如何识别所有四个方向的滑动？

Question

我需要识别所有方向的滑动手势（上下左右），虽然不是同时进行，但我需要能够识别它们。

我尝试过:

  UISwipeGestureRecognizer *Swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(SwipeRecognizer:)];
  Swipe.direction = (UISwipeGestureRecognizerDirectionLeft | 
                     UISwipeGestureRecognizerDirectionRight |
                     UISwipeGestureRecognizerDirectionDown | 
                     UISwipeGestureRecognizerDirectionUp);
  [self.view addGestureRecognizer:Swipe];
  [Swipe release];

但是在SwipeRecognizer上没有任何显示。

这是SwipeRecognizer的代码：

- (void) SwipeRecognizer:(UISwipeGestureRecognizer *)sender {
  if ( sender.direction == UISwipeGestureRecognizerDirectionLeft )
    NSLog(@" *** SWIPE LEFT ***");
  if ( sender.direction == UISwipeGestureRecognizerDirectionRight )
    NSLog(@" *** SWIPE RIGHT ***");
  if ( sender.direction == UISwipeGestureRecognizerDirectionDown )
    NSLog(@" *** SWIPE DOWN ***");
  if ( sender.direction == UISwipeGestureRecognizerDirectionUp )
    NSLog(@" *** SWIPE UP ***");
}

我该如何做到这一点？如何将所有不同的方向分配给我的 Swipe 对象？

- elp

Answer 1

你可以像这样设置方向

  UISwipeGestureRecognizer *Swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(SwipeRecognizer:)];
  Swipe.direction = (UISwipeGestureRecognizerDirectionLeft | 
                     UISwipeGestureRecognizerDirectionRight |
                     UISwipeGestureRecognizerDirectionDown | 
                     UISwipeGestureRecognizerDirectionUp);

当您收到回调时，这就是方向，因此所有测试都失败是正常的。如果您有

- (void) SwipeRecognizer:(UISwipeGestureRecognizer *)sender {
  if ( sender.direction | UISwipeGestureRecognizerDirectionLeft )
    NSLog(@" *** SWIPE LEFT ***");
  if ( sender.direction | UISwipeGestureRecognizerDirectionRight )
    NSLog(@" *** SWIPE RIGHT ***");
  if ( sender.direction | UISwipeGestureRecognizerDirectionDown )
    NSLog(@" *** SWIPE DOWN ***");
  if ( sender.direction | UISwipeGestureRecognizerDirectionUp )
    NSLog(@" *** SWIPE UP ***");
}

测试将会成功（但是它们都会成功，因此你将无法从中获取任何信息）。如果您想区分不同方向的轻扫，则需要单独使用手势识别器。

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编辑

如评论中所述，请参阅此答案。显然，即使这样也行不通。建议您只创建有一个方向的轻扫手势以使事情变得更容易。

- jbat100

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是的。您创建的手势识别器将告诉您发生了一个滑动手势，但不会告诉您是哪个方向。 - jbat100

最后一句话：“如果你想区分不同方向的滑动，你需要单独使用手势识别器。” 真的为我节省了时间。 - antonio081014

我尝试过这个，但只有在你结合左右或上下时才有效。当你结合这四个方向时，只有左右滑动可以被检测到。 - Danyun Liu

@Danyun 我认为你不应该做任何假设（因为它可能会在操作系统版本之间发生变化，因为它没有记录），我建议你在每个方向上使用一个识别器。 - jbat100

我为其有用性投了赞成票，但看到变量/方法名称使用大驼峰式命名法让我感到难过 :( - Joel Balmer

Answer 2

很遗憾，您不能使用direction属性来监听识别器，它只会给出识别器所检测到的方向。我已经使用了两个不同的UISwipeGestureRecognizer来实现此目的，可以在这里查看我的答案：https://dev59.com/DGoy5IYBdhLWcg3wCpsz#16810160

