https://situbondoprogrammer.blogspot.com/2021/10/latest-gitlab-ci-script-android-studio.html (SDK 30+)

gitlab-ci.yml

# To contribute improvements to CI/CD templates, please follow the Development guide at:
# https://docs.gitlab.com/ee/development/cicd/templates.html
# This specific template is located at:
# https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/ci/templates/Android.gitlab-ci.yml

# Read more about this script on this blog post https://about.gitlab.com/2018/10/24/setting-up-gitlab-ci-for-android-projects/, by Jason Lenny
# If you are interested in using Android with FastLane for publishing take a look at the Android-Fastlane template.

image: openjdk:11-jdk

variables:

  # ANDROID_COMPILE_SDK is the version of Android you're compiling with.
  # It should match compileSdkVersion.
  ANDROID_COMPILE_SDK: "30"

  # ANDROID_BUILD_TOOLS is the version of the Android build tools you are using.
  # It should match buildToolsVersion.
  ANDROID_BUILD_TOOLS: "30.0.3"

  # It's what version of the command line tools we're going to download from the official site.
  # Official Site-> https://developer.android.com/studio/index.html
  # There, look down below at the cli tools only, sdk tools package is of format:
  #        commandlinetools-os_type-ANDROID_SDK_TOOLS_latest.zip
  # when the script was last modified for latest compileSdkVersion, it was which is written down below
  ANDROID_SDK_TOOLS: "7583922"

# Packages installation before running script
before_script:
  - apt-get --quiet update --yes
  - apt-get --quiet install --yes wget tar unzip lib32stdc++6 lib32z1

  # Setup path as ANDROID_SDK_ROOT for moving/exporting the downloaded sdk into it
  - export ANDROID_SDK_ROOT="${PWD}/android-home"
  # Create a new directory at specified location
  - install -d $ANDROID_SDK_ROOT
  # Here we are installing androidSDK tools from official source,
  # (the key thing here is the url from where you are downloading these sdk tool for command line, so please do note this url pattern there and here as well)
  # after that unzipping those tools and
  # then running a series of SDK manager commands to install necessary android SDK packages that'll allow the app to build
  - wget --output-document=$ANDROID_SDK_ROOT/cmdline-tools.zip https://dl.google.com/android/repository/commandlinetools-linux-${ANDROID_SDK_TOOLS}_latest.zip
  # move to the archive at ANDROID_SDK_ROOT
  - pushd $ANDROID_SDK_ROOT
  - unzip -d cmdline-tools cmdline-tools.zip
  - pushd cmdline-tools
  # since commandline tools version 7583922 the root folder is named "cmdline-tools" so we rename it if necessary
  - mv cmdline-tools tools || true
  - popd
  - popd
  - export PATH=$PATH:${ANDROID_SDK_ROOT}/cmdline-tools/tools/bin/

  # Nothing fancy here, just checking sdkManager version
  - sdkmanager --version

  # use yes to accept all licenses
  - yes | sdkmanager --licenses || true
  - sdkmanager "platforms;android-${ANDROID_COMPILE_SDK}"
  - sdkmanager "platform-tools"
  - sdkmanager "build-tools;${ANDROID_BUILD_TOOLS}"

  # Not necessary, but just for surity
  - chmod +x ./gradlew

# Basic android and gradle stuff
# Check linting
lintDebug:
  interruptible: true
  stage: build
  script:
    - ./gradlew -Pci --console=plain :app:lintDebug -PbuildDir=lint

# Make Project
assembleDebug:
  interruptible: true
  stage: build
  script:
    - ./gradlew assembleDebug
  artifacts:
    paths:
      - app/build/outputs/

# Run all tests, if any fails, interrupt the pipeline(fail it)
debugTests:
  interruptible: true
  stage: test
  script:
    - ./gradlew -Pci --console=plain :app:testDebug