MDCalendar is a calendar-style date picker for iOS 7 (and above) that uses UICollectionView to layout a calendar in the popular "month view" format.
MDCalendar was developed with flexibility in mind and is consequently implemented as a subclass of UIView. This means that a calendar may be instantiated as a subview in an existing view hierarchy or pushed onto a navigation stack as the sole view of a UIViewController. The latter behavior is demonstrated in the MDCalendarDemo project.
One of the philosophies used while designing MDCalendar was to minimize an explicit storage-based model. As a result, the vast majority of date and geometry math is calculated on-the-fly. Caching, particularly for the geometric calculations has been implemented, and MDCalendar has been tested with an endDate of [NSDate distantFuture].
Suppose a view controller called EventDetailsViewController wants to allow users to modify the date of the event using a nice calendar picker. Hmm... let's use MDCalendar for that! EventDetailsViewController is a subclass of UITableViewController and selecting one of the rows should push a calendar on-screen and allow users to modify the eventDate property of the EventDetailsViewController
The advised implementation of this is to create a sparse view controller to display an MDCalendar (see the demo project for an example of how to do that). This view controller, let's call it MDEventCalendarViewController (creative, I know), will be pushed onto the navigation stack.
In the above example, we will need to communicate calendar events back to its parent view controller. In order to do this elegantly, subclass MDCalendarDelegate in MDEventCalendarViewController and expose this protocol, MDEventCalendarDelegate, in the view controller's header. Now, the parent view controller, EventDetailsViewController, can set its delegate: id<MDEventCalendarDelegate>delegate
This delegate will essentially pass messages from MDCalendarDelegate onto the parent view controller. Advantages of subclassing MDCalendarDelegate is that if you were to re-use your sparse view controller it could contain some logic of how to interperet MDCalendarDelegate events.
Version 1.0.0 of MDCalendar features VoiceOver support with proper accessibility labels for each date.