Guilherme Guilherme - 8 months ago 121
iOS Question

UICollectionView with paging - setting page width

I have a Collection View that can show about 3.5 cells at a time, and I want it to be paging-enabled. But I'd like it to snap to each cell (just like the App Store app does), and not scroll the full width of the view. How can I do that?


You can snap to cells by being the delegate of the collection view and implementing the method:

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset

This tells you that the user has finished a drag and it allows you to modify the targetContentOffset to align with your cells (i.e. round to the nearest cell). Note that you need to be careful about how you modify the targetContentOffset; in particular, you need to avoid changing it so that the view needs to scroll in the opposite direction of the passed velocity, or you'll get animation glitches. You can probably find many examples of this if you google for that method name.