UIPanGestureRecognizer - Apenas vertical ou horizontal

Eu tenho uma visão que tem UIPanGestureRecognizerque arrastar a visão verticalmente. Portanto, no retorno de chamada do reconhecedor, apenas atualizo a coordenada y para movê-lo. A super visão dessa visão, tem uma UIPanGestureRecognizerque arrastará a visão horizontalmente, apenas atualizando a coordenada x.

O problema é que o primeiro UIPanGestureRecognizeré levar o evento para mover a vista verticalmente, então não posso usar o gesto de superview.

eu tentei

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
 shouldRecognizeSimultaneouslyWithGestureRecognizer:
                            (UIGestureRecognizer *)otherGestureRecognizer;

e ambos vão funcionar, mas eu não quero isso. Quero que a horizontal seja detectada apenas se o movimento for claramente horizontal. Portanto, seria ótimo se UIPanGestureRecognizertivesse uma propriedade direction.

Como posso conseguir esse comportamento? Acho os documentos muito confusos, então talvez alguém possa explicar melhor aqui.

Basta fazer isso no reconhecedor de gesto de panorâmica vertical, ele funciona para mim:

- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)panGestureRecognizer {
    CGPoint velocity = [panGestureRecognizer velocityInView:someView];
    return fabs(velocity.y) > fabs(velocity.x);
}

E para Swift:

func gestureRecognizerShouldBegin(_ gestureRecognizer: UIPanGestureRecognizer) -> Bool {
    let velocity = gestureRecognizer.velocity(in: someView)
    return abs(velocity.x) > abs(velocity.y)
}

Criei uma solução com subclasse como na resposta que o @LocoMike forneceu, mas usei o mecanismo de detecção mais eficaz pela velocidade inicial, conforme fornecido pelo @Hejazi. Também estou usando o Swift, mas isso deve ser fácil de traduzir para Obj-C, se desejado.

Vantagens sobre outras soluções:

• Mais simples e concisa do que outras soluções de subclasse. Nenhum estado adicional para gerenciar.
• A detecção de direção ocorre antes do envio da ação Iniciada, para que o seletor de gesto de movimento panorâmico não receba mensagens se a direção errada for passada.
• Depois que a direção inicial é determinada, a lógica da direção não é mais consultada. Isso resulta no comportamento geralmente desejado de ativar o reconhecedor se a direção inicial estiver correta, mas não cancela o gesto após o início, se o dedo do usuário não viajar perfeitamente ao longo da direção.

Aqui está o código:

import UIKit.UIGestureRecognizerSubclass

enum PanDirection {
    case vertical
    case horizontal
}

class PanDirectionGestureRecognizer: UIPanGestureRecognizer {

    let direction: PanDirection

    init(direction: PanDirection, target: AnyObject, action: Selector) {
        self.direction = direction
        super.init(target: target, action: action)
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesMoved(touches, with: event)

        if state == .began {
            let vel = velocity(in: view)
            switch direction {
            case .horizontal where fabs(vel.y) > fabs(vel.x):
                state = .cancelled
            case .vertical where fabs(vel.x) > fabs(vel.y):
                state = .cancelled
            default:
                break
            }
        }
    }
}

Exemplo de uso:

let panGestureRecognizer = PanDirectionGestureRecognizer(direction: .horizontal, target: self, action: #selector(handlePanGesture(_:)))
panGestureRecognizer.cancelsTouchesInView = false
self.view.addGestureRecognizer(panGestureRecognizer)

func handlePanGesture(_ pan: UIPanGestureRecognizer) {
    let percent = max(pan.translation(in: view).x, 0) / view.frame.width

    switch pan.state {
    case .began:
    ...
}

Eu descobri isso criando uma subclasse de UIPanGestureRecognizer

DirectionPanGestureRecognizer:

#import <Foundation/Foundation.h>
#import <UIKit/UIGestureRecognizerSubclass.h>

typedef enum {
    DirectionPangestureRecognizerVertical,
    DirectionPanGestureRecognizerHorizontal
} DirectionPangestureRecognizerDirection;

@interface DirectionPanGestureRecognizer : UIPanGestureRecognizer {
    BOOL _drag;
    int _moveX;
    int _moveY;
    DirectionPangestureRecognizerDirection _direction;
}

@property (nonatomic, assign) DirectionPangestureRecognizerDirection direction;

@end

DirectionPanGestureRecognizer.m:

#import "DirectionPanGestureRecognizer.h"

int const static kDirectionPanThreshold = 5;

