UICollectionViewCell Size According to Screen/ FrameSize Swift

Question

I have a collection View with an image in each collectionViewCell. I want to have only 3 cells for any given frame/ screen size. How do I implement this. I have written some code based on this post

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

    let numberOfCell = 3
    let cellWidth: CGFloat = [[UIScreen mainScreen].bounds].size.width/numberOfCell
    return CGSizeMake(cellWidth, cellWidth)
    }

But its not working and giving an error. What is the best way to do this.

Answer 1

Here is your swift code:

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

    let numberOfCell: CGFloat = 3   //you need to give a type as CGFloat
    let cellWidth = UIScreen.mainScreen().bounds.size.width / numberOfCell
    return CGSizeMake(cellWidth, cellWidth)
}

Here the type of numberOfCell must be a CGFloat because UIScreen.mainScreen().bounds.size.width return a CGFloat value so if you want to divide it with numberOfCell then type numberOfCell must be CGFloat because you can not divide CGFloat with Int.

Answer 2

Here is Swift 3 code and you to have implement UICollectionViewDelegateFlowLayout

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let numberOfCell: CGFloat = 3   //you need to give a type as CGFloat
    let cellWidth = UIScreen.main.bounds.size.width / numberOfCell
    return CGSize(width: cellWidth, height: cellWidth)
}