Method scrollToItemAtIndexPath is not working on iOS 14

user_4766759 0
Viewed 956

I am having an issue with scrollToItemAtIndexPath from iOS 14. In the previous iOS versions when the user stopped dragging, the next cell was centered horizontally, now the method scrollToItemAtIndexPath is ignored, and it remains stuck in the first cell.

    - (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
    if( scrollView.tag == 1 ) {
        if (UI_USER_INTERFACE_IDIOM() != UIUserInterfaceIdiomPad){
            *targetContentOffset = scrollView.contentOffset; // set acceleration to 0.0
            float pageWidth = (float) (self.view.frame.size.width)-80;
            int minSpace = 10;
            
            int cellToSwipe = (scrollView.contentOffset.x)/(pageWidth + minSpace) + (velocity.x < 0 ? 0 : 1); // cell width + min spacing for lines
            if (cellToSwipe < 0) {
                cellToSwipe = 0;
            } else if (cellToSwipe >= MIN(6, self.news.count )) {
                cellToSwipe = (int) MIN(6, self.news.count);
            }
            [self.newsCollectionView scrollToItemAtIndexPath: [NSIndexPath indexPathForRow:cellToSwipe inSection:0]
                                            atScrollPosition: UICollectionViewScrollPositionCenteredHorizontally
                                                    animated: YES];

        }
    }
    
}
collectionview ios14 ios
4 Answers

You can use layoutAttributesForItem(at indexPath: IndexPath) of the UICollectionViewLayout to calculate a proper contentOffset

The fix could be like that:

extension UICollectionView {
    func scrollTo(indexPath: IndexPath) {
        let attributes = collectionViewLayout.layoutAttributesForItem(at: indexPath)!
        setContentOffset(attributes.frame.origin, animated: true)
    }
}
user_21696340

scrollToItemAtIndexPath still has some problems on iOS 14, you can use setContentOffsetinstead, and it works for me.

user_143192490

Objective-C version:

UICollectionViewLayoutAttributes *attributes = [collectionView layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:index inSection:section]];
                
[collectionView setContentOffset:attributes.frame.origin animated:YES];

where collectionView is your UICollectionView object, index is the row of the UICollectionView to which you want to scroll to and section is the section of the UICollectionView to which the row belongs to.

user_31507310 
_collectionView.pagingEnabled = NO;
[_collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:(UICollectionViewScrollPositionLeft) animated:NO];
_collectionView.pagingEnabled = YES;
user_77015180
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