UICollectionView in 2 columns

In order for O UICollectionView to present the cells as expected, you have two options:

1) Increase the size of your cell

In this case, you can simply change the size of the cell in UIStoryboard (easier / faster); or explicitly declare the CGSize that you expect the cell to implement the collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize ( UICollectionViewDelegateFlowLayout ) method

2) Increase the spaces between your cells and the borders

In this case, you can implement the UICollectionViewDelegateFlowLayout protocol methods for this, such as:

• collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets
• collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAtIndex section: Int) -> CGFloat
• collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAtIndex section: Int) -> CGFloat

Hands-on

Suppose you want the cell to have a width of 100px per 100px height with padding of 20px between the edges and the middle. The implementation will be (more or less) like this (not tested):

Swift 2

let cellDimension : CGFloat = 100
let spaceBetweenCells : CGFloat = 20
let numberOfColumns : CGFloat = 2

....

// Layout
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
    return CGSize(width: cellDimension, height: cellDimension)
}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets {
    let width = self.view.frame.width
    let expectUsedSize : CGFloat = (cellDimension * numberOfColumns) + spaceBetweenCells
    let margins = (width - expectUsedSize) / numberOfColumns
    return UIEdgeInsetsMake(spaceBetweenCells, margins, spaceBetweenCells, margins)
}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAtIndex section: Int) -> CGFloat {
    return spaceBetweenCells
}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAtIndex section: Int) -> CGFloat {
    return spaceBetweenCells
}

Swift 3

// Layout
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: cellDimension, height: cellDimension)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    let width = self.view.frame.width
    let expectUsedSize : CGFloat = (cellDimension * numberOfColumns) + spaceBetweenCells
    let margins = (width - expectUsedSize) / numberOfColumns
    return UIEdgeInsetsMake(spaceBetweenCells, margins, spaceBetweenCells, margins)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return spaceBetweenCells
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return spaceBetweenCells
}

Note

In the above code, I used the same space between cells ( spaceBetweenCells ) for UIEdgeInsets of cell (bottom and top). You can (obviously) change this value however you want.

Abs!

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