Answer by Kris Roofe for Finding Android SDK on Mac and adding to PATH

The default path of Android SDK is /Users/<username>/Library/Android/sdk, you can refer to this post.

add this to your .bash_profile to add the environment variable

export PATH="/Users/<username>/Library/Android/sdk/tools:/Users/<username>/Library/Android/sdk/build-tools:${PATH}"

Then save the file.

load it

source ./.bash_profile