How make an view like Periscope's Broadcast View?

All

i want to make an view like 'Periscope' brocadcast View，it's use self.presentedViewController to show this view... and i get some trouble. Like This: it's full screen broadcast view, user can pull top to bottom

when i pull top to bottom, it's will animated show top view, like this image

finish, this view must like this, and user can pull bottom to top for animated hide top view

does anyone can help me.... thx