Automatic Android APK Signing

Posted on December 20, 2016 in Development

Declaring Signing credentials

Never put your signing apk credentials in github or any public sharable place. Always put them in a non-committable file. I'll be using local gradle installations's gradle.properties to store signing creds. It sits at root level of your project. Alternately, you can also use /.gradle/.gradle.properties.

Declaring release apk credentials

RELEASE_KEYSTORE_FILE={path to your release keystore}
RELEASE_KEYSTORE_PASSWORD=*****
RELEASE_KEYSTORE_ALIAS=*****

Declaring debug apk credentials

DEBUG_KEYSTORE_FILE={path to your debug keystore}
DEBUG_KEYSTORE_PASSWORD=*****
DEBUG_KEYSTORE_ALIAS=*****

Note: There is no quotes around file path, passwords and alias.

Loading variables from gradle.properties into build.gradle

Properties properties = new Properties()
properties.load(project.rootProject.file('gradle.properties').newDataInputStream())
def RELEASE_KEYSTORE_FILE = properties.getProperty('RELEASE_KEYSTORE_FILE')
def RELEASE_KEYSTORE_PASSWORD = properties.getProperty('RELEASE_KEYSTORE_PASSWORD')
def RELEASE_KEYSTORE_ALIAS = properties.getProperty('RELEASE_KEYSTORE_ALIAS')

def DEBUG_KEYSTORE_FILE = properties.getProperty('DEBUG_KEYSTORE_FILE')
def DEBUG_KEYSTORE_PASSWORD = properties.getProperty('DEBUG_KEYSTORE_PASSWORD')
def DEBUG_KEYSTORE_ALIAS = properties.getProperty('DEBUG_KEYSTORE_ALIAS')

Defining Signing config in `build.gradle`

signingConfigs {
        debug {
            storeFile file(new File(DEBUG_KEYSTORE_FILE))
            storePassword DEBUG_KEYSTORE_PASSWORD
            keyAlias DEBUG_KEY_ALIAS
            keyPassword DEBUG_KEY_PASSWORD
        }

        release {
            storeFile file(new File(RELEASE_KEYSTORE_FILE))
            storePassword RELEASE_KEYSTORE_PASSWORD
            keyAlias RELEASE_KEY_ALIAS
            keyPassword RELEASE_KEY_PASSWORD
        }
    }

Note: Order of defining buildTypes block and signingConfigs block is very important. signingConfigs comes before buildTypes block.

Putting All together

Full signing configuration in build.gradle will look like this:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "com.myawesomeproject.id"
        minSdkVersion 14
        targetSdkVersion 24
        versionCode 1
        versionName "1.1"
    }

    signingConfigs {
        debug {
            storeFile file(new File(DEBUG_KEYSTORE_FILE))
            storePassword DEBUG_KEYSTORE_PASSWORD
            keyAlias DEBUG_KEY_ALIAS
            keyPassword DEBUG_KEY_PASSWORD
        }

        release {
            storeFile file(new File(RELEASE_KEYSTORE_FILE))
            storePassword RELEASE_KEYSTORE_PASSWORD
            keyAlias RELEASE_KEY_ALIAS
            keyPassword RELEASE_KEY_PASSWORD
        }
    }

    buildTypes {
        debug {
            signingConfig signingConfigs.debug
            minifyEnabled false
        }

        release {
            signingConfig signingConfigs.release
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
} //closing android block


dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
}