@implementation DirectionPanGestureRecognizer

@synthesize direction = _direction;

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];
    if (self.state == UIGestureRecognizerStateFailed) return;
    CGPoint nowPoint = [[touches anyObject] locationInView:self.view];
    CGPoint prevPoint = [[touches anyObject] previousLocationInView:self.view];
    _moveX += prevPoint.x - nowPoint.x;
    _moveY += prevPoint.y - nowPoint.y;
    if (!_drag) {
        if (abs(_moveX) > kDirectionPanThreshold) {
            if (_direction == DirectionPangestureRecognizerVertical) {
                self.state = UIGestureRecognizerStateFailed;
            }else {
                _drag = YES;
            }
        }else if (abs(_moveY) > kDirectionPanThreshold) {
            if (_direction == DirectionPanGestureRecognizerHorizontal) {
                self.state = UIGestureRecognizerStateFailed;
            }else {
                _drag = YES;
            }
        }
    }
}

- (void)reset {
    [super reset];
    _drag = NO;
    _moveX = 0;
    _moveY = 0;
}

@end

Isso só acionará o gesto se o usuário começar a arrastar o comportamento selecionado. Defina a propriedade direction como um valor correto e está tudo pronto.

Tentei restringir a área válida horizontalmente com o UIPanGestureRecognizer.

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {

        UIPanGestureRecognizer *panGesture = (UIPanGestureRecognizer *)gestureRecognizer;
        CGPoint velocity = [panGesture velocityInView:panGesture.view];

        double radian = atan(velocity.y/velocity.x);
        double degree = radian * 180 / M_PI;

        double thresholdAngle = 20.0;
        if (fabs(degree) > thresholdAngle) {
            return NO;
        }
    }
    return YES;
}

Em seguida, apenas deslizar horizontalmente dentro do grau thresholdAngle pode disparar esse gesto de panorâmica.

Resposta Swift 3.0: apenas lida com o gesto vertical

    override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
    if let pan = gestureRecognizer as? UIPanGestureRecognizer {
        let velocity = pan.velocity(in: self)
        return fabs(velocity.y) > fabs(velocity.x)
    }
    return true

}

A seguinte solução resolveu meu problema:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    if ([gestureRecognizer.view isEqual:self.view] && [otherGestureRecognizer.view isEqual:self.tableView]) {
        return NO;
    }
    return YES;
}

Na verdade, basta verificar se o pan está na visualização principal ou no tableView.

Swift 3 versão da resposta de Lee para os preguiçosos

import UIKit
import UIKit.UIGestureRecognizerSubclass

enum PanDirection {
    case vertical
    case horizontal
}

class UIPanDirectionGestureRecognizer: UIPanGestureRecognizer {

    let direction : PanDirection

    init(direction: PanDirection, target: AnyObject, action: Selector) {
        self.direction = direction
        super.init(target: target, action: action)
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesMoved(touches, with: event)

        if state == .began {

            let vel = velocity(in: self.view!)
            switch direction {
            case .horizontal where fabs(vel.y) > fabs(vel.x):
                state = .cancelled
            case .vertical where fabs(vel.x) > fabs(vel.y):
                state = .cancelled
            default:
                break
            }
        }
    }
}

Peguei a resposta de Lee Goodrich e a estendi, pois precisava especificamente de uma única direção. Use-o assim:let pan = PanDirectionGestureRecognizer(direction: .vertical(.up), target: self, action: #selector(handleCellPan(_:)))

Também adicionei alguns comentários para tornar um pouco mais claro quais decisões estão realmente sendo tomadas.

import UIKit.UIGestureRecognizerSubclass

enum PanVerticalDirection {
    case either
    case up
    case down
}

enum PanHorizontalDirection {
    case either
    case left
    case right
}

enum PanDirection {
    case vertical(PanVerticalDirection)
    case horizontal(PanHorizontalDirection)
}

class PanDirectionGestureRecognizer: UIPanGestureRecognizer {

    let direction: PanDirection

    init(direction: PanDirection, target: AnyObject, action: Selector) {
        self.direction = direction
        super.init(target: target, action: action)
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesMoved(touches, with: event)

        if state == .began {
            let vel = velocity(in: view)
            switch direction {

            // expecting horizontal but moving vertical, cancel
            case .horizontal(_) where fabs(vel.y) > fabs(vel.x):
                state = .cancelled

