UICollectionView with paging – setting page width

by

Another way is to create a custom UICollectionViewFlowLayout and override the method like so: 

- (CGPoint)targetContentOffsetForProposedContentOffset:(CGPoint)offset 
                                 withScrollingVelocity:(CGPoint)velocity {

    CGRect cvBounds = self.collectionView.bounds;
    CGFloat halfWidth = cvBounds.size.width * 0.5f;
    CGFloat proposedContentOffsetCenterX = offset.x + halfWidth;

    NSArray* attributesArray = [self layoutAttributesForElementsInRect:cvBounds];

    UICollectionViewLayoutAttributes* candidateAttributes;
    for (UICollectionViewLayoutAttributes* attributes in attributesArray) {

        // == Skip comparison with non-cell items (headers and footers) == //
        if (attributes.representedElementCategory != 
            UICollectionElementCategoryCell) {
            continue;
        }

        // == First time in the loop == //
        if(!candidateAttributes) {
            candidateAttributes = attributes;
            continue;
        }

        if (fabsf(attributes.center.x - proposedContentOffsetCenterX) < 
            fabsf(candidateAttributes.center.x - proposedContentOffsetCenterX)) {
            candidateAttributes = attributes;
        }
    }

    return CGPointMake(candidateAttributes.center.x - halfWidth, offset.y);

}

If you are looking for a Swift solution, check out this Gist

  • note: this will work when we are really showing preview cells (even if they have an alpha of 0.0f). This is because if the preview cells are not available at the time of scrolling their attributes object will not be passed in the loop…

More Related Contents:

  1. Displaying images on another view controller when button is clicked
  2. UICollectionView Self Sizing Cells with Auto Layout
  3. Fatal error: unexpectedly found nil while unwrapping an Optional values [duplicate]
  4. How to make a simple collection view with Swift
  5. Left Align Cells in UICollectionView
  6. Creating a UICollectionView programmatically
  7. UICollectionView – dynamic cell height? [duplicate]
  8. How to adjust height of UICollectionView to be the height of the content size of the UICollectionView?
  9. UICollectionView inside a UITableViewCell — dynamic height?
  10. UICollectionView, full width cells, allow autolayout dynamic height?
  11. UICollectionView flowLayout not wrapping cells correctly
  12. UICollectionView: Animate cell size change on selection
  13. Dynamic cell width of UICollectionView depending on label width
  14. ios 8 Swift – TableView with embedded CollectionView
  15. UICollectionView Set number of columns
  16. How to determine height of UICollectionView with FlowLayout
  17. Auto Layout in UICollectionViewCell not working
  18. Auto-layout: What creates constraints named UIView-Encapsulated-Layout-Width & Height?
  19. UICollectionView spacing margins
  20. Snap to center of a cell when scrolling UICollectionView horizontally
  21. UICollectionView – Horizontal scroll, horizontal layout?
  22. iOS 10 bug: UICollectionView received layout attributes for a cell with an index path that does not exist
  23. UICollectionView adding UICollectionCell
  24. Why on Xcode 11, UICollectionViewCell changes size as soon as you scroll (I already set size in sizeForItem AtIndexPath:)?
  25. UIButton in cell in collection view not receiving touch up inside event
  26. UICollectionView and SwiftUI?
  27. How to scroll to a particluar index in collection view in swift
  28. uicollectionview remove top padding
  29. UICollectionView auto scroll to cell at IndexPath
  30. Warning: UICollectionViewFlowLayout has cached frame mismatch for index path ‘abc’

Leave a Comment