Describes the elements that can be affected by the animator. Classes that implement the methods of this interface can be controlled by the UIKit.UIDynamicAnimator.

iOS 7 introduced UI Dynamics, which provides physics-based animation for UI elements. The overall coordination of UI Dynamics is performed by a UIKit.UIDynamicAnimator, which holds references to a number of UIKit.UIDynamicBehaviors, which define behaviors such as gravity, pushing, and collision detection. Each UIKit.UIDynamicBehavior holds references to some amount of UIKit.IUIDynamicItems, which represent the objects to which the physics model is applied.

While this class contains the full protocol definition, and allows for users to override the methods manually in subclasses, if you want to create your own items that can be animated by the physics engine, all you have to do is implement the UIKit.IUIDynamicItem interface in your object.

Two classes that implement UIKit.IUIDynamicItem are UIKit.UIView and UIKit.UICollectionViewLayoutAttributes.