- Yunus Nedim Mehel

Answer 3

我之前遇到过这个问题。最后我创建了一个UIView子类，重写了touchesMoved:方法，并进行了一些计算以计算方向。

以下是大致的思路：

#import "OmnidirectionalControl.h"

typedef NS_ENUM(NSInteger, direction) {
    Down = 0, DownRight = 1,
    Right = 2, UpRight = 3,
    Up = 4, UpLeft = 5,
    Left = 6, DownLeft = 7
};

@interface OmnidirectionalControl ()

@property (nonatomic) CGPoint startTouch;
@property (nonatomic) CGPoint endTouch;

@end

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    self.startTouch = [[touches allObjects][0] locationInView:self];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    self.lastTouch = [[[touches allObjects] lastObject] locationInView:self];
    NSLog(@"Direction: %d", [self calculateDirectionFromTouches]);
}

-(direction)calculateDirectionFromTouches {
    NSInteger xDisplacement = self.lastTouch.x-self.startTouch.x;
    NSInteger yDisplacement = self.lastTouch.y-self.startTouch.y;

    float angle = atan2(xDisplacement, yDisplacement);
    int octant = (int)(round(8 * angle / (2 * M_PI) + 8)) % 8;

    return (direction) octant;
}

为了简单起见，在touchesMoved:中，我只记录方向，但是你可以使用该信息做任何你想做的事情（例如将其传递给代理、发布带有它的通知等）。在touchesMoved中，你还需要一些方法来识别滑动是否完成，但这与问题不太相关，所以我会留给你。在calculateDirectionFromTouches中的数学公式在这里有解释。

- pasawaya

Answer 4

我终于找到了最简单的答案，如果你同意，请将其标记为答案。

如果您只有一个方向的滑动手势和平移手势，您只需使用以下代码：

[myPanRecogznier requireGestureRecognizerToFail:mySwipeRecognizer];

但是，如果您有两个或更多的滑动手势，则无法将数组传递给该方法。为此，需要实现UIGestureRecognizerDelegate。

例如，如果您想要识别2个滑动手势（左和右），并且还希望允许用户向上平移，则需要将手势识别器定义为属性或实例变量，并将VC设置为平移手势识别器的代理：

_swipeLeft = [[UISwipeGestureRecognizer alloc] ...]; // use proper init here
_swipeRight = [[UISwipeGestureRecognizer alloc] ...]; // user proper init here
_swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
_swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
_pan = [[UIPanGestureRecognizer alloc] ...]; // use proper init here

_pan.delegate = self;

// then add recognizers to your view

您需要实现 - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer 委托方法，示例如下：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    if (gestureRecognizer == _pan && (otherGestureRecognizer == _swipeLeft || otherGestureRecognizer == _swipeRight)) {
        return YES;
    }

    return NO;
}

这告诉平移手势识别器仅在左右滑动都无法被识别时才起作用 - 完美！

希望在未来，苹果可以让我们向 requireGestureRecognizerToFail: 方法传递一个数组。

- Alex the Ukrainian

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目前被接受的答案无法正常工作。这个应该是被接受的答案。 - Rupert Pupkin

Answer 5

使用UIPanGestureRecogizer并检测您关心的滑动方向。有关详细信息，请参阅UIPanGestureRecognizer文档。-rrh

// add pan recognizer to the view when initialized
UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panRecognized:)];
[panRecognizer setDelegate:self];
[self addGestureRecognizer:panRecognizer]; // add to the view you want to detect swipe on


-(void)panRecognized:(UIPanGestureRecognizer *)sender
{
    if (sender.state == UIGestureRecognizerStateBegan) {
        // you might want to do something at the start of the pan
    }

