Tôi rất thích chia sẻ cách tiếp cận của mình vì tất cả các cách tiếp cận khác đều dựa trên một trong hai UIGestureRecognizerDelegatehoặc phân lớp UIPanGestureRecognizer.
Cách tiếp cận của tôi dựa trên thời gian chạy và swizzling. Tôi không chắc chắn 100% về phương pháp này, nhưng bạn có thể tự kiểm tra và cải thiện nó.
Đặt hướng của bất kỳ UIPanGestureRecognizerchỉ với một dòng mã:
UITableView().panGestureRecognizer.direction = UIPanGestureRecognizer.Direction.vertical
sử dụng pod 'UIPanGestureRecognizerDirection'hoặc mã:
public extension UIPanGestureRecognizer {
override open class func initialize() {
super.initialize()
guard self === UIPanGestureRecognizer.self else { return }
func replace(_ method: Selector, with anotherMethod: Selector, for clаss: AnyClass) {
let original = class_getInstanceMethod(clаss, method)
let swizzled = class_getInstanceMethod(clаss, anotherMethod)
switch class_addMethod(clаss, method, method_getImplementation(swizzled), method_getTypeEncoding(swizzled)) {
case true:
class_replaceMethod(clаss, anotherMethod, method_getImplementation(original), method_getTypeEncoding(original))
case false:
method_exchangeImplementations(original, swizzled)
}
}
let selector1 = #selector(UIPanGestureRecognizer.touchesBegan(_:with:))
let selector2 = #selector(UIPanGestureRecognizer.swizzling_touchesBegan(_:with:))
replace(selector1, with: selector2, for: self)
let selector3 = #selector(UIPanGestureRecognizer.touchesMoved(_:with:))
let selector4 = #selector(UIPanGestureRecognizer.swizzling_touchesMoved(_:with:))
replace(selector3, with: selector4, for: self)
}
@objc private func swizzling_touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
self.swizzling_touchesBegan(touches, with: event)
guard direction != nil else { return }
touchesBegan = true
}
@objc private func swizzling_touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
self.swizzling_touchesMoved(touches, with: event)
guard let direction = direction, touchesBegan == true else { return }
defer {
touchesBegan = false
}
let forbiddenDirectionsCount = touches
.flatMap({ ($0.location(in: $0.view) - $0.previousLocation(in: $0.view)).direction })
.filter({ $0 != direction })
.count
if forbiddenDirectionsCount > 0 {
state = .failed
}
}
}
public extension UIPanGestureRecognizer {
public enum Direction: Int {
case horizontal = 0
case vertical
}
private struct UIPanGestureRecognizerRuntimeKeys {
static var directions = "\(#file)+\(#line)"
static var touchesBegan = "\(#file)+\(#line)"
}
public var direction: UIPanGestureRecognizer.Direction? {
get {
let object = objc_getAssociatedObject(self, &UIPanGestureRecognizerRuntimeKeys.directions)
return object as? UIPanGestureRecognizer.Direction
}
set {
let policy = objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC
objc_setAssociatedObject(self, &UIPanGestureRecognizerRuntimeKeys.directions, newValue, policy)
}
}
fileprivate var touchesBegan: Bool {
get {
let object = objc_getAssociatedObject(self, &UIPanGestureRecognizerRuntimeKeys.touchesBegan)
return (object as? Bool) ?? false
}
set {
let policy = objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC
objc_setAssociatedObject(self, &UIPanGestureRecognizerRuntimeKeys.touchesBegan, newValue, policy)
}
}
}
fileprivate extension CGPoint {
var direction: UIPanGestureRecognizer.Direction? {
guard self != .zero else { return nil }
switch fabs(x) > fabs(y) {
case true: return .horizontal
case false: return .vertical
}
}
static func -(lhs: CGPoint, rhs: CGPoint) -> CGPoint {
return CGPoint(x: lhs.x - rhs.x, y: lhs.y - rhs.y)
}
}