ios 如何检测滑动手势方向？

how detect swipe gesture direction?

提问by Tomasz Szulc

i need to detect direction of my swipe gesture and i've got problem with it. gesture is working, but i don't know how to detect direction. ...

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;
}
}

it's not working :/

它不工作：/

采纳答案by omz

The directionproperty only defines the alloweddirections that are recognized as swipes, not the actualdirection of a particular swipe.

该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。

The easiest would be to use two separate gesture recognizers instead. You could also inspect the location of the touch when the gesture starts and when it ends with the locationInView:method.

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

回答by nemelianov

Here is an example from one of my projects:

这是我的一个项目中的一个示例：

    // ...

    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");
    }
}

回答by Yunus Nedim Mehel

Extending omz's solution:

扩展omz的解决方案：

self.myViewis the view I want to put the gesture recognizer on. The code below is not tested, I guess it would be better to keep the recognizers as propertys and add them inside viewDidLoad()or xibfile. selfis a UIViewController.

self.myView是我想要放置手势识别器的视图。下面的代码没有经过测试，我想最好将识别器保留为propertys 并将它们添加到文件viewDidLoad()或xib文件中。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];

Add those two methods to your UIViewControllerand add necessary actions:

将这两个方法添加到您的UIViewController并添加必要的操作：

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

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

回答by Raj Joshi

Swipe Gesture direction detect with Swift 5

使用 Swift 5 进行滑动手势方向检测

    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")
        }
    }