[Conceptual][Photos app] Floating toolbar "Years""Months""Days" at the bottom - Best way to implement floating toolbar?

Any ideas on how to go about implementing floating Segmented toolbar like in Photos app on the Photos tab?

What view hierarchy should you add the toolbar subview to? (UICollectionView, UINavigationController's view, Tab Bar's view, custom UIWindow]? Is there some special API for this or just plain addSubview?