set fixed number of cells per row in UICollectionViewController

fixed number of cells per row UICollectionViewController

func collectionView(collectionView: UICollectionView,
    layout collectionViewLayout: UICollectionViewLayout,
    sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {

        let flowLayout = collectionViewLayout as! UICollectionViewFlowLayout
        let totalSpace = flowLayout.sectionInset.left
            + flowLayout.sectionInset.right
            + (flowLayout.minimumInteritemSpacing * CGFloat(numberOfItemsPerRow - 1))
        let size = Int((collectionView.bounds.width - totalSpace) / CGFloat(numberOfItemsPerRow))
        return CGSize(width: size, height: size)
}

/*This allows for any spacing between the cells. It assumes an Int member variable called numberOfItemsPerRow and also that all the cells are square and the same size. As noted in jhilgert00's answer we must also react to orientation changes, but now by using viewWillTransitionToSize as willRotateToInterfaceOrientation is depreciated.

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answered Mar 6 at 12:35

sgib
13
*/

http://stackoverflow.com/questions/14674986/uicollectionview-set-number-of-columns

Take note of implementing UICollectionViewDelegateFlowLayout