UISwipeGestureRecognizer每个方向都需要一个。有点奇怪，因为该UISwipeGestureRecognizer.direction属性是选项样式的位掩码，但是每个识别器只能处理一个方向。您可以根据需要将它们全部发送到同一个处理程序，并在那里进行排序，或者将它们发送到不同的处理程序。这是一个实现：

override func viewDidLoad() {
    super.viewDidLoad()

    let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(respondToSwipeGesture))
    swipeRight.direction = .right
    self.view.addGestureRecognizer(swipeRight)

    let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(respondToSwipeGesture))
    swipeDown.direction = .down
    self.view.addGestureRecognizer(swipeDown)
}

@objc func respondToSwipeGesture(gesture: UIGestureRecognizer) {

    if let swipeGesture = gesture as? UISwipeGestureRecognizer {

        switch swipeGesture.direction {
        case .right:
            print("Swiped right")
        case .down:
            print("Swiped down")
        case .left:
            print("Swiped left")
        case .up:
            print("Swiped up")
        default:
            break
        }
    }
}

斯威夫特3：

override func viewDidLoad() {
    super.viewDidLoad()

    let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(self.respondToSwipeGesture))
    swipeRight.direction = UISwipeGestureRecognizerDirection.right
    self.view.addGestureRecognizer(swipeRight)

    let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(self.respondToSwipeGesture))
    swipeDown.direction = UISwipeGestureRecognizerDirection.down
    self.view.addGestureRecognizer(swipeDown)
}

func respondToSwipeGesture(gesture: UIGestureRecognizer) {
    if let swipeGesture = gesture as? UISwipeGestureRecognizer {
        switch swipeGesture.direction {
        case UISwipeGestureRecognizerDirection.right:
            print("Swiped right")
        case UISwipeGestureRecognizerDirection.down:
            print("Swiped down")
        case UISwipeGestureRecognizerDirection.left:
            print("Swiped left")
        case UISwipeGestureRecognizerDirection.up:
            print("Swiped up")
        default:
            break
        }
    }
}