The step repo: https://github.com/bitrise-steplib/steps-install-missing-android-tools
This new step will analyze your Android (gradle) project, determine the desired compile sdk version (android-xx package), build tools version (build-tools-x.x.x package) and if google play services or support library is used and also installs the missing tools.
How / where to add this Step to your existing Workflow:
You can add this step (Install missing Android tools) right after the Git Clone step in your workflow, and that’s all!
If you have a recent Android project, where GRADLE_BUILD_FILE_PATH is set as an App Env Var (the automatic bitrise.io scanner adds this environment variable for Android projects automatically for quite some time now), you don’t have to set anything else!
If your project does not have the GRADLE_BUILD_FILE_PATH App Env Var then you can either set this to the relative path of the root build.gradle file (e.g.: ./MyAndroidProject/build.gradle if your android project is in a sub directory called MyAndroidProject inside your repository, or simply ./build.gradle if build.gradle is in your repository’s root) as an App Env Var, or simply specify the path for this new step’s Path to the root build.gradle file input. Or, alternatively, register your repository again on bitrise.io, to get an up to date, auto-generated base workflow! 
