DirectedPanGestureRecognizer
DirectedPanGestureRecognizer is a UIPanGestureRecognizer subclass providing a richer API for working with pan gestures in Swift 3.
It's based on my older CXSwipeGestureRecognizer library. It doesn't strictly deprecate that project – while it's mostly just a straight rewrite in Swift, some of the more opinionated features have been removed.
Installation:
pod 'DirectedPanGestureRecognizer', '~> 1.0'Usage:
let gestureRecognizer = DirectedPanGestureRecognizer()
gestureRecognizer.delegate = self
view.addGestureRecognizer(gestureRecognizer)Features:
✓ Keeps track of the initial state of the gesture:
if (gestureRecognizer.initialDirection == .up) {
if (gestureRecognizer.direction == .down) {
print("Gesture recognizer started swiping upwards and then changed direction")
}
}✓ Enforce the gesture's starting direction:
func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
switch gestureRecognizer {
case let panGestureRecognizer as DirectedPanGestureRecognizer where panGestureRecognizer == self.panGestureRecognizer:
return panGestureRecognizer.direction == .left
default:
return true
}
}✓ Delegate protocol methods for start, update, cancel, and finish events:
func directedPanGestureRecognizer(didStart gestureRecognizer: DirectedPanGestureRecognizer) {
print("Gesture recognizer started")
}
func directedPanGestureRecognizer(didUpdate gestureRecognizer: DirectedPanGestureRecognizer) {
print("Gesture recognizer updated")
}
func directedPanGestureRecognizer(didCancel gestureRecognizer: DirectedPanGestureRecognizer) {
print("Gesture recognizer cancelled")
}
func directedPanGestureRecognizer(didFinish gestureRecognizer: DirectedPanGestureRecognizer) {
print("Gesture recognizer finished")
}✓ Convenience methods for location, direction, translation, and velocity:
let location = gestureRecognizer.location // CGPoint?
let direction = gestureRecognizer.direction // DirectedPanGestureRecognizer.Direction?
let translation = gestureRecognizer.translation(inDirection: .right) // CGFloat
let velocity = gestureRecognizer.velocity(inDirection: .right) // CGFloat✓ IBDesignable parameters for enforcing a minimum translation and velocity:
gestureRecognizer.minimumTranslation = 64.0
gestureRecognizer.minimumVelocity = 256.0