Carefully run the following commands; this will remove Android Studio and its related preferences and library files. This is the best way to completely uninstall Android Studio and prep it for reinstallation, if desired.
Delete Mac Android Studio itself:
rm -Rf /Applications/Android\ Studio.app
rm -Rf ~/Library/Preferences/AndroidStudio*
rm -Rf ~/Library/Preferences/com.google.android.*
rm -Rf ~/Library/Preferences/com.android.*
rm -Rf ~/Library/Application\ Support/AndroidStudio*
rm -Rf ~/Library/Logs/AndroidStudio*
rm -Rf ~/Library/Caches/AndroidStudio*
rm -Rf ~/.AndroidStudio*
Delete all Android Studio projects (optional):
rm -Rf ~/AndroidStudioProjects
Delete Gradle files/cache:
rm -Rf ~/.android
Delete SDK tools:
rm -Rf ~/Library/Android*
That's it. You're done!