Wykryj przesuwanie w UICollectionView

Question

Muszę wykonać określone działanie, gdy użytkownik przeciągnie widok pikowania. Zbudowałem go w taki sposób, że każda komórka przechwytuje cały ekran.

Próbowałem te sposoby:

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"); 
    } 
} 

Ale scrollVelocity zwraca NULL. Metoda jest wywoływana.

B. UISwipeGestureRecognizer

W ViewDidLoad moich UIViewController które delegatów UICollectionViewDataSource i UIGestureRecognizerDelegate I dodaje:

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]; 

i co nastepuje w 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; 
} 

ale żaden są nazywane.

Co jest nie tak? Zajmuję dla ios7

Answer 1

Nie jesteś ustawienie delegat gestów:

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];