    CGPoint distance = [sender translationInView:self]; // get distance of pan/swipe in the view in which the gesture recognizer was added
    CGPoint velocity = [sender velocityInView:self]; // get velocity of pan/swipe in the view in which the gesture recognizer was added
    float usersSwipeSpeed = abs(velocity.x); // use this if you need to move an object at a speed that matches the users swipe speed
    NSLog(@"swipe speed:%f", usersSwipeSpeed);
    if (sender.state == UIGestureRecognizerStateEnded) {
        [sender cancelsTouchesInView]; // you may or may not need this - check documentation if unsure
        if (distance.x > 0) { // right
            NSLog(@"user swiped right");
        } else if (distance.x < 0) { //left
            NSLog(@"user swiped left");
        }
        if (distance.y > 0) { // down
            NSLog(@"user swiped down");
        } else if (distance.y < 0) { //up
            NSLog(@"user swiped up");
        }
        // Note: if you don't want both axis directions to be triggered (i.e. up and right) you can add a tolerence instead of checking the distance against 0 you could check for greater and less than 50 or 100, etc.
    }
}

使用以下代码更改状态结束代码

//如果您只想从上、下、左、右单向切换

if (sender.state == UIGestureRecognizerStateEnded) {
        [sender cancelsTouchesInView]; // you may or may not need this - check documentation if unsure
        if (distance.x > 0 && abs(distance.x)>abs(distance.y)) { // right
            NSLog(@"user swiped right");
        } else if (distance.x < 0 && abs(distance.x)>abs(distance.y)) { //left
            NSLog(@"user swiped left");
        }
        if (distance.y > 0 && abs(distance.y)>abs(distance.x)) { // down
            NSLog(@"user swiped down");
        } else if (distance.y < 0 && abs(distance.y)>abs(distance.x)) { //up
            NSLog(@"user swiped up");
        }

    } 

- Richie Hyatt

Answer 6

您可以通过SwipeGesture仅添加一个对角线，然后...

    UISwipeGestureRecognizer *swipeV = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(action)];
    UISwipeGestureRecognizer *swipeH = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(action)];
    swipeH.direction = ( UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight  );
    swipeV.direction = ( UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown );
    [self addGestureRecognizer:swipeH];
    [self addGestureRecognizer:swipeV];
     self.userInteractionEnabled = YES;

- Damien Romito

Answer 7

这可能不是最好的解决方案，但您始终可以为要检测的每个滑动方向指定不同的UISwipeGestureRecognizer。

在viewDidLoad方法中，只需定义所需的UISwipeGestureRecognizer：

- (void)viewDidLoad{
    UISwipeGestureRecognizer *recognizerUp = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeUp:)];
    recognizerUp.direction = UISwipeGestureRecognizerDirectionUp;
    [[self view] addGestureRecognizer:recognizerUp];

    UISwipeGestureRecognizer *recognizerDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeDown:)];
    recognizerDown.direction =  UISwipeGestureRecognizerDirectionDown;
    [[self view] addGestureRecognizer:recognizerDown];
}

然后只需实现相应的方法来处理滑动操作：

- (void)handleSwipeUp:(UISwipeGestureRecognizer *)sender{
    if (sender.state == UIGestureRecognizerStateEnded){
        NSLog(@"SWIPE UP");
    }
}


- (void)handleSwipeDown:(UISwipeGestureRecognizer *)sender{
    if (sender.state == UIGestureRecognizerStateEnded){
        NSLog(@"SWIPE DOWN");
    }
}

- Daniel Belém Duarte

Answer 8

UISwipeGestureRecognizer *Updown=[[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleGestureNext:)];
        Updown.delegate=self;
        [Updown setDirection:UISwipeGestureRecognizerDirectionDown | UISwipeGestureRecognizerDirectionUp];
        [overLayView addGestureRecognizer:Updown];

        UISwipeGestureRecognizer *LeftRight=[[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleGestureNext:)];
        LeftRight.delegate=self;
        [LeftRight setDirection:UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight];
        [overLayView addGestureRecognizer:LeftRight];
        overLayView.userInteractionEnabled=NO;


-(void)handleGestureNext:(UISwipeGestureRecognizer *)recognizer
{
    NSLog(@"Swipe Recevied");
}

- bhavik