[英]Detect swiping in UICollectionView
I need to perform a specific action when the user swipes the uicollectionview. 我需要在用户滑动uicollectionview时执行特定操作。 I built it in a way that each cell captures the full screen. 我以每个单元格捕获全屏的方式构建它。
I tried those ways: 我试过这些方法:
A. scrollViewDidEndDecelerating 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");
}
}
But the scrollVelocity
returns null. 但scrollVelocity
返回null。 The method is being called. 正在调用该方法。
B. UISwipeGestureRecognizer B. UISwipeGestureRecognizer
In ViewDidLoad
of my UIViewController
which delegates to UICollectionViewDataSource
and UIGestureRecognizerDelegate
I added: 在我的UIViewController
ViewDidLoad
,它委托给UICollectionViewDataSource
和UIGestureRecognizerDelegate
我添加了:
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];
and the followings in the UiViewController: 以及UiViewController中的以下内容:
#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;
}
But none are called. 但没有一个被称为。
What is wrong? 怎么了? I am developing for ios7 我正在为ios7开发
You are not setting the delegate of the gestures: 您没有设置手势的代理:
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];
i was trying to do same thing with you (by full size cell frames in a UICollectionView). 我试图与你做同样的事情(通过UICollectionView中的全尺寸单元格框架)。 Just delegating with self is not sufficient enought, because UICollectionView may has it's own gesture recognizer. 仅使用self委托是不够的,因为UICollectionView可能拥有它自己的手势识别器。 So below trick was worked in may case. 所以下面的伎俩在5个案例中有效。
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.backgroundColor = .red
let leftGR = UISwipeGestureRecognizer(target: self, action: #selector(self.swipeHandler_Left(gestureRecognizer:)))
leftGR.numberOfTouchesRequired = 1
leftGR.direction = .left
leftGR.delegate = self
self.view.addGestureRecognizer(leftGR)
}
@objc func swipeHandler_Left(gestureRecognizer : UISwipeGestureRecognizer!) {
if gestureRecognizer.state == .ended {
// Perform action.
print("***Free to Delete Old Cell")
}
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
sorry for my swifty answer, pls try to translate objc :) 对不起我的回答,请尝试翻译objc :)
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