gradle signing

// signing.properties
STORE_FILE=../app.jks
STORE_PASSWORD=**pass**
KEY_ALIAS=**key**
KEY_PASSWORD=**pass**


// app.gradle
File propFile = file('signing.properties');
if (propFile.exists()) {
  def Properties props = new Properties()
  props.load(new FileInputStream(propFile))

  if (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 {
    android.buildTypes.release.signingConfig = null
  }
} else {
  android.buildTypes.release.signingConfig = null
}