Is it possible to use Affectiva SDK to detect a "real face" on Android? By real face I mean that the user actually taking a selfi, not pointing front camera on a static photo.
The Affectiva SDK doesn't inherently distinguish between "real" faces and static photos, so it won't, for example, exclude static photos from its analysis. The client application will get results back from the SDK for both kinds of faces.
That being said, a client application could potentially exploit the fact that the expression metrics reported by the SDK for the static photo would be pretty static themselves, while that would be much less likely for a "real" face, and use that to infer that the static photo is not a "real" face.