            // expecting vertical but moving horizontal, cancel
            case .vertical(_) where fabs(vel.x) > fabs(vel.y):
                state = .cancelled

            // expecting horizontal and moving horizontal
            case .horizontal(let hDirection):
                switch hDirection {

                    // expecting left but moving right, cancel
                    case .left where vel.x > 0: state = .cancelled

                    // expecting right but moving left, cancel
                    case .right where vel.x < 0: state = .cancelled
                    default: break
                }

            // expecting vertical and moving vertical
            case .vertical(let vDirection):
                switch vDirection {
                    // expecting up but moving down, cancel
                    case .up where vel.y > 0: state = .cancelled

                    // expecting down but moving up, cancel
                    case .down where vel.y < 0: state = .cancelled
                    default: break
                }
            }
        }
    }
}

Você pode encontrar a direção arrastando no UIViewmeio UIPanGestureRecognizer. Por favor, siga o código.

 - (void)viewDidLoad {
    [super viewDidLoad];
    flipFoward = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(doFlipForward:)];
    [flipFoward setMaximumNumberOfTouches:1];
    [flipFoward setMinimumNumberOfTouches:1];
    [flipFoward setDelegate:self];
    [self.view addGestureRecognizer:flipFoward];
    flipBack = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(doFlipBack:)];
    [flipBack setMaximumNumberOfTouches:1];
    [flipBack setMinimumNumberOfTouches:1];
    [flipBack setDelegate:self];
    [self.view addGestureRecognizer:flipBack];
}

#pragma mark -
#pragma mark RESPONDER

-(void)doFlipForward:(UIGestureRecognizer *)aGestureRecognizer{
    NSLog(@"doFlipForward");
    if([(UIPanGestureRecognizer*)aGestureRecognizer state] == UIGestureRecognizerStateBegan) {
        NSLog(@"UIGestureRecognizerStateBegan");
    }
    if([(UIPanGestureRecognizer*)aGestureRecognizer state] == UIGestureRecognizerStateChanged) {
        NSLog(@"UIGestureRecognizerStateChanged");
    }
    if([(UIPanGestureRecognizer*)aGestureRecognizer state] == UIGestureRecognizerStateEnded) {
        NSLog(@"UIGestureRecognizerStateEnded");
    }
}

-(void)doFlipBack:(UIGestureRecognizer *)aGestureRecognizer{
    NSLog(@"doFlipBack");
    if([(UIPanGestureRecognizer*)aGestureRecognizer state] == UIGestureRecognizerStateBegan) {
        NSLog(@"UIGestureRecognizerStateBegan1");
    }
    if([(UIPanGestureRecognizer*)aGestureRecognizer state] == UIGestureRecognizerStateChanged) {
        NSLog(@"UIGestureRecognizerStateChanged1");
    }
    if([(UIPanGestureRecognizer*)aGestureRecognizer state] == UIGestureRecognizerStateEnded) {
        NSLog(@"UIGestureRecognizerStateEnded1");
    }
}

#pragma mark -
#pragma mark DELEGATE

-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer{
    CGSize size = [self.view bounds].size;
    CGFloat touchX = [gestureRecognizer locationInView:self.view].x;
    if((gestureRecognizer == flipFoward) 
       && touchX >= (size.width - 88.0f))
    {
        return YES;
    }
    if((gestureRecognizer == flipBack)
       && touchX <= 88.0f)
    {
        return YES;
    }
    return NO;
}

Swift 4.2

A solução é apenas para apoiar o gesto de panorâmica verticalmente, igual à horizontal.

let pan = UIPanGestureRecognizer(target: self, action: #selector(test1))
pan.cancelsTouchesInView = false
panView.addGestureRecognizer(pan)

Solução 1 :

@objc func panAction(pan: UIPanGestureRecognizer) {

        let velocity = pan.velocity(in: panView)
        guard abs(velocity.y) > abs(velocity.x) else {
            return
        }
}

Solução 2:

  [UISwipeGestureRecognizer.Direction.left, .right].forEach { direction in
        let swipe = UISwipeGestureRecognizer(target: self, action: #selector(swipeAction))
        swipe.direction = direction
        panView.addGestureRecognizer(swipe)
        pan.require(toFail: swipe)
    }

Em seguida, o gesto de furto engolirá o gesto de pan. Claro, você não precisa fazer nada swipeAction.

Aqui está como eu resolvi:

Primeiro, ativei o reconhecimento simultâneo do PanGesture.

