如何检测滑动手势方向？

Question

我需要检测我的滑动手势的方向，但我遇到了问题。手势有效，但我不知道如何检测方向。 ...

swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(detectSwipe:)];
[swipeGesture setNumberOfTouchesRequired:1];
[swipeGesture setDirection:UISwipeGestureRecognizerDirectionDown | UISwipeGestureRecognizerDirectionUp];
[appView addGestureRecognizer:swipeGesture];

-(void)detectSwipe:(UISwipeGestureRecognizer *)recognizer { 
switch (recognizer.direction) {
    case UISwipeGestureRecognizerDirectionUp:
        NSLog(@"smth1");
        break;


    case UISwipeGestureRecognizerDirectionDown:
        NSLog(@"smth2");
    default:
        break;
}
}

它不起作用：/

Answer 1

这是我的一个项目的示例：

    // ...

    UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipe:)];
    swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
    [self.view addGestureRecognizer:swipeLeft];

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

    UISwipeGestureRecognizer *swipeUp = [[UISwipeGestureRecognizer alloc]  initWithTarget:self action:@selector(didSwipe:)];
    swipeUp.direction = UISwipeGestureRecognizerDirectionUp;
    [self.view addGestureRecognizer:swipeUp];

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

    // ...

- (void)didSwipe:(UISwipeGestureRecognizer*)swipe{

    if (swipe.direction == UISwipeGestureRecognizerDirectionLeft) {
        NSLog(@"Swipe Left");
    } else if (swipe.direction == UISwipeGestureRecognizerDirectionRight) {
        NSLog(@"Swipe Right");
    } else if (swipe.direction == UISwipeGestureRecognizerDirectionUp) {
        NSLog(@"Swipe Up");
    } else if (swipe.direction == UISwipeGestureRecognizerDirectionDown) {
        NSLog(@"Swipe Down");
    }
}

Answer 2

direction 属性仅定义被识别为滑动的允许方向，而不是特定滑动的实际方向。

最简单的方法是使用两个单独的手势识别器。您还可以使用 locationInView: 方法在手势开始和结束时检查触摸的位置。

Answer 3

扩展 omz 的解决方案：

self.myView 是我想要放置手势识别器的视图。下面的代码未经测试，我想最好将识别器保留为属性并将它们添加到 viewDidLoad() 或 xib 中文件。 self 是一个 UIViewController。

UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipedLeft:)];
[swipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft ];
[self.view addGestureRecognizer:swipeLeft];

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

将这两个方法添加到您的 UIViewController 中并添加必要的操作：

- (IBAction)swipedRight:(UISwipeGestureRecognizer *)recognizer
{
    NSLog(@"swiped right");
}

- (IBAction)swipedLeft:(UISwipeGestureRecognizer *)recognizer
{
    NSLog(@"swiped left");
} 

Answer 4

使用 Swift 5 检测滑动手势方向

    override func viewDidLoad() {
    super.viewDidLoad()

         let leftSwipe = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipes(_:)))
         let rightSwipe = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipes(_:)))

         leftSwipe.direction = .left
         rightSwipe.direction = .right

         view.addGestureRecognizer(leftSwipe)
         view.addGestureRecognizer(rightSwipe)
    }

    @objc func handleSwipes(_ sender:UISwipeGestureRecognizer) {

        if (sender.direction == .left) {
                print("Swipe Left")
        }

        if (sender.direction == .right) {
            print("Swipe Right")
        }
    }