Thanks @ScruffR for your answer. Yes, I select the android-app-master folder but only SparkCore folder is listed and imported.
Could it be the version of Eclipse I’m using?
I am using Eclipse Kepler SR2, but SR1 and Juno worked fine, too.
Maybe you remove all android-app projects from your Eclipse Workspace (or create a new Workspace) and also delete (or rename) all files/folders starting with . (e.g. .project, .settings … - but not the .git folder, if present) from the android-app folder and its subfolders and retry importing.