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Collection view flowlayout cells are overlapping how to#Update: There is now a Part 2 which covers how to make an API call to IMDB and populate the cells with movie images. Previously, we covered Table Views in this intro tutorial. If you’re new to Collection Views, they’re very similar to Table Views in that they have a Data Source, Delegate, and reusable cells. This tutorial covers how to leverage a Table View to handle vertical scrolling, while using a Collection View for the horizontal part. This is where Table Views come into the picture. Collection Views do support scrolling in both directions, but its sections are not designed to scroll independently. Since the images are in sort of a grid, a Collection View seems like a natural tool of choice. Want to give users a way to casually explore different categories of content without having to tap into a detail page? Independently scrolling rows can help you achieve this effect. Netflix and the App Store use this type of UI for their discovery dashboards. Collection view flowlayout cells are overlapping download#You can download the finished project from github.Nest UICollectionView inside UITableView for independent scrolling Next, we can calculate the major cell index (the cell that we need to snap to) Add the following function to the viewController: private func indexOfMajorCell() -> Int, completion: nil) This will just stop any sliding effect after the user lift the finger. Collection view flowlayout cells are overlapping code#And here we Have our first line of code inside the function scrollViewWillEndDragging: // Stop scrollView sliding: targetContentOffset.pointee = ntentOffset So first, if the user left us velocity, there will be still sliding going and that will interfere with our snapping plan. When the user finished a drag, we would like to snap to the page that appears the most - “the major cell”: The second parameter of this function is a pointer to the contentOffset the scrollView will have once the sliding will come to an end (parameter targetContentOffset). The velocity may be different then zero if the user lift the finger with a swing movement. This function will gives us the velocity of the scrollView in the moment the user lift the finger and stopped the dragging gesture. Remember: collectionView is a UIScrollView and UICollectionViewDelegate inherits from UIScrollViewDelegate. Now all is left is for our viewController to conform to UICollectionViewDelegate and to implement the following function: func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer) We will achieve zero spacing between cells by adding the following line to the function viewDidLoad(): collectionViewLayout.minimumLineSpacing = 0 ![]() We can create the illusion of spacing between cells by encapsulating the inner elements of the cells (like labels, images or in our case: buttons) in the center of cell (see Main.storyboard). It will make calculation much easier for us. Next, the spacing between two cells should be zero. This function does some magic calculations - don’t worry about it, these calculations are very specific for this example. Open the starter project and go to the file ViewController, there I’m setting the cell size and the insets of the collectionView inside the function configureCollectionViewLayoutItemSize() - the inset can be of any size for paging to work, but I wanted the next cell and previous cell to peek from the sides, so calculation for the inset is made in the function calculateSectionInset(). You can download the starter project from Github and you will find a link to the finished project at the bottom of the tutorial. The collection view in the bottom of the screen is missing one thing - paging! So just marking “enable paging” in the interface builder won’t work - we will have to implement paging ourselves!įor this tutorial I already created a starter app that does all the above. ![]()
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