Android custom gradle properties

This is an example demo for adding gradle properties in a custom gradle properties and for creating multiple gradle property files in Android.

Define some properties in a custom gradle property file, my_credentials.properties at the root directory of the Android project.

#define credential variables here, read it in the project build.gradle, and use it in the app build.gradle
apiId=abcdefg
apiPassword=123456789

In the project gradle.build file, in the buildscript block, read the properties defined in the my_credentials.properties file.

def credentialsProperties = new Properties()
if (file("$rootDir/my_credentials.properties").exists()) {
    file("$rootDir/my_credentials.properties").withInputStream { credentialsProperties.load(it) }
}
ext.credentialsProperties = credentialsProperties

In the app gradle.build file, use properties defined in the above. The following will generate two constants in the BuildConfig.kt

buildConfigField "String", "API_ID", "\"${credentialsProperties.apiId}\""
buildConfigField "String", "API_PASSWORD", "\"${credentialsProperties.apiPassword}\""

The final product of the above, BuildConfig.kt

public final class BuildConfig {
  public static final boolean DEBUG = Boolean.parseBoolean("true");
  public static final String APPLICATION_ID = "com.example.gradle_custom_properties";
  public static final String BUILD_TYPE = "debug";
  public static final String FLAVOR = "";
  public static final int VERSION_CODE = 1;
  public static final String VERSION_NAME = "1.0";
  // Fields from default config.
  public static final String API_ID = "abcdefg";
  public static final String API_PASSWORD = "123456789";
}

Complete example in Github