Building React Native from source #

You will need to build React Native from source if you want to work on a new feature/bug fix, try out the latest features which are not released yet, or maintain your own fork with patches that cannot be merged to the core.

Prerequisites #

Assuming you have the Android SDK installed, run android to open the Android SDK Manager.

Make sure you have the following installed:

1. Android SDK version 23 (compileSdkVersion in build.gradle)
2. SDK build tools version 23.0.1 (buildToolsVersion in build.gradle)
3. Android Support Repository >= 17 (for Android Support Library)
4. Android NDK (download links and installation instructions below)

Point Gradle to your Android SDK: #

Step 1: Set environment variables through your local shell.

Note: Files may vary based on shell flavor. See below for examples from common shells.

• bash: .bash_profile or .bashrc
• zsh: .zprofile or .zshrc
• ksh: .profile or $ENV

Example:

Step 2: Create a local.properties file in the android directory of your react-native app with the following contents:

Example:

Download links for Android NDK #

1. Mac OS (64-bit) - http://dl.google.com/android/repository/android-ndk-r10e-darwin-x86_64.zip
2. Linux (64-bit) - http://dl.google.com/android/repository/android-ndk-r10e-linux-x86_64.zip
3. Windows (64-bit) - http://dl.google.com/android/repository/android-ndk-r10e-windows-x86_64.zip
4. Windows (32-bit) - http://dl.google.com/android/repository/android-ndk-r10e-windows-x86.zip

You can find further instructions on the official page.

Building the source #

1. Installing the fork #

First, you need to install react-native from your fork. For example, to install the master branch from the official repo, run the following:

Alternatively, you can clone the repo to your node_modules directory and run npm install inside the cloned repo.

2. Adding gradle dependencies #

Add gradle-download-task as dependency in android/build.gradle:

3. Adding the :ReactAndroid project #

Add the :ReactAndroid project in android/settings.gradle:

Modify your android/app/build.gradle to use the :ReactAndroid project instead of the pre-compiled library, e.g. - replace compile 'com.facebook.react:react-native:+' with compile project(':ReactAndroid'):

4. Making 3rd-party modules use your fork #

If you use 3rd-party React Native modules, you need to override their dependencies so that they don't bundle the pre-compiled library. Otherwise you'll get an error while compiling - Error: more than one library with package name 'com.facebook.react'.

Modify your android/app/build.gradle, and add:

Building from Android Studio #

From the Welcome screen of Android Studio choose "Import project" and select the android folder of your app.

You should be able to use the Run button to run your app on a device. Android Studio won't start the packager automatically, you'll need to start it by running npm start on the command line.

Additional notes #

Building from source can take a long time, especially for the first build, as it needs to download ~200 MB of artifacts and compile the native code. Every time you update the react-native version from your repo, the build directory may get deleted, and all the files are re-downloaded. To avoid this, you might want to change your build directory path by editing the ~/.gradle/init.gradle file:

Testing #

If you made changes to React Native and submit a pull request, all tests will run on your pull request automatically. To run the tests locally, see Testing.

Troubleshooting #

Gradle build fails in ndk-build. See the section about local.properties file above.