world!”;
    if (Platform.OS === ‘android’) {
      text = “Hello Android!”;
    } else if (Platform.OS === ‘windows’) {
      text = “Hello Windows!”;
    }

<span class="k">return</span> <span class="p">(</span>
  <span class="o">&lt;</span><span class="nx">View</span><span class="o">&gt;</span>
    <span class="o">&lt;</span><span class="nx">Text</span><span class="o">&gt;</span><span class="p">{</span><span class="nx">text</span><span class="p">}</span><span class="o">&lt;</span><span class="sr">/text</span><span class="err">&gt;


      </View>
    );
  }
}