在iOS中检测PAN手势的方向

import UIKit

let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePanGesture(_:)))
view.addGestureRecognizer(panGestureRecognizer)

@objc func handlePanGesture(_ gestureRecognizer: UIPanGestureRecognizer) {
    let translation = gestureRecognizer.translation(in: view)
    let direction = getPanDirection(translation: translation)
    switch direction {
    case .up:
        print("向上滑动")
    case .down:
        print("向下滑动")
    case .left:
        print("向左滑动")
    case .right:
        print("向右滑动")
    case .none:
        print("未滑动")
    }
    gestureRecognizer.setTranslation(.zero, in: view)
}

enum PanDirection {
    case up
    case down
    case left
    case right
    case none
}

func getPanDirection(translation: CGPoint) -> PanDirection {
    let x = translation.x
    let y = translation.y
    if x > 0 {
        return .right
    } else if x < 0 {
        return .left
    } else if y > 0 {
        return .down
    } else if y < 0 {
        return .up
    } else {
        return .none
    }
}