uicollectionview

问题 I have a CGPoint and I would like to know which cell from my collection view currently contains that point. Is there any simple way to do this or do I have to write my own method? 回答1: I haven't used UICollectionView s much, but there's a method that seems perfect: - (NSIndexPath *)indexPathForItemAtPoint:(CGPoint)point; The point you pass to the method has to be within the coordinate system of the collection view. You can do: CGPoint convertedPoint = [collectionView convertPoint:point

问题 I have an UICollectionView which loads images of the iPad's memory and displays them in a grid,like Apple's Photos app. The UICollectionViewCell loads thumbnails asynchronously: func setImage(img:String){ dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { //load the image in the background let image = UIImage(contentsOfFile: img) //when done, assign it to the cell's UIImageView dispatch_async(dispatch_get_main_queue(), { if let imageView = self.imageView{

问题 I have a requirement to keep UICollectionViewCell center aligned in portrait mode. Final result should be like : animation I'm using this code to do this: override public func targetContentOffset(forProposedContentOffset proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint { var layoutAttributes: Array = layoutAttributesForElements(in: collectionView!.bounds)! if layoutAttributes.count == 0 { return proposedContentOffset } var firstAttribute:

问题 This is my code for animating the CollectionViewCustomCells. -(void)viewDidAppear:(BOOL)animated{ rowIndex = 0; [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(targetMethod) userInfo:nil repeats:YES]; } -(void)targetMethod { [self.offerCollectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:rowIndex inSection:1] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES]; rowIndex=(rowIndex<parserDataContentArrayForExhibitor.count

问题 I am trying to create a book shelf with an UICollectionView, not unlike the iBooks app. It works nicely, however whenever I insert a new item into the view (by calling insertItemsAtIndexPaths: ), the item is inserted correctly, but my shelf items (which are DecorationViews, subclasses of UICollectionReusableView ) are getting darker and darker, obviously being painted over and over again. However, if a call reloadData on the UICollectionView everything is painted correct. This is what I did

问题 I am trying to use the detail disclosure button on the view controller pictured below (PhotoSearchViewController) to show a UIAlertController that shows the photo description from the ImageUrlItem. When I click the button, it shows that it was pressed, but the alert containing the description does not appear. My code for the ImageUrlItem: import Foundation import Firebase struct ImageUrlItem { //Should I add my description in here? let key: String let imageUrl: String let

问题 I'm using drag and drop to drag images from google onto a collection view. The images are all supposed to have equal widths. After I scroll a bit, some of the cells look like they have equal widths, but some images are too big. The collectionView has a flow layout and horizontal scroll direction. In the following gif, the images start out as if they may have the same width(I can't really tell). When I drag an image in, they resize, and you can immediately see that the two on the left no

问题 Iam using collectionview to load image.These images are loaded from url in background thread. Hence the scrolling is not smooth.The images in url get expired after seconds hence i want to update the image with new image.How can i use the SDWebImage to load image and make scrolling smooth? Can anyone please help me to solve this. 回答1: Use this code [YOUR_CELL_NAME.YOUR_IMAGE_NAME setImageWithURL:[NSURL URLWithString:@"IMAGE URL"] placeholderImage:[UIImage imageNamed:@"PLACEHOLDER IMAGE NAME"]]

问题 I have a local video file playing in a loop using AVPlayerLooper but whenever I press the home button (app enters background) and then reopen the app, the video has stopped playing. I also have an AVPlayerLooper inside of a simple view and not a collectionViewCell. To solve the issue on this view I simply call player.play() inside of applicationDidBecomeActive() . This does not work for the collectionViewCell. Have tried removing playerLayer before the app enters the background and adding it

问题 I am currently trying to build a pinterest style layout while having a dynamic height using autolayout (trying to stay away from manual calcuations of cell heights). I am currently aiming for iOS 9 and greater. I have seen brilliant examples of how to do a dynamic layout and a pinterest layout with calculations specific for each index but not with autolayout. Currently my thoughts are that the item would no its width, i.e. layout has x number of columns and an item could span y columns, so