UICollectionView align logic missing in horizontal paging scrollview

Question

I\'ve got a UICollectionView, which works ok, until I start scrolling. Here some pics first:

Answer 1

My answer is based on answer https://stackoverflow.com/a/27242179/440168 but is more simple.

You should place UIScrollView above UICollectionView and give them equal sizes:

@property (nonatomic, weak) IBOutlet UICollectionView *collectionView;
@property (nonatomic, weak) IBOutlet UIScrollView *scrollView;

Then configure contentInset of collection view, for example:

CGFloat inset = self.view.bounds.size.width*2/9;
self.collectionView.contentInset = UIEdgeInsetsMake(0, inset, 0, inset);

And contentSize of scroll view:

self.scrollView.contentSize = CGSizeMake(self.placesCollectionView.bounds.size.width*[self.collectionView numberOfItemsInSection:0],0);

Do not forget to set delegate of scroll view:

self.scrollView.delegate = self;

And implement main magic:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    if (scrollView == self.scrollView) {
        CGFloat inset = self.view.bounds.size.width*2/9;
        CGFloat scale = (self.placesCollectionView.bounds.size.width-2*inset)/scrollView.bounds.size.width;
        self.collectionView.contentOffset = CGPointMake(scrollView.contentOffset.x*scale - inset, 0);
    }
}