Simple-Gallery/app/build.gradle

apply plugin: 'com.android.application'
apply plugin: 'android-apt'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.simplemobiletools.gallery"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }

    signingConfigs {
        release
    }

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

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.3.0'
    compile 'com.android.support:design:23.3.0'
    compile 'com.github.bumptech.glide:glide:3.7.0'
    compile 'com.davemorrissey.labs:subsampling-scale-image-view:3.4.1'
    compile 'com.jakewharton:butterknife:8.0.1'

    apt 'com.jakewharton:butterknife-compiler:8.0.1'
}

def Properties props = new Properties()
def propFile = new File('signing.properties')
if (propFile.canRead()) {
    props.load(new FileInputStream(propFile))

    if (props != null && props.containsKey('STORE_FILE') && props.containsKey('STORE_PASSWORD') &&
            props.containsKey('KEY_ALIAS') && props.containsKey('KEY_PASSWORD')) {
        android.signingConfigs.release.storeFile = file(props['STORE_FILE'])
        android.signingConfigs.release.storePassword = props['STORE_PASSWORD']
        android.signingConfigs.release.keyAlias = props['KEY_ALIAS']
        android.signingConfigs.release.keyPassword = props['KEY_PASSWORD']
    } else {
        println 'signing.properties found but some entries are missing'
        android.buildTypes.release.signingConfig = null
    }
} else {
    println 'signing.properties not found'
    android.buildTypes.release.signingConfig = null
}