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {

return YES;

Em seguida, isole os gestos de deslocamento horizontal e vertical (o acumulador é a propriedade NSMutableArray):

- (void)verticalPan :(UIPanGestureRecognizer *) sender {

CGPoint touch  = [sender translationInView:self];
NSValue *value = [NSValue valueWithCGPoint:touch];
[accumulator addObject:value];

int firstXObjectValue = (int)[[accumulator objectAtIndex:0] CGPointValue].x ;
int lastXObjectValue =  (int)[[accumulator lastObject] CGPointValue].x;

int firstYObjectValue = (int)[[accumulator objectAtIndex:0] CGPointValue].y;
int lastYObjectValue =  (int)[[accumulator lastObject] CGPointValue].y;

if (abs(lastYObjectValue - firstYObjectValue) < 4 && abs(lastXObjectValue - firstXObjectValue) > 4) {
    NSLog(@"Horizontal Pan");

    //do something here
}
else if (abs(lastYObjectValue - firstYObjectValue) > 4 && abs(lastXObjectValue - firstXObjectValue) < 4){
    NSLog(@"Vertical Pan");

    //do something here
}

if (accumulator.count > 3)
    [accumulator removeAllObjects];

Eu dei um exemplo aqui:

adicionar pan personalizada no scrollview

let pangesture = UIPanGestureRecognizer(target: self, action: "dragview:")
yourview.addGestureRecognizer(pangesture)


func dragview(panGestureRecognizer:UIPanGestureRecognizer)
{
    let touchlocation = panGestureRecognizer.locationInView(parentview)
    yourview.center.y = touchlocation.y //x for horizontal 
}

Você pode usar simples panGestureRecognizer. Não há necessidade de usar pandirectionregognizerou outras coisas. Basta usar o valor y do translationInview código Abaixo, mover a visualização de arrastar apenas para cima e para baixo

- (void)gesturePan_Handle:(UIPanGestureRecognizer *)gesture {
    if (gesture.state == UIGestureRecognizerStateChanged) {
        CGPoint translation = [gesture translationInView:gesture.view];
        recognizer.view.center = CGPointMake(recognizer.view.center.x, recognizer.view.center.y + translation.y);
        [gesture setTranslation:CGPointMake(0, 0) inView:gesture.view];
    }
}

- (void)dragAction:(UIPanGestureRecognizer *)gesture{
      UILabel *label = (UILabel *)gesture.view;
      CGPoint translation = [gesture translationInView:label];
     label.center = CGPointMake(label.center.x + translation.x,
                             label.center.y + 0);
    [gesture setTranslation:CGPointZero inView:label];}

Criei o método de ação PanGestureRecognizer @selector para o objeto que precisava apenas de rolagem horizontal.

 UIPanGestureRecognizer *gesture = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(smileyDragged:)];
    [buttonObject addGestureRecognizer:gesture];

Maneira rápida

override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
    if let panGestureRecognizer = gestureRecognizer as? UIPanGestureRecognizer {
        return isVerticalGesture(panGestureRecognizer)
    }
    return false
}

private func isVerticalGesture(_ recognizer: UIPanGestureRecognizer) -> Bool {
    let translation = recognizer.translation(in: superview!)
    if fabs(translation.y) > fabs(translation.x) {
        return true
    }
    return false
}

Para todos os usuários Swift por aí, isso fará o trabalho :)

import Foundation
import UIKit.UIGestureRecognizerSubclass


class DirectionPanGestureRecognizer: UIPanGestureRecognizer {

let kDirectionPanThreshold = CGFloat(5)
var drag = true
var moveX = CGFloat(0)
var moveY = CGFloat(0)

override init(target: AnyObject, action: Selector) {
    super.init(target: target, action: action)
}

override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
    super.touchesMoved(touches, withEvent: event)
    if state == .Failed {
        return
    }

    let nowPoint = touches.anyObject()?.locationInView(view)
    let prevPoint = touches.anyObject()?.previousLocationInView(view)
    moveX += prevPoint!.x - nowPoint!.x
    moveY += prevPoint!.y - nowPoint!.y
    if !drag {
        if abs(moveX) > kDirectionPanThreshold {
            state = .Failed
        } else {
            drag = true
        }

    }

}

 override func reset() {
    super.reset()
    moveX = 0
    moveY = 0
    drag = false
}




