Apache POI [ https://poi.apache.org/ ]
can be used in the android app. Multidex is needed.
But originally the library works well only with xls files.
To work with xlsx the Apache POI-ooxml is needed.
Also there is [https://github.com/andruhon/android5xlsx]
There is a issue with java.awt
Creating Excel files with C and libxlsxwriter