Ceph is very robust for keeping data, beside using cephfs or exporting rbd. It is not too easy to access object directly with a client, let alone mobile. By using Rados gateway, android client can easily using S3/Swift http/s request to read object data from the internet.
It is a simple idea to use an existing open source android FileManager e.g. https://github.com/arpitkh96/AmazeFileManager Then add S3 library from Amazon, or Swift java library to use the Rados gateway configuration. The bucket will be view as Directory. The object will be view as File.
The current plan is to just create a read only example.
Bonus : once the android client is done, the read object is likely to be Movie and Pictures. It could possible to provide a transcoding service from the ARM setup top box gateway since most of them has encoder and decoder build in nowaday. So you mobile can request a Full HD source object and being transcoded to 480p.
This project is one of its kind!