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.
Android
Prerequisites
Assuming you have the Android SDK installed, run android
to open the Android SDK Manager.
Make sure you have the following installed:
- Android SDK version 28 (compileSdkVersion in
build.gradle
) - SDK build tools version 28.0.3 (buildToolsVersion in
build.gradle
) - Android Support Repository >= 28 (for Android Support Library)
- 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:
export ANDROID_SDK=/Users/your_unix_name/android-sdk-macosx
export ANDROID_NDK=/Users/your_unix_name/android-ndk/android-ndk-r17c
Step 2: Create a local.properties
file in the android
directory of your react-native app with the following contents:
Example:
sdk.dir=/Users/your_unix_name/android-sdk-macosx
ndk.dir=/Users/your_unix_name/android-ndk/android-ndk-r17c
Download links for Android NDK
- Mac OS (64-bit) - http://dl.google.com/android/repository/android-ndk-r17c-darwin-x86_64.zip
- Linux (64-bit) - http://dl.google.com/android/repository/android-ndk-r17c-linux-x86_64.zip
- Windows (64-bit) - http://dl.google.com/android/repository/android-ndk-r17c-windows-x86_64.zip
- Windows (32-bit) - http://dl.google.com/android/repository/android-ndk-r17c-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:
npm install --save github:facebook/react-native#master
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
:
...
dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
classpath 'de.undercouch:gradle-download-task:3.4.3'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
...
:ReactAndroid
project
3. Adding the Add the :ReactAndroid
project in android/settings.gradle
:
...
include ':ReactAndroid'
project(':ReactAndroid').projectDir = new File(
rootProject.projectDir, '../node_modules/react-native/ReactAndroid')
...
Modify your android/app/build.gradle
to use the :ReactAndroid
project instead of the pre-compiled library, e.g. - replace implementation 'com.facebook.react:react-native:+'
with implementation project(':ReactAndroid')
:
...
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}'
implementation 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:
configurations.all {
exclude group: 'com.facebook.react', module: 'react-native'
}
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:
gradle.projectsLoaded {
rootProject.allprojects {
buildDir = "/path/to/build/directory/${rootProject.name}/${project.name}"
}
}
Troubleshooting
Gradle build fails in ndk-build
. See the section about local.properties
file above.
Testing your Changes
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 your Changes.
Making your changes available
See the Publishing your own version of react native for several options to make your changes available for your and other app projects.