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,我有问题.手势正在工作,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

以下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

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.

最简单的方法是使用两个独立的手势识别器.您还可以在手势开始时以及使用该locationInView:方法结束时检查触摸的位置.

Answer 3

扩展omz的解决方案:

self.myView是我想要设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存为propertys并将其添加到文件中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];

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");
}