How to create a smooth transition with a view moving to overlay above an activity?

I'm investigating how the author of "inflickr"

https://play.google.com/store/apps/details?id=kr.infli

created the smooth transitions to bring his 'picture info' views above the picture itself. What method did the author use to create this effect?

Regarding Inflikr, there is only one activity involved.

The custom view (in black here) have a gesture detector and on a scroll up it will pull a details's view placed at the bottom (red frame).

The detail's view is transparent, when sliding up it increase alpha on a black shader on the custom view so the white text become readable even on a bright photo.

ps: rendered on device using scalpel

Thanks