UIScreenEdgePanGestureRecognizer looks for panning (dragging) gestures that start near an edge of the screen. The system uses screen edge gestures in some cases to initiate view controller transitions. You can use this class to replicate the same gesture behavior for your own actions.
After creating a screen edge pan gesture recognizer, assign an appropriate value to the
edges property before attaching the gesture recognizer to your view. You use this property to specify from which edges the gesture may start. This gesture recognizer ignores any touches beyond the first touch.
The acceptable starting edges for the gesture.
var edges: UIRectEdge
@property(readwrite, nonatomic, assign) UIRectEdge edges
The edges you specify are always relative to the app’s current interface orientation. This behavior ensures that the gestures always occur from the same place in your user interface, regardless of the device’s current orientation.
Available in iOS 7.0 and later.