设置 UISwipeGestureRecognizer 的方向

Question

我想将简单的滑动手势识别添加到我基于视图的 iPhone 项目中。应识别所有方向（右、下、左、上）的手势。

UISwipeGestureRecognizer 的文档中指出：

您可以通过使用按位或操作数指定多个 UISwipeGestureRecognizerDirection 常量来指定多个方向。默认方向是 UISwipeGestureRecognizerDirectionRight。

但对我来说这不起作用。当所有四个方向都进行“或”运算时，仅识别向左和向右滑动。

- (void)viewDidLoad {
    UISwipeGestureRecognizer *recognizer;

    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionDown | UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionUp)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release]; 
    [super viewDidLoad];
}

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
    NSLog(@"Swipe received.");
}

我通过在视图中添加四个识别器来修复此问题，但我很好奇为什么它没有像文档中宣传的那样工作？

- (void)viewDidLoad {
    UISwipeGestureRecognizer *recognizer;

    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release];

    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionUp)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release];

    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release];

    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release];

    [super viewDidLoad];
}

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
    NSLog(@"Swipe received.");
}

Answer 1

好像有一个错误。您可以像以前一样指定允许的方向。但是，当您尝试访问在操作选择器方法中触发滑动的实际方向时，您仍然会获得最初设置的位掩码（对于允许的方向）。

这意味着当允许超过 1 个方向时，对实际方向的检查将始终失败。
当您在选择器方法中输出“direction”的值时，您可以很容易地看到它（即-(void)scrollViewSwiped:(UISwipeGestureRecognizer *)recognizer）。

向 Apple 提交了错误报告 (#8276386)。

[更新] 我得到苹果的答复，说该行为按预期工作。

因此，例如在表格视图中，您可以在表格视图单元格中向左或向右滑动以触发“删除”（这会将滑动手势的方向设置为向左和向右）

这意味着原始的解决方法是它应该的方式被使用。方向属性只能用于正确识别手势，但不能在成功识别后执行的方法中用于比较触发识别的实际方向。

Answer 2

我注意到左/右和上/下手势是成对工作的，所以你只需要指定两个手势识别器。而且文档似乎确实是错误的。

Answer 3

好吧，这很糟糕，我通过添加像 Lars 提到的 2 个手势解决了这个问题，并且效果很好......

1）左/右
2) 上/下

  

UISwipeGestureRecognizer *swipeLeftRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    [swipeLeftRight setDirection:(UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionLeft )];
    [self.view addGestureRecognizer:swipeLeftRight];

    UISwipeGestureRecognizer *swipeUpDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    [swipeUpDown setDirection:(UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown )];
    [self.view addGestureRecognizer:swipeUpDown];

Answer 4

UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipe:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
[self.view addGestureRecognizer:recognizer];
[recognizer release];

recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipe:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
[self.view addGestureRecognizer:recognizer];
[recognizer release];

现在这是 didSwipe 函数

- (void) didSwipe:(UISwipeGestureRecognizer *)recognizer{
      if([recognizer direction] == UISwipeGestureRecognizerDirectionLeft){
          //Swipe from right to left
          //Do your functions here
      }else{
          //Swipe from left to right
          //Do your functions here
      }
 }

Answer 5

如果您使用 Xcode 4.2，您可以在情节提要中添加手势识别器，然后将 GUI 手势识别器链接到 IBActions。

您可以在实用程序窗格（右窗格底部）的对象库中找到手势识别器。

然后只需按住 Control 键拖动到适当的操作即可。

Answer 6

如果您希望它检测所有四个方向，则需要创建四个实例，就像您在解决方法中所做的那样。

原因如下：
您创建的 UISwipeGestureRecognizer 的同一实例是作为发送者传递给选择器的实例。因此，如果您将其设置为识别所有四个方向，则 sgr.direction == xxx 它将返回 true，其中 xxx 是四个方向之一。

这是一个涉及较少代码的替代解决方法（假设使用 ARC）：

for(int d = UISwipeGestureRecognizerDirectionRight; d <= UISwipeGestureRecognizerDirectionDown; d = d*2) {
    UISwipeGestureRecognizer *sgr = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    sgr.direction = d;
    [self.view addGestureRecognizer:sgr];
}

Answer 7

Swift 2.1

我必须使用以下内容

    for var x in [
        UISwipeGestureRecognizerDirection.Left,
        UISwipeGestureRecognizerDirection.Right,
        UISwipeGestureRecognizerDirection.Up,
        UISwipeGestureRecognizerDirection.Down
    ] {
        let r = UISwipeGestureRecognizer(target: self, action: "swipe:")
        r.direction = x
        self.view.addGestureRecognizer(r)
    }

Answer 8

以下是 UISwipeGestureRecognizer 使用的代码示例。注意评论。

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //add gesture recognizer. The 'direction' property of UISwipeGestureRecognizer only sets the allowable directions. It does not return to the user the direction that was actaully swiped. Must set up separate gesture recognizers to handle the specific directions for which I want an outcome.
    UISwipeGestureRecognizer *gestureRight;
    UISwipeGestureRecognizer *gestureLeft;
    gestureRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeRight:)];//direction is set by default.
    gestureLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeLeft:)];//need to set direction.
    [gestureLeft setDirection:(UISwipeGestureRecognizerDirectionLeft)];
    //[gesture setNumberOfTouchesRequired:1];//default is 1
    [[self view] addGestureRecognizer:gestureRight];//this gets things rolling.
    [[self view] addGestureRecognizer:gestureLeft];//this gets things rolling.
}

swipeRight 和 swipeLeft 是用于根据向左或向右滑动执行特定活动的方法。例如：

- (void)swipeRight:(UISwipeGestureRecognizer *)gesture
{
    NSLog(@"Right Swipe received.");//Lets you know this method was called by gesture recognizer.
    NSLog(@"Direction is: %i", gesture.direction);//Lets you know the numeric value of the gesture direction for confirmation (1=right).
    //only interested in gesture if gesture state == changed or ended (From Paul Hegarty @ standford U
    if ((gesture.state == UIGestureRecognizerStateChanged) ||
    (gesture.state == UIGestureRecognizerStateEnded)) {

    //do something for a right swipe gesture.
    }
}

Answer 9

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");
        //Left
        //Right
        //Top
        //Bottom
    }

Answer 10

嗯，奇怪，它对我来说很完美，我做了完全相同的事情，

我认为你应该尝试查看

UIGestureRecognizerDelegate 方法

- (BOOL)gestureRecognizerShouldBegin:(UISwipeGestureRecognizer *)gestureRecognizer {
   // also try to look what's wrong with gesture
   NSLog(@"should began gesture %@", gestureRecognizer);
   return YES;
}

日志中的

，你必须看到类似的内容：应该开始手势 ;目标= <(action=actionForUpDownSwipeGestureRecognizer:, 目标=)>;方向=上、下、左、右>

Answer 11

用这个，应该是位运算

   gesture.direction & UISwipeGestureRecognizerDirectionUp || 
   gesture.direction & UISwipeGestureRecognizerDirectionDown

Answer 12

这让我发疯。我终于找到了一种拥有多个 swipeGestureRecognizer 的可靠方法。

如果您的“动作”选择器的名称在多个 swipeGestureRecognizer 中相同，那么 iOS 中似乎存在一个错误。如果您只是以不同的方式命名它们，例如handleLeftSwipeFrom 和handleRightSwipeFrom，则一切正常。

UISwipeGestureRecognizer *recognizer;

recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleLeftSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];

recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleRightSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];