UICollectionView How to implement horizontal align scrolling - ios

Question

I have a UICollection which is implemented and works, however I cannot achieve the scrolling I want.
Here is a picture of my UICollectionView, I have resized the grey cell to 250 by 250.
My issue is, when I start scrolling, this is what happens.
My cell first starts off on the far left, but notice what happens if I start to scroll horizontally.
As you can see, the seam between the cells moves over to the left the more I scroll through the cells. This is not what I want.
What I want to achieve is: the cell is aligned to the center, and when you scroll, instead of the center of the cells moving to the left more and more, I want the cell to stay in the middle. Much like a PageViewController does except I want it to be UICollectionViewCells.
I have tried adding in the following code for example:
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
float pageWidth = 210;
float currentOffset = scrollView.contentOffset.x;
float targetOffset = targetContentOffset->x;
float newTargetOffset = 0;
if (targetOffset > currentOffset)
newTargetOffset = ceilf(currentOffset / pageWidth) * pageWidth;
else
newTargetOffset = floorf(currentOffset / pageWidth) * pageWidth;
if (newTargetOffset < 0)
newTargetOffset = 0;
else if (newTargetOffset > scrollView.contentSize.width)
newTargetOffset = scrollView.contentSize.width;
targetContentOffset->x = currentOffset;
[scrollView setContentOffset:CGPointMake(newTargetOffset, 0) animated:YES];
}
Which achieves the even scrolling, however I want to have paging enabled aswell as bounce.
Because if I enable paging and bounce, the scrolling is very smooth and elegant, however If I use the code up above the scrolling is very rugged and mechanical.
So How can I achieve even scrolling that is smooth like apples default scrolling, with my UICollectionViewCell being centred in the middle?
If I didn't explain the problem well enough, this post here explains my problem except I am using one cell instead of three, and I want the scrolling to be smooth and bounce etc.

Answer 1

I think this should work (disable paging):
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
if (!decelerate) {
// do your calculations
[scrollView setContentOffset:CGPointMake(newTargetOffset, 0) animated:YES];
}
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
// do your calculations
[scrollView setContentOffset:CGPointMake(newTargetOffset, 0) animated:YES];
}