Question

所以我正在制作一个带有pageControl的页面（它是一个包含多个视图的页面，带有指示您所在页面的点），我的代码在viewDidLoad中如下所示：

UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeAction:)];
UIView *temp = [[UIView alloc]initWithFrame:self.view.frame];
temp.backgroundColor = [UIColor clearColor];
[temp addGestureRecognizer:swipe];
[self.view addSubview:temp];

在swipeAction选择器中我有：

- (void)swipeAction: (UISwipeGestureRecognizer *)sender{
    NSLog(@"Swipe action called");
    if (sender.direction == UISwipeGestureRecognizerDirectionLeft) {
        //Do Something
    }
    else if (sender.direction == UISwipeGestureRecognizerDirectionRight){
        //Do Something Else
    }
}

令我惊讶的是，此方法仅在您向右滑动时起作用（即调用else if块）。向左滑动时，swipeAction甚至无法调用！这很奇怪，为什么会发生这种情况，我该如何更改代码？任何回复表示赞赏。非常感谢！

Answer 1

这里有一些你应该注意的事情。首先，您必须为要观察的每个方向创建一个手势。这不是什么大问题，因为你可以简单地给他们相同的选择器，它就像一个两个方向的手势。

UISwipeGestureRecognizer *leftSwipe = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeAction:)];
leftSwipe.direction = UISwipeGestureRecognizerDirectionLeft;

UISwipeGestureRecognizer *rightSwipe = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeAction:)];
rightSwipe.direction = UISwipeGestureRecognizerDirectionRight;


UIView *temp = [[UIView alloc]initWithFrame:self.view.frame];

temp.backgroundColor = [UIColor clearColor];
[temp addGestureRecognizer:leftSwipe];
[temp addGestureRecognizer:rightSwipe];

[self.view addSubview:temp];

其次，您从未指定手势的方向，使其默认为右侧（或方向枚举上的1）

来自documentation：

默认方向是UISwipeGestureRecognizerDirectionRight。有关更多信息，请参阅UISwipeGestureRecognizerDirection常量的说明。

typedef enum {
   UISwipeGestureRecognizerDirectionRight = 1 << 0,
   UISwipeGestureRecognizerDirectionLeft  = 1 << 1,
   UISwipeGestureRecognizerDirectionUp    = 1 << 2,
   UISwipeGestureRecognizerDirectionDown  = 1 << 3
} UISwipeGestureRecognizerDirection;

Answer 2

雨燕4

let swiper = UISwipeGestureRecognizer(target: self, action: #selector(self.swipeFunction(sender:)))
swiper.direction = UISwipeGestureRecognizer.Direction.right
let swipel = UISwipeGestureRecognizer(target: self, action: #selector(self.swipeFunction(sender:)))
swipel.direction = UISwipeGestureRecognizer.Direction.left
UIView().addGestureRecognizer(swiper)
UIView().addGestureRecognizer(swipel)

@objc func swipeFunction(sender: UISwipeGestureRecognizer) {
    print(sender)
}

您应该能够从那里弄清楚，您可以为每个方向的UIView添加一个UISwipeGestureRecognizer

Answer 3

swipe.direction设置您正在识别的方向，它不会告诉您哪个方向被刷过。在创建识别器时添加此行：

swipe.direction = UISwipeGestureRecognizerDirectionLeft|UISwipeGestureRecognizerDirectionRight;

如果您需要检测哪个方向被滑动，只需使用两个不同的识别器，一个用于左侧，一个用于右侧。

UISwipeGestureRecognizer只有一个方向可行

3 个答案: