A Plugin for Signing Android Builds on Expo Prebuild

Effortlessly configure signing for Android builds in Expo projects during the prebuild process.

• Step 1: Updates the gradle.properties file to include signing configurations.
• Step 2: Modifies the build.gradle file to switch from debug signing to release signing.
• Step 3: Adds a release signing block to the build.gradle file if it doesn’t already exist.
• Step 4: Copies the keystore file to the android > app directory for signing during the build process.

• Expo Local App Production Guide
• Continuous Native Generation in Expo
• React Native Documentation: Generating an Upload Key

• Automatic Configuration: Updates android > gradle.properties to include the specified signing properties if they don’t already exist.
• Signing Configuration: Replaces signingConfig signingConfigs.debug with signingConfig signingConfigs.release under android.buildTypes.release in android > app > build.gradle.
• Release Block Addition: Adds the release block with the specified properties to android.signingConfigs in android > app > build.gradle if it doesn’t exist.
• Keystore File Handling: Copies the specified .keystore file (defined by store_file.value) from the keystorePath to the android > app folder.

Before using expo-signed, generate a private signing key and follow these steps:

1. Generate a Key:
   Use keytool to create a private signing key. Follow the instructions provided in the React Native documentation on signed APKs.

2. Place the Keystore File:
   Add the generated keystore file to your project directory.

To install and configure the plugin:

Run the following command to install the plugin in your Expo project:

npx expo install expo-signed

• Place the .keystore file in your project, and set the folder path (keystorePath) and file name (store_file.value) in the configuration.

Add the plugin configuration to your app.json as follows:

"plugins": [
    ...
    [
        "expo-signed",
        {
            "store_file": {
                "key": "MY_UPLOAD_STORE_FILE",
                "value": "my-upload-key.keystore"
            },
            "key_alias": {
                "key": "MY_UPLOAD_KEY_ALIAS",
                "value": "my-key-alias"
            },
            "store_password": {
                "key": "MY_UPLOAD_STORE_PASSWORD",
                "value": "************"
            },
            "key_password": {
                "key": "MY_UPLOAD_KEY_PASSWORD",
                "value": "************"
            },
            "keystorePath": "./src/assets"
        }
    ],
    ...
]

By following the above steps, you’ll be able to sign your Android builds seamlessly with expo-signed.