This Docker image contains the Android SDK and most common packages necessary for building Android apps in a CI tool like GitLab CI. Make sure your CI environment's caching works as expected, this greatly improves the build time, especially if you use multiple build jobs.

A .gitlab-ci.yml with caching of your project's dependencies would look like this:

image: jangrewe/gitlab-ci-android
stages:
- build
before_script:
- export GRADLE_USER_HOME=$(pwd)/.gradle
- chmod +x ./gradlew
cache:
 key: ${CI_PROJECT_ID}
 paths:
 - .gradle/
build:
 stage: build
 script:
 - ./gradlew assembleDebug
 artifacts:
 paths:
 - app/build/outputs/apk/app-debug.apk