ios UIPanGestureRecognizer - 仅垂直或水平

UIPanGestureRecognizer - Only vertical or horizontal

提问by LocoMike

I have a view that has a UIPanGestureRecognizerto drag the view vertically. So in the recognizer callback, I only update the y-coordinate to move it. The superview of this view, has a UIPanGestureRecognizerthat will drag the view horizontally, just updating the x-coordinate.

我有一个视图，UIPanGestureRecognizer可以垂直拖动视图。所以在识别器回调中，我只更新 y 坐标来移动它。这个视图的超级视图，有一个UIPanGestureRecognizer会水平拖动视图，只是更新 x 坐标。

The problem is that the first UIPanGestureRecognizeris taking the event to move the view vertically, so I can not use the superview gesture.

问题是第一个UIPanGestureRecognizer是通过事件垂直移动视图，所以我不能使用超级视图手势。

I have tried

我试过了

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

and both will work, but I don't want that. I want the horizontally to be detected only if the movement is clearly horizontal. So it would be great if the UIPanGestureRecognizerhad a direction property.

两者都会起作用，但我不想要那样。我希望只有在运动明显水平时才检测到水平。所以如果UIPanGestureRecognizer有一个方向属性会很棒。

How can I achieve this behavior? I find the docs very confusing, so maybe someone can explain it better here.

我怎样才能实现这种行为？我发现文档非常混乱，所以也许有人可以在这里更好地解释它。

采纳答案by LocoMike

I figured it out creating a subclass of UIPanGestureRecognizer

我想出了创建 UIPanGestureRecognizer 的子类

DirectionPanGestureRecognizer:

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:

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

This will only trigger the gesture if the user starts dragging in the selected behavior. Set the direction property to a correct value and you are all set.

如果用户开始在选定的行为中拖动，这只会触发手势。将 direction 属性设置为正确的值，您就全部设置好了。

回答by Hejazi

Just do this for the vertical pan gesture recognizer, it works for me:

只需为垂直平移手势识别器执行此操作，它对我有用：

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

And for Swift:

而对于斯威夫特：

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

回答by Lee Goodrich

I created a solution with subclassing like in the answer @LocoMike provided, but used the more effective detection mechanism via initial velocity as provided by @Hejazi. I'm also using Swift, but this should be easy to translate to Obj-C if desired.

我创建了一个带有子类化的解决方案，就像@LocoMike 提供的答案一样，但是通过@Hejazi 提供的初始速度使用了更有效的检测机制。我也在使用 Swift，但如果需要，这应该很容易转换为 Obj-C。

Advantages over other solutions:

与其他解决方案相比的优势：

• Simpler and more concise than other subclassing solutions. No additional state to manage.
• Direction detection happens prior to sending Began action, so your pan gesture selector receives no messages if the wrong direction is swiped.
• After initial direction is determined, direction logic is no longer consulted. This results in the generally desired behavior of activating your recognizer if the initial direction is correct, but does not cancel the gesture after it has begun if a user's finger doesn't travel perfectly along the direction.

• 比其他子类化解决方案更简单、更简洁。无需管理额外的状态。
• 方向检测发生在发送开始动作之前，因此如果滑动错误的方向，您的平移手势选择器不会收到任何消息。
• 确定初始方向后，不再参考方向逻辑。如果初始方向正确，这会导致通常需要的行为激活您的识别器，但如果用户的手指没有沿着方向完美移动，则不会在手势开始后取消手势。

Here's the code:

这是代码：

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
            }
        }
    }
}

Example of usage:

用法示例：

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:
    ...
}

回答by Story

I tried to constrain the valid area horizontally with UIPanGestureRecognizer.

我尝试使用 UIPanGestureRecognizer 水平约束有效区域。

- (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;
}

Then, only swiping within thresholdAngledegree horizontally can trigger this pan gesture.

然后，只有在阈值角度范围内水平滑动才能触发此平移手势。

回答by Siavash Alp

Swift 3.0 answer: just handles does the vertical gesture

Swift 3.0 答案：只处理垂直手势

    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

}

回答by Cesar Varela

Swift 3 version of Lee's answer for the lazy

Swift 3 版本 Lee 对懒人的回答

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
            }
        }
    }
}

回答by Borut Tomazin

The following solution solved my problem:

以下解决方案解决了我的问题：

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

This is actually just check if pan is going on main view or tableView.

这实际上只是检查 pan 是在主视图还是 tableView 上进行。

回答by Rob Booth

I took Lee Goodrich's answerand extended it as I needed specifically a single direction pan. Use it like this: let pan = PanDirectionGestureRecognizer(direction: .vertical(.up), target: self, action: #selector(handleCellPan(_:)))

我接受了Lee Goodrich的回答并扩展了它，因为我特别需要一个单向平移。像这样使用它：let pan = PanDirectionGestureRecognizer(direction: .vertical(.up), target: self, action: #selector(handleCellPan(_:)))

I also added some commenting to make it a little clearer what decisions are actually being made.

我还添加了一些评论，以使实际做出的决定更加清晰。

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
                }
            }
        }
    }
}

回答by William Hu

Swift 4.2

斯威夫特 4.2

The solution is just for only support pan gesture vertically, same as horizontal.

该解决方案仅用于垂直支持平移手势，与水平相同。

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

Solution 1:

解决方案1：

@objc func panAction(pan: UIPanGestureRecognizer) {

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

Solution 2:

解决方案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)
    }

Then the swipe gesture will swallow the pan gesture. Of course, you don't need to do anything in swipeAction.

然后滑动手势会吞下平移手势。当然，您不需要在swipeAction.

回答by ArunHyman

You can find the direction dragging on UIViewthrough UIPanGestureRecognizer. Please follow the code.

您可以找到UIView通过拖动的方向UIPanGestureRecognizer。请按照代码。

 - (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;
}