How to display 3 cells per row in UICollectionView?

Question

I used a custom flow layout according to this post. Here is my implementation:

@implementation CustomLayout
-(void)prepareLayout{
[super prepareLayout];
//    [self invalidateLayout];
if(self.collectionView){
    CGSize newItemSize=self.itemSize;

// Number of items per row
    int itemsPerRow=3;

    float totalSpacing=self.minimumLineSpacing*(itemsPerRow-1);

    newItemSize.width=(self.collectionView.bounds.size.width -totalSpacing)/itemsPerRow;

    if(self.itemSize.height>0){
        float itemAspectRatio=self.itemSize.width/self.itemSize.height;
        newItemSize.height=newItemSize.width/itemAspectRatio;
    }

    [self setItemSize:newItemSize];

}


}
@end

This is what I've got: What did I miss? I've come across some other SO posts but no luck so far.

Solution 1

Swift 3.0. Works for both horizontal and vertical scroll directions and variable spacing

Declare number of cells you want per row

let numberOfCellsPerRow: CGFloat = 3

Configure flowLayout to render specified numberOfCellsPerRow

if let flowLayout = collectionView?.collectionViewLayout as? UICollectionViewFlowLayout {
    let horizontalSpacing = flowLayout.scrollDirection == .vertical ? flowLayout.minimumInteritemSpacing : flowLayout.minimumLineSpacing
    let cellWidth = (view.frame.width - max(0, numberOfCellsPerRow - 1)*horizontalSpacing)/numberOfCellsPerRow
    flowLayout.itemSize = CGSize(width: cellWidth, height: cellWidth)
}

Solution 2

//Make use of UICollectionViewDelegateFlowLayout Protocol

class RVC: UICollectionViewController {
//some code
}

extension RVC: UICollectionViewDelegateFlowLayout{

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
    {
          var collectionViewSize = collectionView.frame.size
          collectionViewSize.width = collectionViewSize.width/3.0 //Display Three elements in a row.
          collectionViewSize.height = collectionViewSize.height/4.0
          return collectionViewSize
    }

For more information go through below link.

UICollectionView Set number of columns

Comments

[FlySoFast]

then how about larger screens like iPhone 6 plus or iPad? My app tends to run on many devices.

[IOS developer]

so you have to do like self.view.frame.size.width/3 for any type of device width.

[IOS developer]

you just have to calculate only for two device iPhone and iPad.

[IOS developer]

for iphone 6 and iphone 6 plus you just have to remove launch image source.

[FlySoFast]

well..basically that is what I was doing in the code above: calculate the width and with superview' width and the spaces between the cells.

[IOS developer]

just look at my below screen shot

[xdeleon]

Tested this on a few different devices, but not all. Fails on iPad Air, iPad 5th Gen, both running iOS 11.2. Xcode 9.2, Swift 4. I make this call in viewDidLoad().

[xdeleon]

Tested this on iPhone X and iPhone SE. Both running 11.2, with Xcode 9.2/Swift 4. On both devices it did not work.