update:
running “gradle --offline” showed a new error message
FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring project ':app'.
> Failed to find target with hash string 'android-17' in: /opt/android-sdk-26
which pointed to some install issue with sdk-26 because
# ./sdkmanager --uninstall platforms\;android-17
Warning: Unable to find package platforms;android-17
done
so I’ve scratched and reinstalled sdk-26 and now – drum roll – gradle works fine and builds the sample project apk!!
still, without “–offline” I get those warnings
Warning: Failed to connect to host: https://dl.google.com/android/repository/addons_list-3.xml
Warning: Failed to connect to host: https://dl.google.com/android/repository/addons_list-2.xml
Warning: Failed to connect to host: https://dl.google.com/android/repository/addons_list-1.xml
Warning: Failed to download any source lists!
Warning: java.net.UnknownHostException: dl.google.com
which IMHO should not happen for my setup ?!
but never mind – it’s building again… 