}

Tomei uma excelente resposta de Lee Goodrich e enviei para Swift 3

import UIKit
import UIKit.UIGestureRecognizerSubclass

enum PanDirection {
    case vertical
    case horizontal
}

class PanDirectionGestureRecognizer: UIPanGestureRecognizer {

    let direction : PanDirection

    init(direction: PanDirection, target: AnyObject, action: Selector) {
        self.direction = direction
        super.init(target: target, action: action)
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {

        super.touchesMoved(touches, with: event)

        if state == .began {

            let vel = velocity(in: self.view!)

            switch direction {

            case .horizontal where fabs(vel.y) > fabs(vel.x):
                state = .cancelled

            case .vertical where fabs(vel.x) > fabs(vel.y):
                state = .cancelled

            default:
                break

            }

        }
    }
}

Gostaria muito de compartilhar minha abordagem, porque todas as outras abordagens são baseadas em uma UIGestureRecognizerDelegateou em uma subclasse UIPanGestureRecognizer.

Minha abordagem é baseada em tempo de execução e swizzling. Não tenho 100% de certeza sobre essa abordagem, mas você pode testá-la e melhorá-la.

Defina a direção de qualquer um UIPanGestureRecognizercom apenas uma linha de código:

UITableView().panGestureRecognizer.direction = UIPanGestureRecognizer.Direction.vertical

use pod 'UIPanGestureRecognizerDirection'ou o código:

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)
    }
}

Eu tentei isso: o que funcionou para mim de acordo com a pergunta descreve

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    if gestureRecognizer is UIPanGestureRecognizer {
        return true
    } else {
        return false
    }
}

SWIFT 4.2

Fui mais longe e fiz uma direção Pan Gesture:

enum PanDirection {
    case up
    case left
    case right
    case down
}

class PanDirectionGestureRecognizer: UIPanGestureRecognizer {
    
    fileprivate let direction: PanDirection
    
    init(direction: PanDirection, target: AnyObject, action: Selector) {
        self.direction = direction
        super.init(target: target, action: action)
    }
    
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesMoved(touches, with: event)
        
        guard state != .failed else { return }

        let vel = velocity(in: view)

        let velocities: [PanDirection: CGFloat]
            = [.up: -vel.y,
               .left: -vel.x,
               .right: vel.x,
               .down: vel.y]

        let sortedKeys = velocities.sorted { $0.1 < $1.1 }

        if let key = sortedKeys.last?.key,
            key != direction {
            state = .cancelled
        }
    }
}

(Usado: https://github.com/fastred/SloppySwiper e https://stackoverflow.com/a/30607392/5790492 )

Aqui está um gesto de deslocamento personalizado no Swift 5

U pode restringir sua direção e o ângulo máximo na direção, você também pode restringir sua velocidade mínima na direção.

enum PanDirection {
    case vertical
    case horizontal
}

struct Constaint {
    let maxAngle: Double
    let minSpeed: CGFloat

    static let `default` = Constaint(maxAngle: 50, minSpeed: 50)
}


class PanDirectionGestureRecognizer: UIPanGestureRecognizer {

    let direction: PanDirection

    let constraint: Constaint


    init(direction orientation: PanDirection, target: AnyObject, action: Selector, constraint limits: Constaint = Constaint.default) {
        direction = orientation
        constraint = limits
        super.init(target: target, action: action)
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        super.touchesMoved(touches, with: event)
        let tangent = tan(constraint.maxAngle * Double.pi / 180)
        if state == .began {
            let vel = velocity(in: view)
            switch direction {
            case .horizontal where abs(vel.y)/abs(vel.x) > CGFloat(tangent) || abs(vel.x) < constraint.minSpeed:
                state = .cancelled
            case .vertical where abs(vel.x)/abs(vel.y) > CGFloat(tangent) || abs(vel.y) < constraint.minSpeed:
                state = .cancelled
            default:
                break
            }
        }
    }
}

chame assim:

    let pan = PanDirectionGestureRecognizer(direction: .vertical, target: self, action: #selector(self.push(_:)))
    view.addGestureRecognizer(pan)

    @objc func push(_ gesture: UIPanGestureRecognizer){
        if gesture.state == .began{
            // command for once
        }
    }

ou

    let pan = PanDirectionGestureRecognizer(direction: .horizontal, target: self, action: #selector(self.push(_:)), constraint: Constaint(maxAngle: 5, minSpeed: 80))
    view.addGestureRecognizer(pan)

PanGestureRecognizer A interface contém as seguintes definições:

unsigned int    _canPanHorizontally:1;
unsigned int    _canPanVertically:1;

Não verifiquei isso, mas talvez seja acessível via subclasse.