Rileva il passaggio del mouse in UICollectionView

Question

È necessario eseguire un'azione specifica quando l'utente scorre la vista di raccolta. L'ho costruito in modo che ogni cella catturi l'intero schermo.

ho provato questi modi:

A. scrollViewDidEndDecelerating

# pragma UIScrollView 
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{ 
    NSLog(@"detecting scroll"); 
    for (UICollectionViewCell *cell in [_servingTimesCollectionView visibleCells]) { 
     NSIndexPath *indexPath = [_servingTimesCollectionView indexPathForCell:cell]; 
     CGPoint scrollVelocity = [scrollView.panGestureRecognizer velocityInView:_servingTimesCollectionView]; 
     if (scrollVelocity.x > 0.0f) 
      NSLog(@"going right"); 
     else if (scrollVelocity.x < 0.0f) 
      NSLog(@"going left"); 
    } 
} 

Ma i scrollVelocity restituisce null. Il metodo viene chiamato.

B. UISwipeGestureRecognizer

In ViewDidLoad dei miei UIViewController che delega al UICollectionViewDataSource e UIGestureRecognizerDelegate ho aggiunto:

UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeRight:)]; 
swipeRight.numberOfTouchesRequired = 1; 
[swipeRight setDirection:UISwipeGestureRecognizerDirectionRight]; 

UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeLeft:)]; 
swipeRight.numberOfTouchesRequired = 1; 
[swipeRight setDirection:UISwipeGestureRecognizerDirectionRight]; 

[_servingTimesCollectionView addGestureRecognizer:swipeRight]; 
[_servingTimesCollectionView addGestureRecognizer:swipeLeft]; 

e quanto segue nella UIViewController:

#pragma mark - UISwipeGestureRecognizer Action 
-(void)didSwipeRight: (UISwipeGestureRecognizer*) recognizer { 
    NSLog(@"Swiped Right"); 
} 

-(void)didSwipeLeft: (UISwipeGestureRecognizer*) recognizer { 
    NSLog(@"Swiped Left"); 
} 

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer  shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer 
{ 
    NSLog(@"Asking permission"); 
    return YES; 
} 

Ma nessuno sono chiamati.

Cosa c'è che non va? Sto sviluppando per iOS7

Answer 1

Non sta impostando il delegato dei gesti:

UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeRight:)]; 
    swipeRight.delegate = self; 
    swipeRight.numberOfTouchesRequired = 1; 
    [swipeRight setDirection:UISwipeGestureRecognizerDirectionRight]; 

    UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipeLeft:)]; 
    swipeLeft.delegate = self; 
    swipeLeft.numberOfTouchesRequired = 1; 
    [swipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft];