Enabling android code obfuscation in react native with R8 and proguard rules

Android-code-obfuscation.md

Android code obfuscation in react native

Enabling R8 code obfuscation:

App > build.gradle

debug {
        signingConfig signingConfigs.debug
    }
    release {
         signingConfig signingConfigs.release
        debuggable false
        minifyEnabled true
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }

Default three proguard rules files are automatically generated in app > build > intermediates > proguard-files

• proguard-android-optimize.txt
• proguard-android.txt
• proguard-defaults.txt

We can choose based on our requirement.

For additional rules we can write below code in app > Proguard-rules.pro

# Add project specific ProGuard rules here.
# By default, the flags in this file are appended to flags specified
# in /usr/local/Cellar/android-sdk/24.3.3/tools/proguard/proguard-android.txt
# You can edit the include path and order by changing the proguardFiles
# directive in build.gradle.
#
# For more details, see
#   http://developer.android.com/guide/developing/tools/proguard.html

# Add any project specific keep options here:
 -assumenosideeffects classandroid.utils.Log{*;}
 -keep class io.invertase.firebase.** { *; }.      ————> Firebase rules are added additionally
 -dontwarn io.invertase.firebase.**
 -keepattributes *Annotation*
 -keepclassmembers class ** {
 @org.greenrobot.eventbus.Subscribe <methods>;
 }
 -keep enum org.greenrobot.eventbus.ThreadMode { *; }

For running : If below is not there in app > build.gradle, please add

// applicationVariants are e.g. debug, release
applicationVariants.all { variant ->
    variant.outputs.each { output ->
        // For each separate APK per architecture, set a unique version code as described here:
        // https://developer.android.com/studio/build/configure-apk-splits.html
        def versionCodes = ["armeabi-v7a": 1, "x86": 2, "arm64-v8a": 3, "x86_64": 4]
        def abi = output.getFilter(OutputFile.ABI)
        if (abi != null) {  // null for the universal-debug, universal-release variants
            output.versionCodeOverride =
                    versionCodes.get(abi) * 1048576 + defaultConfig.versionCode
        }

    }
}

By default react-native run-android builds the apk in debug mode but R8 obfuscation doesn’t work in debug.

Running in release mode:

react-native run-android --variant=release

Building the apk in release mode:

Cd android
./gradlew assembleRelease

---

For enabling code obfuscation in proguard instead of R8.

	debug {
		signingConfig signingConfigs.debug
	}
	release {
		signingConfig signingConfigs.release
		debuggable false
		minifyEnabled true
		useProguard true         ———> enables proguard
		proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
	}