ios - 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;
}
}

它不工作:/

Answer 1

这是我的一个项目中的示例:

    // ...

    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");
    }
}